Due to the nature of wireless communications, transmission and reception of data can never be
guaranteed. Data may be delayed, corrupted (i.e., have errors) or be totally lost. Although significant
delays or losses of data are rare when wireless devices such as the Sierra Wireless modem are used
in a normal manner with a well-constructed network, the Sierra Wireless modem should not be used
in situations where failure to transmit or receive data could result in damage of any kind to the user or
any other party, including but not limited to personal injury, death, or loss of property. Sierra Wireless
accepts no responsibility for damages of any kind resulting from delays or errors in data transmitted or
received using the Sierra Wireless modem, or for failure of the Sierra Wireless modem to transmit or
receive such data.
Safety and Hazards
Do not operate the Sierra Wireless modem in areas where cellular modems are not advised without
proper device certifications. These areas include environments where cellular radio can interfere such
as explosive atmospheres, medical equipment, or any other equipment which may be susceptible to
any form of radio interference. The Sierra Wireless modem can transmit signals that could interfere
with this equipment. Do not operate the Sierra Wireless modem in any aircraft, whether the aircraft is
on the ground or in flight. In aircraft, the Sierra Wireless modem MUST BE POWERED OFF. When
operating, the Sierra Wireless modem can transmit signals that could interfere with various onboard
systems.
Note: Some airlines may permit the use of cellular phones while the aircraft is on the ground and the door
The driver or operator of any vehicle should not operate the Sierra Wireless modem while in control of
a vehicle. Doing so will detract from the driver or operator’s control and operation of that vehicle. In
some states and provinces, operating such communications devices while in control of a vehicle is an
offence.
is open. Sierra Wireless modems may be used at this time.
Limitations of Liability
This manual is provided “as is”. Sierra Wireless makes no warranties of any kind, either expressed or
implied, including any implied warranties of merchantability, fitness for a particular purpose, or
noninfringement. The recipient of the manual shall endorse all risks arising from its use.
The information in this manual is subject to change without notice and does not represent a
commitment on the part of Sierra Wireless. SIERRA WIRELESS AND ITS AFFILIATES
SPECIFICALLY DISCLAIM LIABILITY FOR ANY AND ALL DIRECT, INDIRECT, SPECIAL,
GENERAL, INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES INCLUDING,
BUT NOT LIMITED TO, LOSS OF PROFITS OR REVENUE OR ANTICIPATED PROFITS OR
REVENUE ARISING OUT OF THE USE OR INABILITY TO USE ANY SIERRA WIRELESS
PRODUCT, EVEN IF SIERRA WIRELESS AND/OR ITS AFFILIATES HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES OR THEY ARE FORESEEABLE OR FOR CLAIMS BY ANY
THIRD PARTY.
Notwithstanding the foregoing, in no event shall Sierra Wireless and/or its affiliates aggregate liability
arising under or in connection with the Sierra Wireless product, regardless of the number of events,
occurrences, or claims giving rise to liability, be in excess of the price paid by the purchaser for the
Sierra Wireless product.
4119272 Rev 2.0 August 16, 2016 2
Product Technical Specification
Patents
This product may contain technology developed by or for Sierra Wireless Inc.
This product includes technology licensed from QUALCOMM
This product is manufactured or sold by Sierra Wireless Inc. or its affiliates under one or more patents
licensed from InterDigital Group and MMP Portfolio Licensing.
Sierra Wireless®, AirPrime®, AirLink®, AirVantage®, WISMO®, ALEOS® and the Sierra Wireless and
Open AT logos are registered trademarks of Sierra Wireless, Inc. or one of its subsidiaries.
Watcher
Windows
Macintosh
countries.
QUALCOMM
Other trademarks are the property of their respective owners.
®
is a registered trademark of NETGEAR, Inc., used under license.
®
and Windows Vista® are registered trademarks of Microsoft Corporation.
