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ZhiWu Communication Technology
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MX680
User Manual
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ZhiWu Communication Technology MX680 User Manual

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MX680 Hardware Design V2.00
MX680 Hardware Design V2.00
MX680 Hardware Design 1 / 58
MX680 Hardware Design V2.00
MX680 Hardware Design
Version
2.00
Date
2014-05-12
Status
Release
Document Control ID
General Notes
ZhiwuCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by ZhiwuCom. The information provided is based upon requi rement s sp eci fical ly provided to ZhiwuCom by the custo mers. ZhiwuCom has not undertak en a ny indepen dent searc h f or addit ional relevant inform atio n, incl udi ng any information that may be in the customer’s posses si on. F ur th er m or e, s ystem validation of th i s product designed by ZhiwuCom within a larger electronic system remains the responsibility of the customer or the customer’s system integrator. All specifications supplied herein are subject to change.
Copyright
This document contains proprietary technical information which is the property of ZhiwuCom Limited, copying of this document and giving it to others and the using or communication of the contents thereof, are forbidden without express authority. Offenders are liable to the payment of da mages . All rights reserved i n th e ev ent o f grant of a pa tent or the r egi strati on of a utility model or design. All specification supplied herein are subject to change without notice at any time.
Copyright © Shanghai ZhiWu Communication Technology Co.,Ltd. 2012
MX680 Hardware Design 2 / 58
MX680 Hardware Design V2.00
Contents
Version History ...................................................................................................................... 6
1. Introduction ....................................................................................................................... 7
2. MX680 Overview ............................................................................................................... 7
2.1. MX680 Key Features .............................................................................................. 7
2.2. Operating Mode ...................................................................................................... 9
2.3. Functional Diagram ................................................................................................ 11
3. Package Information ........................................................................................................12
3.1. Pin out Diagram .....................................................................................................12
3.2. Pin Description .......................................................................................................13
3.3. Package Dimensions .............................................................................................17
4. Application Interface .........................................................................................................19
4.1. Power Supply .........................................................................................................19
4.1.1. Power supply pin ..........................................................................................21
4.1.2. Monitoring Power Supply .............................................................................21
4.2. Power on/down Scenarios......................................................................................22
4.2.1. Power on MX680 .........................................................................................22
4.2.2. Power down MX680 .....................................................................................23
4.3. Power Saving Mode ...............................................................................................26
4.3.1. Minimum Functionality Mode .......................................................................26
4.3.2. Sleep Mode (AT+QSCLK=1) ........................................................................26
4.3.3. Wake Up MX680 from Sleep Mode (AT+QSCLK=1) ....................................27
4.4. Serial Port and USB Interface ................................................................................27
4.4.1. Function of Serial Port ..................................................................................28
4.4.2. Serial Interfaces ...........................................................................................28
4.4.3. Debug Interface ...........................................................................................30
4.4.4. Software Upgrade and Debug ......................................................................31
4.4.4. UART Application .........................................................................................32
4.5. SIM Card Interface .................................................................................................34
4.5.1. SIM Card Application....................................................................................34
4.5.2.6 Pin SIM Cassette .......................................................................................35
4.6. RI Behaviors ...........................................................................................................36
4.7. Network Status Indication .......................................................................................38
4.8. Operating Status Indication ....................................................................................39
4.8. Antenna Interface ...................................................................................................40
4.8.1. Antenna Interface .........................................................................................40
4.9. A udi o Interfaces .....................................................................................................42
4.9.1 Microphone Int er fac es Co n fig ur ati on ............................................................43
4.9.2 S peaker Interfaces Con fig ur ati o n ..................................................................43
4.9.3 Earphone Interfaces Configuration ...............................................................44
4.9.4 Audio Electronic C har act eri s ti c .....................................................................44
4.9.5 TDD...............................................................................................................45
5. Electrical, Reliability and Radio Characteristics ...............................................................46
5.1 Absolute Maximum Ratings .....................................................................................46
5.2 Operating Temperature ...........................................................................................46
5.3 Digital Interface Characteristics ...............................................................................47
5.4 SIM Card Interface ..................................................................................................47
5.5 SIM_VDD Characteristics........................................................................................48
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MX680 Hardware Design V2.00
5.6 VDD_EXT Characteristics .......................................................................................48
5.7 Current Consumption(VBAT=4.0V) .........................................................................48
5.8 Electro-Static Discha rge ..........................................................................................50
5.9 Radio Characteristics ..............................................................................................51
5.9.1. Module RF Output Power .............................................................................51
5.9.2. Module RF Receive Sensitivity ....................................................................52
5.9.3. Module Operating Frequencies ....................................................................52
6. Manufacturing ..................................................................................................................53
6.1. Top and Bottom View of MX680 .............................................................................53
6.2. Typical Solder Reflow Profile ..................................................................................54
6.3. The Moisture Sensitivity Level(MSL) ......................................................................54
7. Appendix ..........................................................................................................................54
7.1. T erms and Abbreviations ........................................................................................54
7.2. Safety Caution ........................................................................................................57
Table Index
Table 1 : MX680 key features ....................................................................................... 7
Table 2 : Coding schemes and maximum net data rates over air interface .................... 9
Table 3 : Overview of operating modes .......................................................................... 9
Table 4 : MX680 pin assignment ...................................................................................13
Table 5 : Pin description ................................................................................................13
Table 6 : Serial port and USB pin definition ...................................................................27
Table 7 : Serial port characteristics ...............................................................................27
Table 8 : VBUS operation voltage .................................................................................31
Table 9 : SIM pin definition ............................................................................................34
Table 10 : Pin Description of Amphenol SIM Card Holder .............................................36
Table 11 : RI behaviors ..................................................................................................36
Table 12 : Working State of the NETLIGHT ...................................................................38
Table 13 : Pin Definition of the STATUS ........................................................................39
Table 14 : Audio interface definition ...............................................................................42
Table 15 : Microphone input characteristics ..................................................................44
Table 16 : Audio output characteristics ..........................................................................44
Table 17 : Absolute maximum ratings ............................................................................46
Table 18 : Operating Temperature .................................................................................46
Table 19 : Digital interface characteristics .....................................................................47
Table 20 : 3V SIM ..........................................................................................................47
Table 21 : 1.8V SIM .....................................................................................................47
Table 22 : SIM_VDD characteristics ..............................................................................48
Table 23 : VDD_EXT Characteristics ............................................................................48
Table 24 : Current consumption ....................................................................................48
Table 25 : The ESD characteristics (Temperature: 25 ℃, Hum idity: 45 % ) ....................50
Table 26 : GSM850 and EGSM900 conducted RF output power ..................................51
Table 27 : DCS1800 and PCS1900 conducted RF output power ..................................51
Table 28 : Conducted RF receive sensitivity .................................................................52
Table 29 : Operating frequencies ..................................................................................52
Table 30 : Terms and abbreviations ...............................................................................54
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MX680 Hardware Design V2.00
Table 31 : Safety caution ...............................................................................................57
Figure Index
Figure 1 : MX680 functional diagram ............................................................................ 11
Figure 2 : MX680 pin out diagram (Top view) ................................................................12
Figure 3 : Dimensions of MX680 (Unit: mm) .................................................................17
Figure 4 : Recommended PCB footprint outline (U nit : mm) ..........................................18
Figure 5 : Reference circuit of the LDO power supply ...................................................19
Figure 6 : Reference circuit of the DC-DC power supply ...............................................20
Figure 7 : VBAT voltage drop during transmit burst .......................................................20
Figure 8 : The minimal VBAT voltage requirement at VBAT drop ..................................21
Figure 9 : Powered on/down module using transistor ...................................................22
Figure 10 : Powered on/down module using button ......................................................22
Figure 11 : Timing of power on module .........................................................................23
Figure 12 : Timing of power down MX680 by PWRKEY ................................................24
Figure 13 : Connection of the serial interfaces ..............................................................29
Figure 14 : Reference Design for UART Port ................................................................29
Figure 15 : Reference Design for UART Port with Hardware Flow Control ...................30
Figure 16 : USB reference circuit ..................................................................................30
Figure 17 : Connection for software upgrading and debugging .....................................31
Figure 18 : Level Matc h Desi g n for 3. 3V System ..........................................................32
Figure 19 : Level Match Design for 5V System .............................................................33
Figure 20 : Level Match Design for RS-232 ..................................................................33
Figure 21 : Referenc e C ir c ui t for 6-pin SIM Card Holder ...............................................34
Figure 22 : Amphen ol C707 10M006 512 2 SIM Card Holder .......................................36
Figure 23 : RI Behavior of Voice Calling as a Receiver .................................................37
Figure 24 : RI Behavior of Data Calling as a Receiver ..................................................37
Figure 25 : RI Behavior as a Caller ...............................................................................37
Figure 26 : RI Behavior of URC or SMS Received ........................................................38
Figure 27 : Reference Design for NETLIGHT ...............................................................39
Figure 28 : Reference Design for STATUS ....................................................................40
Figure 29 : GSM antenna matching circuit ....................................................................41
Figure 30 : GSM simple antenna matching circuit .........................................................41
Figure 31 : Speaker with amplifier reference circuit.......................................................43
Figure 32 : Speaker reference circuit ............................................................................43
Figure 33 : Earphone reference circuit ..........................................................................44
Figure 34 : Top and bottom view of MX680 ...................................................................53
Figure 35 : Ramp-Soak-Spike Reflow Profile ................................................................54
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MX680 Hardware Design V2.00
Date
Version
Description of change
Author
2013-11-13
1.00
Origin
lihui
2014-05-12
1.10
HD update
lihui
2015-10-10
2.00
HD update
Zhaohaijun