®
and Mac OS X® are registered trademarks of Apple Inc., registered in the U.S. and other
®
is a registered trademark of QUALCOMM Incorporated. Used under license.
Contact Information
Sales information and technical support,
including warranty and returns
Corporate and product information
Web: sierrawireless.com/company/contact-us/
Global toll-free number: 1-877-687-7795
6:00 am to 6:00 pm PST
Web: sierrawireless.com
4119272 Rev 2.0 August 16, 2016 3
Product Technical Specification
Document History
Version Date Updates
1.0 May 23, 2016 Creation
Updated:
1.1 May 26, 2016
1.2 May 30, 2016
2.0 August 16, 2016 Updated section 7 FCC Regulations
Table 2 General Features
1.8.2 Regulatory
3.16.2 RF Performances
Table 40.Ordering Information ..................................................................................................... 52
4119272 Rev 2.0 August 16, 2016 9
1. Introduction
This document is the Product Technical Specification for the AirPrime HL7688 Embedded Module. It
defines the high level product features and illustrates the interfaces for these features. This document
is intended to cover the hardware aspects of the product, including electrical and mechanical.
The AirPrime HL7688 belongs to the AirPrime HL Series from Essential Connectivity Module family.
These are industrial grade Embedded Wireless Modules that provide data connectivity on wireless
networks (as listed in Table 1 Supported Bands/Connectivity).
The HL7688 supports a large variety of interfaces such as USB 2.0, UART and GPIOs to provide
customers with the highest level of flexibility in implementing high-end solutions.
Table 1. Supported Bands/Connectivity
RF Band Transmit Band (Tx) Receive Band (Rx) Maximum Output Power
LTE B2 1850 to 1910 MHz 1930 to 1990 MHz 23 dBm (+/- 2dBm) Class 3bis
LTE B4 1710 to 1755 MHz 2110 to 2155 MHz 23 dBm (+/- 2dBm) Class 3bis
LTE B5 824 to 849 MHz 869 to 894 MHz 23 dBm (+/- 2dBm) Class 3bis
LTE B17 704 to 716 MHz 734 to 746 MHz 23 dBm (+/- 2dBm) Class 3bis
UMTS B2 1850 to 1910 MHz 1930 to 1990 MHz 23 dBm (+/- 2dBm) Class 3bis
UMTS B5 824 to 849 MHz 869 to 894 MHz 23 dBm (+/- 2dBm) Class 3bis
1.1. Common Flexible Form Factor (CF3)
The AirPrime HL7688 belongs to the Common Flexible Form Factor (CF3) family of modules. This
family consists of a series of WWAN modules that share the same mechanical dimensions (same
width and length with varying thicknesses) and footprint. The CF
solution to a series of problems faced commonly in the WWAN module space as it:
Accommodates multiple radio technologies (from 2G to LTE advanced) and band groupings
Supports bit-pipe (Essential Module Series) and value add (Smart Module Series) solutions
Offers electrical and functional compatibility
Provides Direct Mount as well as Socketability depending on customer needs
3
form factor provides a unique
1.2. Physical Dimensions
AirPrime HL7688 modules are compact, robust, fully shielded modules with the following dimensions:
Length: 23 mm
Width: 22 mm
Thickness: 2.5 mm
Weight: 3.5 g
Note: Dimensions specified above are typical values.
4119272 Rev 2.0 August 16, 2016 10
Product Technical Specification Introduction
1.3. General Features
The table below summarizes the AirPrime HL7688 features.
Table 2. General Features
Feature Description
Small form factor (146-pad solderable LGA pad) – 23mm x 22mm x
2.5mm (nominal)
Physical
Electrical Single or double supply voltage (VBATT and VBATT_PA) – 3.2V – 4.5V
Release 99 QoS negotiation – Background, Interactive, and
Streaming
Static and Dynamic IP address. The network may assign a fixed IP
address or dynamically assign one using DHCP (Dynamic Host
Configuration Protocol).
Supports PAP and CHAP authentication protocols
PDP context type (IPv4, IPv6, IPv4v6). IP Packet Data Protocol context
RFC1144 TCP/IP header compression
Operating temperature ranges (industrial grade):
Environmental
Class A: -30°C to +70°C
Class B: -40°C to +85°C
RTC Real Time Clock (RTC) with calendar
1.4. Architecture
The figure below presents an overview of the AirPrime HL7688’s internal architecture and external
interfaces.
LGA-
146
VBATT
GND
VGPIO
BAT_RTC
GPIO x 12
UART x 1
Trace Debug (5 pins)
JTAG
26M_CLKOUT
32K_CLKOUT
SIM1
RESET_IN
PWR_ON
USB
ADC x 1
PCM
TX_ON
Memory
(Flash + RAM)
Baseband
MCUDSP
PMURF
Analog Baseband
Peripherals
Dulpexer
X
T
_
RX_LTERF
PA
L
E
T
SAW
Filters
AirPrime HL7688
RFRX_LTE
Antenna
Switch
Antenna
Switch
RF Main
LGA-
146
RF DIV
26MHz
32.768KHz
Figure 1. Architecture Overview
4119272 Rev 2.0 August 16, 2016 13
Product Technical Specification Introduction
1.5. Interfaces
The AirPrime HL7688 module provides the following interfaces and peripheral connectivity:
1x – 8-wire UART
1x – Active Low RESET
1x – USB 2.0
1x – Backup Battery Interface
2x – System Clock Out
1x – Active Low POWER-ON
1x – 1.8V/3V SIM
1x – JTAG Interface
12x – GPIOs (2 of which have multiplexes)
1x – Main Antenna
1x – RX Diversity Antenna
1x – VGPIO
1x – TX_ON
1x – ADC
1x – PCM
1x – Debug Interface
1.6. Connection Interface
The AirPrime HL7688 module is an LGA form factor device. All electrical and mechanical connections
are made through the 146 Land Grid Array (LGA) pads on the bottom side of the PCB.
Figure 2. Mechanical Overview
The 146 pads have the following distribution:
66 inner signal pads, 1x0.5mm, pitch 0.8mm
1 reserved test point (do not connect), 1.0mm diameter
7 test point (JTAG), 0.8mm diameter, 1.20mm pitch
Adding ESD protection is highly recommended at the point where
the USIM contacts are exposed, and for any other signals that
would be subjected to ESD by the user.
1.8. Environmental and Certifications
1.8.1. Environmental Specifications
The environmental specification for both operating and storage conditions are defined in the table
below.
Table 4. Environmental Specifications
Conditions Range
Operating Class A -30°C to +70°C
Operating Class B -40°C to +85°C
Storage -40°C to +85°C
Class A is defined as the operating temperature ranges that the device:
Shall exhibit normal function during and after environmental exposure.
Shall meet the minimum requirements of 3GPP or appropriate wireless standards.
Class B is defined as the operating temperature ranges that the device:
Shall remain fully functional during and after environmental exposure
Shall exhibit the ability to establish an SMS or DATA call (emergency call) at all times even
when one or more environmental constraint exceeds the specified tolerance.
Unless otherwise stated, full performance should return to normal after the excessive
constraint(s) have been removed.
4119272 Rev 2.0 August 16, 2016 15
Product Technical Specification Introduction
1.8.2. Regulatory
The AirPrime HL7688 is compliant with FCC regulations.
FCC compliance will be reflected on the AirPrime HL7688 label.
Table 5. Regulation Compliance
Document Current Version Description
GCF-CC v3.56.1 or later GCF Conformance Certification Criteria
NAPRD.03 V5.22 or later North American Program Reference Document
FCC Part 22, 24, 27 NA Federal Communications Commission
1.8.3. RoHS Directive Compliant
The AirPrime HL7688 module is compliant with RoHS Directive 2011/65/EU which sets limits for the
use of certain restricted hazardous substances. This directive states that “from 1st July 2006, new
electrical and electronic equipment put on the market does not contain lead, mercury, cadmium,
hexavalent chromium, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE)”.