Version History

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MX680 Hardware Design V2.00
Feature
Implementation
Power supply
Single supply voltage: 3.4V~4.4V Typical supply voltage: 4V
Power saving
Typical power consumption in SLEEP mode: 1.1 mA@ DRX=5
0.9 mA@ DRX=9
Frequency bands
Quad-band: GSM850, GSM900, DCS1800, PCS1900 The frequency bands can be set by AT command

1. Introduction

This document describ es MX680 hardware interface in great detail. This document ca n help user to q ui ck l y understand MX680 interface s peci ficatio ns, elec tric al and mechanical details. With the help of this document and other MX680 application notes, user guide, users can use MX680 to design various applications quickly.

2. MX680 Overview

MX680 is a Quad-band GSM/GPRS engine that works at frequencies of GSM850MHz, GSM900MHz,DCS180 0MH z and PCS1900M Hz . The MX680 features GPRS multi-slot class 12 and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4. For more details about GPRS multi-slot classes and coding schemes, please refer to the Appendix B & C.
With a tiny profile of 19.9mm×23.6mm×2.65mm, the module can meet almost all the requirements for M2M applications, including Vehicles and Personal Tracking, Security System, Wireless POS, Industri al PDA, Smart Met eri ng , and R e mot e Maintenance & Control, etc.
MX680 is an SMD type module with LCC package, which can be easily embedded into applications. It provides abundant hardware interfaces like Audio and UART Interface.Designed with power saving technique, the current consumption of MX680 is a s low as 1.1 mA in SLEEP mode when DRX is 5.
MX680 is integrated with Internet service protocols, such as TCP/UDP, FTP and PPP. Extended AT commands have been developed for you to use these Internet service protocols easily.
The module fully complies with the RoHS directive of the European Union.

2.1. MX680 Key Features

Table 1: MX680 key features
●
● The module can search these frequency bands automatically
●
MX680 Hardware Design 7 / 58
Compliant to GSM Phase 2/2+
Transmitting
power
Class 4 (2W)：GSM850、EGSM900 Class 1 (1W)：DCS1800、PCS1900
GPRS
GPRS multi-slot class 12（default） GPRS mobile station class B
Temperature
Normal operation：-35
+80℃
Storage temperature：-45
+90℃
Data GPRS
GPRS data downlink transfer: max. 85.6 kbps
Support Packet Broadcast Control Channel (PBCCH)
USSD ● Unstructured Supplementary Services Data (USSD) support
SMS ● MT, MO, CB, Text and PDU mode
SMS storage: SIM card
SIM interface
Support SIM card: 1.8V, 3V
External antenna
Antenna pad, Bluetooth antenna pad, FM antenna pad
Audio features
Speech codec modes:
Noise Suppression）
Serial port and
Full modem interface with status and control lines, unbalanced,
upgrading firmwar e
USB ● USB_DM and USB_DP
Can be used for debugging and upgrading firmware.
SIM application toolkit
GSM 11.14 Release 99 Real time clock
Support RTC
Timing functions
Use AT command set
Size
19.9*23.6*2.65mm
Weight
2.8g
Firmware upgrade
Main serial port or USB port.
connectivity
range
MX680 Hardware Design V2.00
●
●
●
●
● GPRS multi-slot class 1~12 (option)
●
●
● Restricted operation: -40°C ~ -35°C and +80°C ~ +85°C 1)
●
●
● GPRS data uplink transfer: max. 85.6 kbps
● Coding scheme: CS-1, CS-2, CS-3 and CS-4
● PAP protocol for PPP conn ect
● Integrate the TCP/IP protocol.
●
●
℃ ～
℃ ～
debug port
● Half Rate (ETS 06.20)
● Full Rate (ETS 06.10)
● Enhanced Full Rate (ETS 06.50 / 06.60 / 06.80)
● Adaptive multi rate (AMR)
● Echo Cancellation
●
●
asynchronous.
● 1200bps to 115200bps .
● Can be used for AT commands or data stream.
● Support RTS/CTS hardware handshake and software ON/OFF
flow control.
● Multiplex ability according to GSM 07.10 Multiplexer Protocol.
● Autobauding supports baud rate from 1200 bps to 57600bps.
●
●
Note:When the module works within this temperature range, the deviations from the GSM
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MX680 Hardware Design V2.00
Coding scheme
1 Timeslot
2 Timeslot
4 Timeslot
CS-1:
9.05kbps
18.1kbps
36.2kbps
CS-2:
13.4kbps
26.8kbps
53.6kbps
CS-3:
15.6kbps
31.2kbps
62.4kbps
CS-4:
21.4kbps
42.8kbps
85.6kbps
Mode
Function
Normal
GSM/GPRS
Module will automatically go into sleep mode if the
In this case, the current consumption of module will In sleep mode, the module can still receive paging
message and SMS.
GSM IDLE
Software is active. Module is registered to the GSM network, and the module is ready to communicate.
GSM T ALK
Connection between two subscribers is in progress.
consumption depends on
FR/EFR/HR, hopping sequences, antenna.
GPRS IDLE
The module is not registered to GPRS network. The module is not reachable through GPRS channel.
GPRS
Module is ready for GPRS data transfer, but no data
received. In this case, power
configuration.
GPRS
The PDP context is active, but no data transfer is
e is ready to receive or send GPRS data.
SGSN knows the cell where the module is located at.
GPRS DATA
There is GPRS data transfer (PPP or TCP or UDP) in
power consumption is related
uplink/downlink data rates and GPRS configuration (e.g. Used multi-slot settings).
specification may occur. For example, the frequency error or the phase error will be increased
Table 2: Coding schemes and maximum net data rates over air interface

2.2. Operating Mode

The table below summarizes the various operating modes of MX680.
Table 3: Overview of operating modes
operation
SLEEP
STANDBY
READY
conditions of sleep mode are enabling and there is no on air and no hardware interrupt (such as GPIO interrupt or data on serial port).
reduce to the minimal level.
In this case, the power network settings such as DTX off/on,
is currently sent or consumption depen ds on n et work settings an d GPRS
ongoing. The modul The
MX680 Hardware Design 9 / 58
progress. In this case, with network settings (e.g. power control level);
MX680 Hardware Design V2.00
Power down
Normal power down by sending AT command “AT+QPOWD=1” or
The power management unit shuts down the
is not accessible. Power supply (connected to VBAT) remains applied.
Minimum
A T comma nd “AT+CFUN” can be used t o set t he module to a minimum
without removing the power supply. In this mode,
or the SIM card will not be
umption in this mode is lower
than normal mode.
using the PWRKEY. power supply for the baseband part of the module, and only the po wer supply for the RT C is remained. Software is not active. The serial port
functionality mode
functionality mode the RF part of the module will not work accessible, or both RF part and SIM card will be closed, and the serial port is still accessible. The power cons
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MX680 Hardware Design V2.00
Transceiv
Power Supply
RTC
Turn On
UART
FM
BT

2.3. Functional Diagr a m

The following figure shows a functional diagram of MX680:
● GSM baseband
● GSM RF
● Power management
● Antenna interface
● Other interface
● FM，BT
/Turn off
Audio
Figure 1: MX680 functional diagram
PMU
BaseBand Engine
PA
SIM
GPIO
USB
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MX680 Hardware Design V2.00

3. Package Information

3.1. Pin out Diagram

Figure 2: MX680 pin out diagram (Top view)
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MX680 Hardware Design V2.00
Pin
number
Pin name
I/O Pin
number
Pin name
I/O
1
AGND
2
MIC2P
I 3 MIC2N
I 4
MIC1P
I 5 MIC1N
I 6
SPK1N
O 7 SPK1P
O 8
SPK2N
O 9 SPK1N
O 10
PWRKEY
I
11
RESETB
I 12
STATUS
O
13
NETLIGHT
O 14
USB_DM
I
15
USB_DP
O 16
SIM2_DATA
A
17
SIM2_CLK
A 18
SIM2_VDD
A
19
VDD28
O 20
DTR
I
21
TXD
O 22
RXD
I
23
CTS
O 24
RTS
I
25
DCD/SIM2_RST
O 26
RT O 27
SIM_VDD
O 28
SIM_RST
O
29
SIM_DATA
I/O 30
SIM_CLK
O
31
SIM_GND
32
VRTC
AI
33
VBAT
AI 34
VBAT
AI
35
GND
36
GND
37
GND
38
GND
39
RF_ANT
A 40
GND
41
VBUS
I 42
NC
A
43
D_TXD
O 44
D_RXD
I
45
NC
A 46
ADC
Power supply
Pin name
Pin
I/O
Description
DC
Comment
VBAT
33
AI
Power supply
Vmax=4.4V
Make sure that
rises to 1.6A.
VRTC
32
AI
Power supply for RTC
VImax=VBAT VImin=2.6V
If these pins are unused,
Table 4: MX680 pin assignment

3.2. Pin Description

Table 5: Pin description
number
34
VBAT=3.4V～4.4V
characteristics
Vmin=3.4V Vnorm=4.0V
supply sufficient current in a transmitting burst typically
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MX680 Hardware Design V2.00
VInorm=2.8V
Iin=2.6～5uA
keep open.
VDD28
19 O 2.8V power output
Vmax=2.9V
1.If these pins
add a
when using this
for power
supply.
GND
35，36
40
Ground
Power on/off
Pin name
Pin number
I/O
Description
DC characteristics
Comment
PWRKEY
10 I PWRKEY should
module.
VILmax=
Internally pulled
Reset
Pin name
Pin number
I/O
Description
DC characteristics
Comment
RESETB
11
I/O
Reset inpu
VILmax=0.4V
V
If these pins are
Module Indicator
Pin name
Pin number
I/O
Description
DC characteristics
Comment
STATUS
12 O Indicate module’s Output high level
module turns
low level when module turns off.
VOHmin=
If these pins are
Audio interfaces
Pin name
Pin
I/O
Description
DC
Comment
VOmax=2.85V VOmin=2.6V VOnorm=2.8V Iout(max)=730u A
，
37， 38 ，
be pulled low at least 1 second and then released to power on/down the
Vmin=2.7V Vnorm=2.8V Imax=20mA
0.1*VBAT
VIHmin=
0.6*VBAT
VImax=VBAT
are unused, keep open.
2.Recommend to
2.2~4.7uF Bypass capacitor,
pin
up to VBAT.
MX680 Hardware Design 14 / 58
t(Active low)
operating status. when
on, while output
VIHmin=2.2V Vopenmax=2.8
0.85*VDD_EXT VOLmax=
0.15*VDD_EXT
unused, keep open.
unused,keep open.
number
characteristics
MIC1P
MIC1N
4 5 I
Channel 1 positive and negative voice input
MIC2P
2 3 I
Channel 2 positive and negative voice input
SPK1P
7 6 O
Channel 1 positive and negative voice output
SPK2_P
9 8 O
Channel 2 positive and negative voice
1. Integrate a
ringtone output.
AGND
1 Separate ground
connection for external audio circuits
If these pins are
Network Status Indicator
Pin name
Pin number
I/O
Description
DC characteristics
Comment
NETLIGHT
13 O Network status
VOHmin=
0.15*VDD_EXT
If these pins are
UART Port
Pin name
Pin number
I/O
Description
DC characteristics
Comment
DTR
20 I Data terminal ready
VILmin=-0.3V
0.15*VDD_EXT
If only use TXD, RXD and GND
TXD
21 O Transmit data
RXD
22 I Receive data
CTS
23 O Clear to send
RTS
24 I Request to send
DCD
25 O Data carrier detect
RI
26 O Ring indicator D_TXD
43 O Debug Transmit data
D_RXD
44 I Debug Receive data
USB Port
Pin name
Pin
I/O
Description
DC
Comment
MIC2N
SPK1N
MX680 Hardware Design V2.00
可单路输出
SPK2_N
output
Analog ground ，
indication
0.85*VDD_EXT VOLmax=
Class-AB amplifier internally.
2. Support both Voice and
unused,keep open.
unused,keep open.
MX680 Hardware Design 15 / 58
VILmax=
0.25*VDD_EXT VIHmin=
0.75*VDD_EXT VIHmax= VDD_EXT+0.3 VOHmin=
0.85*VDD_EXT VOLmax=
to communicate, Recommended other pin open
MX680 Hardware Design V2.00
number
characteristics
USB_DM
14
used for debugging and upgrading
VBUS_max=5.
V
If these pins are
USB_DP
15
VBUS
41
I
SIM card interface
Pin name
Pin number
I/O
Description
DC characteristics
Comment
SIM1_VDD
27 O Voltage supply for
SIM card
3V_SIM:
0.9*SIM_VDD
All signals of should be against ESD TVS diode SIM1_RST
28 O SIM1 reset
SIM1_DATA
29
I/O
SIM1 data input/output
SIM1_CLK
30 O SIM1 clock SIM1_GND
31 SIM1 ground
SIM2_DATA
16
I/O
SIM2 data
If these pins are
SIM2_CLK
17 O SIM2 clock
SIM2_VDD
18 O Voltage supply for SIM2 card
SIM2_RST
25 O SIM2 reset
Antenna interface
Pin name
Pin number
I/O
Description
DC characteristics
Comment
RF_ANT
39 Connect GSM antenna
firmware.
SIM1 card. Support 1.8V or 3V
6V VBUS_min=4.4 V VBUS_norm=5
VOLmax=0.36 VOHmin=
0.9*SIM_VDD
1.8V_SIM: VOLmax=
unused,keep open.
SIM interface protected with a array.
unused,keep open.
MX680 Hardware Design 16 / 58
MX680 Hardware Design V2.00