1.8.4. Disposing of the Product
This electronic product is subject to the EU Directive 2012/19/EU for Waste Electrical
and Electronic Equipment (WEEE). As such, this product must not be disposed of at a
municipal waste collection point. Please refer to local regulations for directions on how
to dispose of this product in an environmental friendly manner.
1.9. References
[1] AirPrime HL Series Customer Process Guidelines
Reference Number: 4114330
[2] AirPrime HL7688 AT Commands Interface Guide
Reference Number: TBD
4119272 Rev 2.0 August 16, 2016 16
2. Pad Definition
AirPrime HL7688 pads are divided into 3 functional categories.
Core functions and associated pads cover all the mandatory features for M2M connectivity and will be available by default across all CF
modules. These Core functions are always available and always at the same physical pad locations. A customer platform using only these functions
and associated pads is guaranteed to be forward and/or backward compatible with the next generation of CF
3
modules.
Extension functions and associated pads bring additional capabilities to the customer. Whenever an Extension function is available on a module, it
is always at the same pad location.
Custom functions and associated pads are specific to a given module, and make an opportunistic use of specific chipset functions and I/Os.
Custom features should be used with caution as there is no guarantee that the custom functions available on a given module will be available on
3
other CF
modules.
Other pads marked as “not connected” or “reserved” should not be used.
Table 6. Pad Definition
3
family of
Pad # Signal Name Function I/O
1GPIO1General purpose input/outputI/O
2
3UART1_RTSUART1 Request to sendIL1.8VConnect to test pointCore
4UART1_CTSUART1 Clear to sendOL1.8VConnect to test pointCore
5UART1_TXUART1 Transmit dataI
6UART1_RXUART1 Receive dataO
7UART1_DTR UART1 Data terminal readyIL1.8VConnect to test pointCore
8
UART1_RI /
TRACE_DATA3
UART1_DCD /
TRACE_DATA1
UART1 Ring indicator / Trace data 3O
UART1 Data carrier detect / Trace data 1
OL1.8VConnect to test pointCore / Custom
Active
Low / High
Power Supply
Domain
1.8VLeft OpenExtension
1.8VConnect to test pointCore / Custom
1.8VConnect to test pointCore
1.8VConnect to test pointCore
Recommendation
for Unused Pads
Type
4119272 Rev 2.0 August 16, 2016 17
Product Technical Specification Pad Definition
Pad # Signal Name Function I/O
9
10GPIO2 / TRACE_DATA2 General purpose input/output / Trace data 2I/O
65GPIO4General purpose input/outputI/OH1.8VLeft Open Extension
66GPIO5General purpose input/outputI/O
67-70GNDGroundGND
Power supply (refer to section 3.1 Power
Supply for more information)
Power supply (refer to section 3.1 Power
Supply for more information)
I
I
Active
Low / High
Power Supply
Domain
0V
1.8VLeft Open Extension
1.8VLeft Open Extension
1.8VLeft Open Extension
1.8VLeft Open Extension
3.2V (min)
3.7V (typ)
4.5V (max)
3.2V (min)
3.7V (typ)
4.5V (max)
3.2V (min)
3.7V (typ)
4.5V (max)
1.8VLeft Open Extension
0V
Recommendation
for Unused Pads
Mandatory
connection
Mandatory
connection
Left Open Not connected
Left Open Not connected
Left Open Not connected
Left Open Not connected
Mandatory
connection
Mandatory
connection
Mandatory
connection
Mandatory
connection
Type
Core
Core
Core
Core
Core
Core
Core
4119272 Rev 2.0 August 16, 2016 20
Product Technical Specification Pad Definition
Pad # Signal Name Function I/O
71 - 166
167 - 234 GND Ground GND 0V Core
236JTAG_RESETJTAG RESETIL1.8VLeft Open Extension
237JTAG_TCKJTAG Test ClockI
238JTAG_TDOJTAG Test Data OutputO
239JTAG_TMSJTAG Test Mode SelectI
240JTAG_TRSTJTAG Test ResetIL1.8VLeft Open Extension
241JTAG_TDIJTAG Test Data InputI
242JTAG_RTCKJTAG Returned Test ClockO
Note: These pads are not available on the AirPrime HL7688 module.