3.3. Package Dimensions

Figure 3: Dimensions of MX680 (Unit: mm)
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MX680 Hardware Design V2.00
Figure 4: Recommended PCB footprint outline (Unit: mm)
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MX680 Hardware Design V2.00

4. Application I nterface

4.1. Power Supply

The power supply range of MX680 is f rom 3.4V to 4. 4V.Recommended voltage is 4.0V.The transmitting burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the VBAT input, a bypass capacitor (low ESR) such as a 100 μF is strongly recommended.
Increase the 33PF and 10PF capacitors can effectively eliminate the high frequency interference. A 5.1V/500mW Zener diode is strongly recommended, the diode can prevent chip from damaging by the voltage surge. These capacitors and Zener diode should be placed as close as possible to MX680 VBAT pins.
The following figure is the reference design of +5V input power supply. The designed output for the power supply is 4.0V, thus a linear regulator can be used.
Figure 5: Reference circuit of the LDO power supply
If there is a high drop-out between the input and the desired output (VBAT), a DC-DC power supply will be preferable because of its better efficiency especially with the 2A peak current in burst mode of the module. The following figure is the reference circuit.
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MX680 Hardware Design V2.00
Figure 6: Reference circuit of the DC-DC power supply
The single 3.7V Li-ion cell battery can be connected to MX680 VBAT pins directly. But the Ni-Cd or Ni-MH battery must be used carefully, since their maximum voltage can rise over the absolute maximum v ol t age of the module and da mage it
When battery is used, the total impedance between battery and VBAT pins should be less than 150mΩ. The following figure shows the VBAT voltage drop at the maximum power transmit phase, and the test condition is as following:
VBAT=4.0V,
A VBAT bypass capacitor CA=100μF tantalum capacitor (ESR=0.7Ω),
Another VBAT bypass capacitor CB=1μF.
Figure 7: VBAT voltage drop during transmit burst
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MX680 Hardware Design V2.00

4.1.1. Power supply pin

Pin 33 and Pin 34 are VBAT input, Pins 36,37,38 are GND of power supply, VRTC pin is power supply of the RTC cicuit in the module.VDD28 output 2.8V when module is in normal operation mode.
When designing the pow er s upply in user’s appli cation, p ay s pecial attention to power loss es. Ensure that the input voltage never drops below 3.1V even when current consumption rises to 2A in the transmit burst. If the power voltage drops below 3.1V, the module may be shut down automatically. The PCB traces from the VBAT pins to the power supply must be wide enough (at least 60mil ) to decreas e vol tage dr ops in th e trans mit burs t. The power IC and th e bypass capacitor should be placed to the module as close as possible.
Figure 8: The minimal VBAT voltage requirement at VBAT drop

4.1.2. Monitoring Power Supply

AT command “AT+CBC” can be used to monitor the VBAT voltage. For detail, please refer to document [1].
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4.2. Power on/down Scenarios

4.2.1. Power on MX680

User can power on MX680 by pulling down the PWRKEY pin for at least 1 second and release. This pin is already pulled up to VBAT in the module internal, so external pull up is not necessary. Reference circuit is shown as below.
Figure 9: Powered on/down module using transistor
Figure 10: Powered on/down module using button
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The power on timing is illustrated as in the following figure.
Figure 11: Timing of power on module
When powe r on procedure is completed, MX680 will send following URC to indicate that the module is ready to operate at fixed baud rate.
RDY This URC does not appear when autobauding function is active.
Note: User can use AT command “AT+IPR=x” to set a fixed baud rate and save the
configuration to non-volatile flash mem or y. After the con fig ur ation is saved as fixed baud rate, the Code “RDY” should be received from the serial port every time when MX680 is powered on. For details, please refer to the chapter “AT+IPR” in document [1].

4.2.2. Power down MX680

MX680 will be powered down in the following situations：
Normal power down procedure: power down MX680 by the PWRKEY pin.。 Normal power down procedure: power down MX680 by AT command “AT+QPOWD=1”. Abnormal power down: over-voltage or under-voltage automatic power down. Abnormal power down: over-temper a tur e or under -temperature automatic power down.
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4.2.2.1. Power down MX680 by the PWRKEY Pin
User can power down MX680 by pulling down the PWRKEY pin for at least 1 s econd and release. Please refer to the power on circuit. The power down timing is illustrated in the following figure.
Figure 12: Timing of power down MX680 by PWRKEY
This procedure makes the mo dule log off from the network and allows the software to enter into a secure state to save data before completely shut down.
Before the completion of the power down procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more, and only the RTC is still active. Power down mode can also be indicated by STATUS pin, which is at low level at this time.
4.2.2.2. Power down MX680 by AT Command
MX680 can be powered down by AT command “AT+QPOWD=1”. This procedure makes the module log off from the network and allows the software to enter into a secure state to save data before completely shut down.
Before the completion of the power down procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more, and only the RTC is still
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MX680 Hardware Design V2.00
, the followi
active. Power down mode can also be indicated by STATUS pin, which is at low level at this time.
For detail about AT command “AT+QPOWD”, please refer to document [1].
4.2.2.3. Over-voltage or Under-voltage Power down
The module software monitors the VBAT voltage constantly. If the voltage ≤ 3.5V, the following URC will be reported:
UNDER-VOLTAGE WARNNING
If the voltage ≥ 4.5V, the following URC will be reported:
OVER-VOLTAGE WARNNING
If the voltag e < 3.3V, the following URC wil l be repor ted, and t he mo dul e wi ll be aut omatic al ly powered down.
UNDER-VOLTAGE POWER DOWN
If the voltag e > 4.6V, the following URC wil l be repor ted, and t he mo dul e wi ll be aut omatic al ly powered down.
OVER-VOLTAGE POWER DOWN
At this moment, AT commands can n ot be ex ecuted any more, an d only the R TC is sti ll activ e. Power down mode can also be indicated by STATUS pin, which is at low level at this time.
4.2.2.4. Over-temperature or Under-temperat ure Power down
The module will constantly monitor the temperature of the module, If the temperature > +80 ℃, the following UR C will be reported:
+CMTE: 1
If the temperature < -30 ℃, the following UR C will be reported:
+CMTE:-1
If the temperature > +85 ℃ automatically powered down.
+CMTE: 2
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, the followi
If the temperature < -40 ℃ automatically powered down.
+CMTE:-2
At this moment, AT commands can n ot be ex ecuted any more, an d only the R TC is sti ll activ e. Power down mode can also be indicated by STATUS pin, which is at low level at this time.
Note：The default temper ature detect is disable, AT command “AT+CMTE” could be used to
read the temperature when the module is running.For details please refer to document [1].

4.3. Power Saving Mode

MX680 has two power saving modes: Minimum functionality mode and sleep mode. AT command“AT+QSCLK=1”can be used to set MX680 into sleep mode. AT command “AT+CFUN=<fun>“ can be used to set MX680 into minimum functionality. When MX680 is in sleep mode and minimum functionality mode, the current of module is lowest.

4.3.1. Minimum Functionalit y Mode

There are three funct ionali ty modes, w hich co uld be set by AT com mand “AT+ CFUN= <fun>“ . The comma nd provides the choice of the functionality levels <fun>=0,1,4.
AT+CFUN=0: Minimum functionality AT+CFUN=1: Full functionality (defaul t) . AT+CFUN=4: Flight mode (disable RF function). Mi ni m um func ti o nal i ty mode
minimizes the current consumption to the lowest level. If MX680 is set to minimum functionality by “AT+CFUN= 0”, the R F func tion and SIM c ar d function will be di sa bl ed. In this case, the serial port is still accessible, but all AT commands correlative to RF function and SIM card function wil l not be accessibl e.
For detailed information about AT command “AT+CFUN=<fun>“, please refer to document [1].

4.3.2. Sleep Mode (AT+QSCLK=1)

User can control MX680 module to enter or exit the sleep mode (AT+QSCLK=1) by DTR signal. When DTR is in high level and without interrupt (on air and hardware such as GPIO interrupt or data in serial port), MX680 will enter sleep mode automatically. In this mode, MX680 can still receive paging or SMS from network but the serial port is not accessible.
Note: Autobauding is default. It cannot enter sleep mode in the absence of synchronous
serial port baud rate after module power on.
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Pin name
Pin number
Function
DTR
20
Data terminal ready
RI
26
Ring indicator
DCD
25
Data carrier detect
CTS
23
Request to send
TXD
21
Transmit data
RXD
22
Receive data
D_TXD
43
Transmit data
D_RXD
44
Receive data
Symbol
Min
Max
Unit
VIL
-0.3
0.7
V
VIH
2.1
3.1
V
VOL
0
0.4
V
VOH
2.4
-
V

4.3.3. Wake Up MX680 from Sleep Mode (AT+QSCLK=1)

When MX680 is in sleep mode (AT+QSCLK=1), the following methods can wake up the module:
Pull down DTR pin. The serial port will be active after DTR pin is pulled to low level for about 50ms.
Receive a voice or data call from network. Receive a SMS from n etwork. Receive external interrupt

4.4. Serial Port and USB Interface

MX680 provides one unbalanced asynchronous serial ports. The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection between module and client (DTE).
Table 6: Serial port and USB pin definition
Serial port
RTS 24 Clear to send
Debug port
Note: Hardware flow control is disable by default. AT command “AT+IFC=2,2”can enable
hardware flow control. AT command “AT+IFC=0,0”can disable hardware flow control. For more details please refer to document [1]
Table 7: Serial port characteristics
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4.4.1. Function of Serial Port

Serial port:
Full mode device. Contains data lines TXD and RXD, hardware flow control lines RTS and CTS, status
lines DTR, DCD and RI.
Serial port can be used for CSD FAX, GPRS service and AT communication. It can also
be used for multiplexing function. For details about multiplexing function, please refer to
table 11. Serial port supports the following baud rates: 1200, 2400, 4800, 9600, 192 00, 38 400, 57600 and 115200bps Autobauding only supports the following baud rates: 1200, 2400, 4800, 9600, 19200, 38400 and 57600bps The default setting is autobauding.
Autobauding allows MX680 to automatically detect the baud rate of the host device. Pay more attention to the following requirements:
Synchronization between DTE and DCE:
When DCE powers on with autobauding enabled, it is recommended to send "AT " or "at" or "aT" or "At" to synchronize the baud rate, until DTE receives the "OK" response, which means DTE and DCE are correctly synchronized. For more information please refer to AT command "AT+IPR".
Restrictions of autobauding operation:
The DTE serial port must be set at 8 data bits, no parity and 1 stop bit. The URC such as "RDY", "+CFUN: 1" and "+CPIN: READY” will not be reported.
Note: User can use AT command “AT+IPR=x” to set a fixed baud rate and the setting will be
saved to non-volatile flash memory automatically. After the configuration is set as fixed baud rate, the URC such as "RDY", "+CFUN: 1" and "+CPIN: READY” will be reported when MX680 is powered on.

4.4.2. Serial Interfaces

The following figure shows the connection between module and client (DTE).
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Figure 13: Connection of the serial interfaces
Three-line connection is shown as below.
Figure 14: Reference Design for UART Port
UART Port with hardware flow control is shown as below. This connection will enhance the reliability of the mass data communication.
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Figure 15: Reference Design for UART Port with Hardware Flow Control

4.4.3. Debug Interface

MX680 could achieve software debug function through USB interface. When powering on the module, connect VBUS,USB_DP,USB_DM, and GND to PC, then install the driver following the prompts, a UART port could be recognized by PC, customer could achieve the software Debug with this UART port.
ZhiwuCom recommen deds the foll owing connected diagram:
Figure 16: USB reference circuit
The TVS on USB data line should be less than 5pf, and traced by differential forms.
Note: please reserve the USB interface or test point for the furth er debugging
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Pin
Min
Typ
Max
Unit
VBUS
4.3
5 7 V
Table 8: VBUS operation voltage

4.4.4. Software Upgrade and Debug

Customer could upgrade module’s firmware through USB or UART interface.
If upgrading through USB port, it is necessary to power on MX680 first, then connect VBUS, USB_DP, USB_DM, a nd GN D to P C. Ther e is no need to operate PWRKEY pin in the whole procedure, when MX680 detects VBUS and could communicate normally with USB_DP and USB_DM, it will enter USB download mode automatically.
Note: When only USB_DP and USB_DM are connected, no VBUS, customer need to pull
down COL0(pin20) before power on the module, then press the PWRKEY button, the module will enter download mode;
If customer upgrades the software through UART port, it is strongly recommended to lead the D_TXD, D_RXD, GND and PWRKEY pin to IO connector for the upgrading, and PWRKEY pin should connect to GND while upgrading. Refer to the following figure for debugging and upgrading software.
Figure 17: Connection for software upgrading and debugging
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The serial port and the debug port support the CMOS level. If user connects the module to the computer, the level shifter should be added between the DCE and DTE.

4.4.4. UART Application

The reference design of 3.3V level match is shown as below. If the host is a 3V system, please change the 5.6K resistor to 10K.
Figure 18: Level Match Design for 3.3V System
The reference design for 5V level match is shown as below. The connection of dotted line can be referred to the connection of solid line. Please pay attention to the direction of signal. Input dotted line o f mo dule sh oul d b e r eferred to input solid l i ne o f t he m odule. Output dott ed line of module should be referred to output solid line of the module.
As to the circuit below, VDD_EXT supplies power for the I/O of module, while VCC_MCU supplies power for the I/O of the peripheral.
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Figure 19: Level Match Design for 5V System
The following circuit shows a reference design for the communication between module and PC. Since the electrical level of module is 2.8V, so a RS-232 level shifter must be used.
Figure 20: Level Match Design for RS-232
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Pin
number
Voltage supply for SIM1 card. Support 1.8V or 3V SIM card
SIM1_RST
28
SIM1 reset
SIM1_ DATA
29
SIM1 data input/output
SIM1_CLK
30
SIM1clock
SIM2_ DATA
17
SIM2 data input/output
SIM2_CLK
18
SIM2 clock
SIM2_VDD
19
Voltage supply for SIM2 card. Support 1.8V or 3V SIM card
SIM2_RST
25
SIM2 reset

4.5. SIM Card Interface

The SIM interfac e complies with the GS M Phase 1 speci fic ati o n a nd t he n ew GSM Phase 2+ specification for FAST 64 kbps SIM card. Both 1.8V and 3.0V SIM card are supported. The SIM interface is powered from an internal regulator in the module.