Active
Low / High
Power Supply
Domain
1.8VLeft Open Extension
1.8VLeft Open Extension
1.8VLeft Open Extension
1.8VLeft Open Extension
1.8VLeft Open Extension
Recommendation
for Unused Pads
Type
4119272 Rev 2.0 August 16, 2016 21
Product Technical Specification Pad Definition
2.1. Pad Configuration (Top View, Through Module)
Figure 3. Pad Configuration
4119272 Rev 2.0 August 16, 2016 22
3. Detailed Interface Specifications
Note: If not specified, all electrical values are given for VBATT=3.7V and an operating temperature of
25°C.
For standard applications, VBATT and VBATT_PA must be tied externally to the same power
supply. For some specific applications, AirPrime HL7688 modules support separate VBATT and
VBATT_PA connection if requirements below are fulfilled.
3.1. Power Supply
The AirPrime HL7688 modules is supplied through the VBATT signal with the following
characteristics.
Table 7. Power Supply
Supply Minimum Typical Maximum
VBATT voltage (V) 3.2* 3.7 4.5
VBATT_PA voltage (V) Full Specification 3.2* 3.7 4.5
VBATT_PA voltage (V) Extended Range 2.8 3.7 4.5
* This value has to be guaranteed during the burst.
Note: Load capacitance for VBATT is around 32µF ± 20% embedded inside the module.
Load capacitance for VBATT_PA is around 10µF ± 20% embedded inside the module.
3.2. Current Consumption
The following table lists the current consumption of the AirPrime HL7688 at different conditions.
Note: The following data is with USB disconnected to achieve the lowest current consumption. An
Table 8. Current Consumption
Parameter Minimum Typical Maximum Unit
Off mode 95 110 202 µA
Sleep mode – LTE
DRX = 1.28s
USB = disconnected
additional 0.6mA will be consumed if USB is connected.
Typical values are defined for VBATT/VBATT_PA at 3.7V and 25°C, for 50Ω impedance at all RF
ports. Maximum values are provided for VSWR3:1 with worst conditions among supported ranges
of voltages and temperature.
The AirPrime HL7688 module provides an input/output to connect a Real Time Clock power supply.
This pad is used as a back-up power supply for the internal Real Time Clock. The RTC is supported
when VBATT is available but a back-up power supply is needed to save date and hour when VBATT
is switched off.
If VBATT is available, the back-up battery can be charged by the internal 1.8V power supply regulator.
Table 11. BAT_RTC Electrical Characteristics
Parameter Minimum Typical Maximum Unit
Input voltage - 1.8 - V
Input current consumption - 2.5 (TBC) - µA
Output voltage -5% 1.8 +5% V
Max charging current (@VBATT=3.7V) - 25 - mA
Note: When used with the HL Series snap-in socket, or when compatibility with HL6528x is needed,
Sierra Wireless recommends adding a 10µF capacitor to the BAT_RTC pad.
3.5. SIM Interface
The AirPrime HL7688 has one physical SIM interface, UIM1, which has optional support for dual SIM
application with an external SIM switch.
The UIM1 interface allows control of a 1.8V/3V SIM and is fully compliant with GSM 11.11
recommendations concerning SIM functions.
The five signals used by this interface are as follows:
UIM1_VCC Power-up Setting
Time (µs) from power down
- 2.9 -
- 1.80 -
- - 50 At Iout_Max
- 10 -
The appropriate output voltage
is auto detected and selected by
software.