4.5.1. SIM Card Application

Table 9: SIM pin definition
Pin name
功能
SIM1_VDD 27
The reference circuit for a 6-pin SIM card socket is illustrated as the following figure.
Figure 21: Reference Circuit for 6-pin SIM Card Holder
In order to enhance the rel iabi l i ty and availabil i ty of the SIM card i n appl i cat ion. Please foll ow the below criterion in the SIM circuit design.
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Keep layout of SIM card as close as possible to the module. Assure the possibility of the
length of the trace is less t han 200mm.
Keep SIM card signal away from RF and VBAT alignment. Assure the ground between module and SIM cassette short and wide. Keep the width of
ground no less than 0.5mm to maintain the same electric potential. The decouple
capacitor of SIM_VDD is less than 1uF and must be near to SIM cassette. To avoid cross talk between SIM _DA TA and SIM_CLK . Kee p them aw ay with each o ther
and shield them with surrounded ground In order to offer good ESD protection, it is recommended to add TVS such as WILL
(http://www.willsemi.com/) ESDA6V8AV6. The 22Ω resistors should be connected in series between the module and the SIM card so as to suppress the EMI spurious transmission and enhance the ESD protection. Please to be noted that the SIM peripheral circuit should be close to the SIM card socket.
Place the RF bypass capacitors (33pF) close to the SIM card on all signals line for
improving EMI.

4.5.2.6 Pin SIM Cassette

As to the 6-pin SIM card holder, it is recommended to use Amphenol C707 10M006 512 2. Please visit http://www.amphenol.com for more information.
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Pin
name
Description
C1
SIM_VDD
SIM card power supply
C2
SIM_RST
SIM card reset
C3
SIM_CLK
SIM card clock
C5
GND
Ground
C6
VPP
Not connected
C7
SIM_DATA
SIM card data I/O
State
RI response
Standby
High
Voice call
The pin is changed to low. When any of the following events occur,
Hang up the call
Data call
The pin is changed to low. When any of the following events occur,
Hang up the call
SMS
The pin is changed to low, and kept low for 120ms when a SMS is received. Then it is changed to high.
URC
The pin is changed t o low, and kept low for 120ms when some URCs
changed to high. For more details, please
refer to document [10].
Figure 22: Amphenol C707 10M006 512 2 SIM Card Holder
Table 10: Pin Description of Amphenol SIM Card Holder

4.6. RI Behaviors

Table 11: RI behaviors
the pin will be changed to high:
（1）Establish the call
（2）
the pin will be changed to high:
（1）Establish the call
（2）
are reported. Then it is
NOTE:If URC of SMS is disabled, the RI will not change.
If the module is used as a caller, the RI would maintain high except the URC or SMS is received. On the other hand, when it is used as a receiver, the timing of the RI is shown below.
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Figure 23: RI Behavior of Voice Calling as a Receiver
Figure 24: RI Behavior of Data Calling as a R eceiver
Figure 25: RI Behavior as a Caller
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State
Module function
Off
The module is not running.
64ms On/ 800ms Off
The module is not synchronized with network.
64ms On/ 3000ms Off
The module is synchronized with network.
64ms On/ 300ms Off
The GPRS data transmission after dialing the PPP connection.
Figure 26: RI Behavior of URC or SMS Received

4.7. Network Status Indication

The NETLIGHT pin can be used to drive a network status indication LED. The status of this pin is listed in following table:
Table 12: Working State of the NETLIGHT
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Name
Pin
Description
STATUS
12
Indicate module operating status
A reference circuit is shown as below
.
Figure 27: Reference Design for NETLIGHT

4.8. Operating Status Indication

The STATUS pin is set as an output pin and can be used to judge whether or not module is power-on. In the design, this pin can be connected to a GPIO of DTE or be used to drive an LED in order to judge the module’s operation status. A reference circuit is shown in below.
Table 13: Pin Definition of the STATUS
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Figure 28: Reference Design for STATUS

4.8. Antenna Interface

There are three antenna ports for MX680, GSM antenna port named RF_ANT, Bluetooth antenna port named BT_ANT and FM antenna port named FM_ANT_P/ FM_ANT_N, The RF interface of the three antenna ports has an impedance of 50Ω.
The input impendence of the antenna should be 50Ω, and the VSWR should be less
than 2. It is recommended that the GSM antenna and the BT antenna should be placed as far as possible. The isolations of the three antenna should be bigger than 30db

4.8.1. Antenna Interface

There is a GSM antenna pad named RF_ANT for MX680, the connection of the antenna must be decoupled f rom DC voltage. This is necessary because the antenna connector is DC coupled to ground via an inductor for ESD protection.
The external antenna must be matched properly to achieve best performance, so the matching circuit is necessary, the connection is recommended as following:
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Figure 29: GSM antenna matching circuit
R101，C101，C102 are the matching circuit, the value should be defined by the antenna design. Normally R101 is 0Ω, C101 and C102 are not mounted. The RF connector is used
for conduction test. If the space between RF pin and antenna is not enough, the matching circuit should be designed as in the following figure:
Figure 30: GSM simple antenna matching circuit
Normally R101 is 0Ω, C101 and C102 are not mounted.
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Pin number
Pin Name
I/O
Description
4 5 MIC1P MIC1N
I Channel 1 Microphone input
2 3 MIC2P MIC2N
I
Channel 2 Microphone input
7 6 SPK1P SPK1N
O Channel 1 Audio output
1
AGND
AGND
Form a pseudo-differential pair with SPK2P
8 9 SPK2P SPK2N
O
Channel 2 Audio output
43 44
ER_L ER_R
I
Earphone output

4.9. Audio Interfaces

Table 14: Audio interface definition
SPK1N/P is used for output of the receiver.which can be used as a single-ended channel. SPK2N/P is used for loudspeaker output as it embedded an amplifier of class AB ER_L/P can be used for output of earphone, whi ch can be used as a singl e-ended channe l.
Audio interfaces are all differential input channels. In order to improve audio performance, the following reference circuits are recommended.
The audio signals have to be layout according to differential signal layout rules as shown in following figures.
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4.9.1 Microphone Interfaces Configuration

Figure 31: Speaker with amplifier reference circuit

4.9.2 Speaker Interfaces Configuration

Figure 32: Speaker reference circuit
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Parameter Microphone biasing voltage
1.9
2.2
V
THD <1% at gain = 20 dB; PGA
gain = 14 dB
THD<5%at F=1KHz;
amp gain = 0
dB; PGA gain = 0 dB
Parameter
RL=32Ω THD=0.1%
RL=8Ω
500
850
mW

4.9.3 Earphone Interfaces C onfiguration

Figure 33: Earphone reference circu it

4.9.4 Audio Electronic Characteristic

Table 15: Microphone input characteri stics
Min Typ Max Unit
Working voltage 1.2 1.5 2.0 V Working current 200 - 500 uA Input impedance(differential) 1.2 2.2 KΩ
F=1KHz; pre-amp
SINAD
pre-
Table 16: Audio output characteristics
15.9 mVrms
740 mVrms
Normal output(SPK)
MX680 Hardware Design 44 / 58
Conditions Min Max Max Unit
- 91 - mW
MX680 Hardware Design V2.00
THD=1%
Output swing voltage
4.2 Vpp

4.9.5 TDD

GSM signal could interfere audio by coupling or conducting. Coupling noise could be filtered by adding 33pF and 10pF capacitor over audio lines. 33pF capacitor could eliminate noise from GSM850/EGSM900MHz, while 10pF capacitor could eliminate noise from DCS1800/PCS1900Mhz frequency. Coupling noise should have something to do with PCB layout. Under some scenarios, TDD noise from GSM850/EGSM900MHz frequency affects heavily, but some different story is from DCS1800/PCS1900Mhz frequency, so customer should develop this filter solution according to field test result.
GSM antenna is the key coupling interf ering source of TDD noise. Thereat, pay attention to the layout of audio lines which should be far away from RF cabl e an d ante nna and VB AT pin. The bypass capacitor for filtering should be placed near module and another group need to be placed near to connector.
Conducting noise is mainly caused by the VBAT drop. If audio PA was powered by VBAT directly, then there will be some cheep noise from speaker output easily. So it is better to put big capacitor and ferrite bead near audio PA input.
TDD noise has something to do with GND signal surely. If GND signal issued is not good, lots of high-frequency noises will interfere microphone and speaker over bypass capacitor. So care of good GND during PCB layout nee d to be taken.
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Symbol
Min
Typ
Max
Unit
VBAT
- - 4.5
V
Current
0 - 2.0
A
VBUS
30 V II* - - 8 mA
IO* - - 8 mA
Symbol
Min
Typ
Max
Unit
Normal operation
-35
+25
+80 ℃
Restricted operation:
-40 ~ -35
+80 ~ +85
℃
Storage temperature
-45
+90 ℃

5. Electrical, Rel iability and Radio Characteristics

5.1 Absolute Maximum Ratings

The absolute maximum ratings stated in following table are stress ratings under non-operating conditions. Stresses beyond any of these limits will cause permanent damage to MX680.
Table 17: Absolute maximum ratings
*These para meter s are for dig it al int erf ace pi ns, such as k eyp ad, GPI O, I2C , U ART , LC D an d PCM.

5.2 Operating Temperature

The operating temperature is listed in the following table:
Table 18: Operating Temperature
NOTE:When the module works within this temperature range, the deviation from the GSM
specification may occur. For example, the frequency error or the phase error will be increased.
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Symbol
Parameter
Min
Typ
Max
Unit
VIH
High-level input current
2.1
-
3.1
V
VIL
Low-level input current
-0.3
-
0.7
V
VOH
High-level output voltage
2.4
- - V
VOL
Low-level output voltage
- - 0.4
V
Symbol
Parameter
Min
Typ
Max
Unit
IIH
High-level input current
-1 - 1
mA
IOL
Low-level input current
-1 - 1
mA
VIH
High-level input voltage
2.4 - - V VIL
Low-level input voltage
- - 0.4
V
High-level output
voltage
Low-level output
voltage
Symbol
Parameter
Min
Typ
Max
Unit
IIM
High-level input current
-1 - 1
mA
IOM
Low-level input current
-1 - 1
mA
VIH
High-level input voltage
1.4 - - V VIL
Low-level input voltage
- - 0.27
V
High-level output
voltage
Low-level output
voltage

5.3 Digital Interface Characteristics

Table 19: Digital interface characteristics
*These para meter s are for dig it al int erf ace pi ns, such as k eyp ad, GPI O, I2C , U ART , LC D an d PCM.

5.4 SIM Card Interface

Table 20: 3V SIM
VOH
VOL
Table 21: 1.8V SIM
VOH
VOL
2.7 - - V
- - 0.4 V
1.62 - - V
- - 0.36 V
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Symbol
Parameter
Min
Typ
Max
Unit
-
3.0
- V -
1.8
-
IO
Output voltage
- - 10
mA
Symbol
Parameter
Min
Typ
Max
Unit
VO
Output voltage
2.7
2.8
2.9
V
IO
Output current
- - 50
mA
measured value
Power down mode
133
uA
BS-PA-MFRMS=9
1.6
BS-PA-MFRMS=5
1.7
BS-PA-MFRMS=2
2.6
GSM850
EGSM 900
DCS 1800
PCS1900
PCL=5
235
PCL=1 2
PCL=1 9
PCL=5
275
PCL=1 2
PCL=1 9
DCS180
PCL=0
162
mA

5.5 SIM_VDD Characteristics

Table 22: SIM_VDD characteristics
VO Output voltage

5.6 VDD_EXT Characteristics

Table 23: VDD_EXT Characteristics

5.7 Current Consumption(VBAT=4.0V)

Table 24: Current consumption
Symbol Parameter Conditions
Sleep mode
Idle mode
IVBAT
Average currnet
GSM85 0
Unit
mA
21 mA
105 75
mA
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Voice call
GSM90 0
110 75
mA
MX680 Hardware Design V2.00
0 PCL=7
88
PCL=1 5
PCL=0
145
PCL=7
80
PCL=1 5
PCL=5
506
PCL=1 2
PCL=1 9
PCL=5
605
PCL=1 2
PCL=1 9
PCL=0
328
PCL=7
162
PCL=1 5
PCL=0
306
PCL=7
155
PCL=1 5
PCL=5
215
PCL=1 2
PCL=1 9
PCL=5
256
PCL=1 2
PCL=1 9
PCL=0
155
PCL=7
80
PCL=1 5
PCL=0
145
PCL=7
80
PCL=1 5
Data mode TX)
PCL=5
362
PCL=1 2
70
Data mode GPRS(1RX,4 TX)
PCS190 0
GSM85 0
EGSM 900
DCS 1800
PCS190 0
68
221 115
255 115
98
99
mA
mA
mA
mA
mA
Data mode GPRS(4RX,1 TX)
GPRS(3RX,2
GSM85 0
EGSM 900
DCS 1800
PCS190 0
GSM85 0
95 65
108 68
65
66
145
mA
mA
mA
mA
mA
MX680 Hardware Design 49 / 58
MX680 Hardware Design V2.00
PCL=1 9
PCL=5
428
PCL=1 2
PCL=1 9
PCL=0
245
PCL=7
115
PCL=1 5
PCL=0
225
PCL=7
113
PCL=1 5
I
Peak current
℃, Humidity: 45 % )
Pin name
Contact discharge
Air discharge
VBAT
±5KV
±10KV
GND
±5KV
±10KV
RXD, TXD
±3KV
±6KV
Antenna port
±5KV
±10KV
PWRKEY
±4KV
±8KV
92
EGSM 900
159
mA
95
DCS 1800
mA
83
VBAT-peak
PCS190 0
98
During Tx burst 2
mA
A

5.8 Electro-Static Discharge

MX680 is an ESD sensitive component, so attention should be paid to the procedure of handling and packaging. The ESD test results are shown in the followin g table.
Table 25: The ESD characteristics (Temperature: 25
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GSM850/EGSM 900
Tolerance (dB) for conditions
Normal
Extreme
5
33
±2
±2.5
6
31
±3
±4
7
29
±3
±4
8
27
±3
±4
9
25
±3
±4
11
21
±3
±4
12
19
±3
±4
13
17
±3
±4
14
15
±3
±4
15
13
±3
±4
17 9 ±5
±6
18 7 ±5
±6
19-31 5 ±5
±6
DCS 1800/PCS1900
Tolerance (dB) for conditions
Normal
Extreme
0
30
±2
±2.5
1
28
±3
±4
2
26
±3
±4
3
24
±3
±4
4
22
±3
±4
5
20
±3
±4
6
18
±3
±4

5.9 Radio Characteristics

5.9.1. Module RF Output Power

The following t able sho ws the modul e cond uct ed outp ut p ow er, it is followed by the 3GPP TS
05.05 technical specification requirement.
Table 26: GSM850 and EGSM900 conducted RF output powe r
PCL
Nominal output
ower (dBm)
10 23 ±3 ±4
16 11 ±5 ±6
Table 27: DCS1800 and PCS1900 conducted RF output pow er
PCL
MX680 Hardware Design 51 / 58
Nominal output
ower (dBm)
MX680 Hardware Design V2.00
7
16
±3
±4
8
14
±3
±4
10
10
±4
±5
11 8 ±4
±5
12 6 ±4
±5
13 4 ±4
±5
14 2 ±5
±6
15-28 0 ±5
±6
Receive sensitivity
Typical）
GSM850/EGSM900
-109dBm
-107dBm
DCS1800/PCS1900
-109dBm
-107dBm
Frequency
Receive
Transmit
GSM850
869 ～ 894MHz
824 ～ 849MHz
EGSM900
925 ～ 960MHz
880 ～ 915MHz
DCS1800
1805 ～ 1880MHz
1710 ～ 1785MHz
PCS1900
1930 ～ 1990MHz
1850 ～ 1910MHz
9 12 ±4 ±5