Max output current in sleep
mode = 3 mA
3.5.1. UIM1_DET
UIM1_DET is used to detect and notify the application about the insertion and removal of a SIM
device in the SIM socket connected to the SIM interface. When a SIM is inserted, the state of
UIM1_DET transitions from logic 0 to logic 1. Inversely, when a SIM is removed, the state of
UIM1_DET transitions from logic 1 to logic 0.
3.6. USB
The AirPrime HL7688 has one USB interface.
Table 14. USB Pad Description
Pad Number Signal Name I/O Function
12 USB_D- I/O USB Data Negative
13 USB_D+ I/O USB Data Positive
16 USB_VBUS I USB VBUS
Note: When the 5V USB supply is not available, connect USB_VBUS to VBATT to supply the USB
interface.
3.7. Electrical Information for Digital I/O
The AirPrime HL7688 supports two groups of digital interfaces with varying current drain limits. The
following list enumerates these interface groupings and the following table enumerates the electrical
characteristics of each digital interface.
The main serial link (UART1) is used for communication between the AirPrime HL7688 module and a
PC or host processor. It consists of a flexible 8-wire serial interface that complies with RS-232
interface.
The supported baud rates of the UART1 are 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600,
115200, 230400, 460800, 500000, 750000, 921600, 1843200, 3000000 and 3250000 bit/s.
The signals used by UART1 are as follows:
TX data (UART1_TX)
RX data (UART1_RX)
Request To Send (UART1_RTS)
Clear To Send (UART1_CTS)
Data Terminal Ready (UART1_DTR)
Data Set Ready (UART1_DSR)
Data Carrier Detect (UART1_DCD)
Ring Indicator (UART1_RI)
Note: Signal names are according to PC view.
UART1 pad description is summarized in the table below.
Table 17. UART1 Pad Description
Pad # Signal Name* I/O* Description
2 UART1_RI O Signal incoming calls (data only), SMS, etc.
3 UART1_RTS I Request to send
4 UART1_CTS O AirPrime HL7688 is ready to receive AT commands
5 UART1_TX I Transmit data
6 UART1_RX O Receive data
7 UART1_DTR I (active low)
8 UART1_DCD O Signal data connection in progress
9 UART1_DSR O Signal UART interface is ON
* According to PC view.
Prevents the AirPrime HL7688 from entering sleep mode,
switches between data mode and command mode, and
wakes the module up.
3.10. POWER-ON Signal (PWR_ON_N)
A low level signal has to be provided to switch the AirPrime HL7688 module ON.
It is internally connected to the permanent 1.8V supply regulator inside the HL7688 via a pull-up
resistor. Once VBAT is supplied to the HL7688 module, this 1.8V supply regulator will be enabled and
so the PWR_ON_N signal is by default at high level.
The PWR_ON_N signal’s characteristics are listed in the table below.
Power-up period (ms) from PWR_ON_N falling edge 2000 - -
PWR_ON_N assertion time (ms) 25
Note: As PWR_ON_N is internally pulled up with 47kΩ, an open collector or open drain transistor must be
used for ignition.
VGPIO is an output from the module that can be used to check if the module is active.
When VGPIO = 0V, the module is OFF
When VGPIO = 1.8V, the module is ON (it can be in idle, communication or sleep mode)
Note: PWR_ON_N signal cannot be used to power the module off. To power the module off, use AT
command AT+CPWROFF.
3.11. Reset Signal (RESET_IN_N)
To reset the module, a low level pulse must be sent on the RESET_IN_N pad for 20ms. This action
will immediately restart the AirPrime HL7688 module with the PWR_ON_N signal at low level. (If the
PWR_ON_N signal is at high level, the module will be powered off.) As RESET_IN_N is internally
pulled up, an open collector or open drain transistor has to be used to control this signal.
The RESET_IN_N signal will reset the registers of the CPU and reset the RAM memory as well, for
the next power on.