5.9.2. Module RF Receive Sensitivity

The following table shows the module’s conducted receiving sensitivity, it is tested under static condition.
Table 28: Conducted RF receive sensitivity
Frequency
（
＜ ＜
Receive sensitivity(Max)
＜ ＜

5.9.3. Module Operating Frequencies

The following table shows the module’s operating frequency range; it is followed by the 3GPP TS 05.05 technical specification requirement.
Table 29: Operating frequencies
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MX680 Hardware Design V2.00

6. Manufacturing

6.1. Top and Bottom View of MX680

Figure 34: Top and bottom view of MX680
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and rela tive
Abbreviation
Description
ADC
Analog-to-Digital Converter
AMR
Adaptive Multi-Rate

6.2. Typical Solder Reflow Profile

Figure 35: Ramp-Soak-Spike Reflow Profile

6.3. The Moisture Sensitivity Level(MSL)

The moisture sensitivity level of MX680 module is 3. The modules should be mounted within 168 hours after un pac k i ng i n the environmental condit ions of temperature < 30 ℃ humidity of <60% (RH). It is

7. Appendix

7.1. Terms and Abbreviations

Table 30: Terms and abbreviations
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MX680 Hardware Design V2.00
CS
Coding Scheme
CSD
Circuit Switched Data
CTS
Clear to Send
DTE
Data Terminal Equipment (typically computer, terminal, printer)
DTR
Data Terminal Ready
DTX
Discontinuous Trans mi s si on
EFR
Enhanced Full Rate
EGSM
Enhanced GSM
ESD
Electrostatic Discharge
ETS
European Telecommu nic ati on Sta nd ar d
FR
Full Rate
GPRS
General Packet Radio Ser v i c e
GSM
Global Standard for Mobile Communications
IMEI
International Mobile Equipment Identity
HR
Half Rate
MO
Mobile Originated
MS
Mobile Station (GSM engine), also referred to as TE
MT
Mobile Terminated
Li-ion
Lithium-Ion
PAP
Password Authentication Protocol
PBCCH
Packet Broadcast Control Channel
PCL
Power Control Level
PCB
Printed Circuit Board
PCS
Personal Communication System, also referred to as GSM 1900
PDU
Protocol Data Unit
PPP
Point-to-point protocol
RF
Radio Frequency
RMS
Root Mean Square (value)
RTC
Real Time Clock
RX
Receive Direction
SIM
Subscriber Identification Module
SMS
Short Message Service
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MX680 Hardware Design V2.00
TE
Terminal Equipment, al so re ferr ed to as DTE
TX
Transmit Direction
UART
Universal Asynchronous Receiver & Transmitter
URC
Unsolicited Result Code
USSD
Unstructured Supplementary Service Data
Phonebook abbreviati o ns
FD
SIM fix dialing phonebook
LD
SIM last dialing phonebook (list of numbers most recently dialed)
MC
Mobile Equipment list of unanswered MT calls (missed calls)
ON
SIM (or ME) own numbers (MSISDNs) list
RC
Mobile Equipment list of received calls
SM
SIM phonebook
NC
Not connect
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MX680 Hardware Design V2.00
When in a hospital or other health care facility, observe the restrictions about
interference.
Switch off the cellular terminal or mobile before boarding an aircraft. Make
legal action, or both.
Do not operate the cellular terminal or mobile in the presence of flammable
atmospheres can constitute a safety hazard.
Your cellular terminal or mobile receives and transmits radio frequency sets, radios, computers or other electric equipment.
Road safety comes first! Do not use a hand-held cellular terminal or mobile
the vehicle.
GSM cellular terminals or mobiles operate over radio frequency signals and
make or receiv e cal l s, t he cellular terminal or mobile must be switc hed on and
cellular terminal or mobile.

7.2. Safety Caution

Table 31: Safety caution
Marks Requirements
the use of mobiles. Switch the cellular terminal or mobile off, medical equipment may be sensitive to not operate normally for RF energy
sure it is switched off. The operation of wireless appliances in an aircraft is forbidden to prev ent inter ference w ith communication systems. Forget to think much of these instructions may lead to the flight safety or offend against local
gases or fumes. Switch off the cellular terminal when you are near petrol stations, fuel depots, chemical plants or where blasting operations are in progress. Operation of any electrical equipment in potentially explosive
energy while switched on. RF interference can occur if it is used close to TV
when driving a vehicle, unless it is securely mounted in a holder for hands free operation. Befor e making a call with a hand-held terminal or mobile, park
cellular networks and cannot be guaranteed to connect in all conditions, for example no mobile fee or a invali d SIM card. While you are in this condition and need emergent hel p, pleas e remember using emergency calls. In order to
in a service area with adequate cellular signal strength. Some networks do not allow for emergency call if certain network services or phone features are in use (e.g. lock functions, fixed dialing etc.). You may have to deactivate those featur es be for e y ou can make an emergency call. Also, some networks require that a valid SIM card be properly inserted in the
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MX680 Hardware Design V2.00
Contact us:
Shanghai ZhiWu Communication Technology Co.,Ltd Address: R711 Unit B , No. 668, East Beijing Road,Huangpu District, Shanghai, P. R. China 200002 Tel：+86 21 6139 7601
Fax：+86 21 6139 7558 URL： www.zhiwucom.com
MX680 Hardware Design 58 / 58
FCC Notice
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
NOTE 1: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receive r .
-Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
-Consult the dealer or an experienced radio/TV technician for help.
NOTE 2: Any changes or modifications to this unit not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
FCC Radiation Exposure Statement:
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. End users must follow the specific operating instructions for satisfying RF exposure compliance.
Note 1: This module certified that complies with RF exposure requirement under mobile or fixed condition, this module is to be installed only in mobile or fixed applications.
A mobile device is defined as a transmitting device designed to be used in other than fixed locations and to generally be used in such a way that a separation distance of at least 20 centimeters is normally maintained between the transmitter's radiating structure(s) and the body of the user or nearby persons. Transmitting devices designed to be used by consumers or workers that can be easily re-located, such as wireless devices associated with a personal computer, are considered to be mobile devices if they meet the 20 centimeter separation requirement.
A fixed device is defined as a device is physically secured at one location and is not able to be easily moved to another location.
Note 2: Any modifications made to the module will void the Grant of Certification, this module is limited to OEM installation only and must not be sold to end-users, end-user has no manual instructions to remove or install the device, only software or operating procedure shall be placed in the end-user operating manual of final products.
Note 3: Additional testing and certification may be necessary when multiple modules are used.
Note 4: To ensure compliance with all non-transmitter functions the host manufacturer is responsible for ensuring
compliance with the module(s) installed and fully operational. For example, if a host was previously authorized as an unintentional radiator under the Declaration of Conformity procedure without a transmitter certified module and a module is added, the host manufacturer is responsible for ensuring that the after the module is installed and operational the host continues to be compliant with the Part 15B unintentional radiator requirements. Since this may depend on the details of how the module is integrated with the host, LM Technologies Ltd. shall provide guidance to the host manufacturer for compliance with the Part 15B requirements.
Note 5: FCC ID label on the final system must be labeled with “Contains FCC ID: 2AKL7MX680”.
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