Note: As RESET_IN_N is referenced to the VRTC (200kΩ pull-up resistor to VRTC 1.8V) an open
Table 19. RESET_IN_N Electrical Characteristics
collector or open drain transistor has to be used to control this signal.
Parameter Minimum Typical Maximum
Input Voltage-Low (V) - 0.51
Input Voltage-High (V) 1.33 - 2.2
Reset assertion time (ms) 20 - -
Power-up period (ms) from RESET_IN_N falling edge* 2000 - -
One Analog to Digital Converter input, ADC1, is provided by the AirPrime HL7688 module. This
converter is a 10-bit resolution ADC ranging from 0 to 1.2V.
The following table describes the pad description of the ADC interface.
Table 20. ADC Interface Pad Description
Pad NumberSignal NameI/ODescription
24 ADC1 I Analog to digital converter
Typical ADC1 use is for monitoring external voltage; wherein an application is used to safely power
OFF an external supply in case of overvoltage.
Table 21. ADC Electrical Characteristics
Parameter Minimum Typical Maximum Remarks
ADC1 Resolution (bits) - 10 -
Input Voltage Range (V) 0 - 1.2 General purpose input
Update rate per channel (kHz) - - 125
Integral Nonlinearity (bits) - - ±2 LSB
Offset Error (bits) - - ±1 LSB
Gain 849 853 858
Input Resistance (MΩ) 1 - -
Input Capacitance (pF) - 1 -
3.13. Clock Interface
The AirPrime HL7688 module supports two digital clock interfaces.
The following table describes the pad description of the clock out interfaces.
Table 22. Clock Interface Pad Description
Pad Number Signal Name I/O I/O Type Description
22 26M_CLKOUT O 1.8V 26MHz Digital Clock output
23 32K_CLKOUT O 1.8V 32.768kHz Digital Clock output
Enabling or disabling the clock out feature can be done using AT commands. For more information
about AT commands, refer to document [2] AirPrime HL7688 AT Commands Interface Guide.
The Digital Audio (PCM) Interface allows connectivity with standard audio peripherals. It can be used,
for example, to connect an external audio codec.
The programmability of this interface allows addressing a large range of audio peripherals.
The signals used by the Digital Audio Interface are as follows:
PCM_SYNC: The frame synchronization signal delivers an 8 kHz frequency pulse that
synchronizes the frame data in and the frame data out.
PCM_CLK: The frame bit clock signal controls data transfer with the audio peripheral.
PCM_OUT: The frame “data out” relies on the selected configuration mode.
PCM_IN: The frame “data in” relies on the selected configuration mode.
The PCM interface is a high speed full duplex interface that can be used to send and receive digital
audio data to external audio ICs. The Digital Audio Interface also features the following:
PCM master or slave
16 bits data word length, linear mode
MSB first
Configurable PCM bit clock rate on 256kHz, 384kHz or 512kHz
Long frame sync
The following table describes the pad description of the PCM interface.
Table 23. PCM Interface Pad Description
Pad NumberSignal NameI/ODescription
33 PCM_OUT O PCM data out
34 PCM_IN I PCM data in
35 PCM_SYNC I/O PCM sync out
36 PCM_CLK I/O PCM clock
Refer to the following table for the electrical characteristics of the digital audio interface.
The AirPrime HL7688 module provides a signal, TX_ON, for TX indication. The TX_ON is a 2.3V
signal and its status signal depends on the module transmitter state.
Refer to the following table for the status of the TX_ON signal depending on the embedded module’s
state.
Table 31. TX_ON Indicator Pad Description
Pad Number Signal Name Function I/O Type Power Supply Domain
Apply a LOW level logic to the PWR_ON_N pad (pad 59); within approximately 25ms, VGPIO will
appear to be at 1.8V. Either UART1 or the USB interface could be used to send AT commands. The
AT command interface is available in about 7 seconds after PWR_ON_N for either UART1 or USB.
When using UART1, the AT command interface is available after the transition of UART1_CTS from
high to low level.
When using a USB connection, the HL7688 will start communicating with the host after USB
enumeration. The time when AT commands can be sent will depend on the initialization time on the
USB host.
Figure 9. PWR_ON_N Sequence with VGPIO Information
Note: As PWR_ON_N is internally pulled up with 47kΩ, an open collector or open drain transistor must be
The PWR_ON_N pad has the minimum assertion time requirement of 25ms, with LOW active. Once
the valid power on trigger is detected, the PWR_ON_N pad status can be left open.
The maximum inrush current is 1.3 A and lasts less than 1.5 ms.
4119272 Rev 2.0 August 16, 2016 39
used for ignition.
Product Technical Specification Design Guidelines
5.2. Module Switch-Off
AT command AT+CPWROFF enables the user to properly switch the AirPrime HL7688 module off.
Figure 10. Power OFF Sequence for PWR_ON_N, VGPIO
Note: PWR_ON_N is internally pulled up by 47kΩ to 1.8V.
5.3. Emergency Power OFF
If required, the module can be switched off by controlling the RESET_IN_N pad (pad 11). This must
only be used in emergency situations if the system freezes (not responding to AT commands).
To perform an emergency power off, a low level pulse must be sent on the RESET_IN_N pad for
20ms while the PWR_ON_N signal is inactive (high level). This action will immediately shut the
HL7688 module down and the registers of the CPU and RAM memory will be reset for the next power
on.
5.4. Sleep Mode Management
5.4.1. Using UART1
AT command AT+KSLEEP enables sleep mode configuration.
AT+KSLEEP=0:
The module is active when DTR signal is active (low electrical level).
When DTR is deactivated (high electrical level), the module enters sleep mode after a while.
On DTR activation (low electrical level), the module wakes up.
AT+KSLEEP=1
:
The module determines when it enters sleep mode (when no more tasks are running).
“0x00” character on the serial link wakes the module up.
AT+KSLEEP=2
4119272 Rev 2.0 August 16, 2016 40
:
Product Technical Specification Design Guidelines
The module never enters sleep mode.
5.4.2. Using USB
Use AT+KSLEEP=1 to allows the module to automatically enter sleep mode while the USB interface is
in use.
5.5. Power Supply Design
The AirPrime HL7688 module should not be supplied with voltage over 4.5V even temporarily or
however briefly.
If the system’s main board power supply unit is unstable or if the system’s main board is supplied with
over 4.5V, even in the case of transient voltage presence on the circuit, the module’s power amplifier
may be severely damaged.
To avoid such issues, add a voltage limiter to the module’s power supply lines so that VBATT and
VBATT_PA signal pads will never receive a voltage surge over 4.5V. The voltage limiter can be as
simple as a Zener diode with decoupling capacitors as shown in the diagram below.
Figure 11. Voltage Limiter Example
5.6. ESD Guidelines for SIM Card
Decoupling capacitors must be added according to the drawings below as close as possible to the
SIM card connectors on UIM1_CLK, UIM1_RST, UIM1_VCC, UIM1_DATA and UIM1_DET signals to
avoid EMC issues and to comply with the requirements of ETSI and 3GPP standards covering the
SIM electrical interface.
A typical schematic including SIM detection is provided below.
4119272 Rev 2.0 August 16, 2016 41
Product Technical Specification Design Guidelines
Figure 12. EMC and ESD Components Close to the SIM
5.7. ESD Guidelines for USB
When the USB interface is externally accessible, it is required to have ESD protection on the
USB_VBUS, USB_D+ and USB_D- signals.
Figure 13. ESD Protection for USB
Note: It is not recommended to have an ESD diode with feedback path from USB_VBUS to either
Sierra Wireless recommends using a 90Ω DLP0NSN900HL2L EMC filter and an RCLAMP0503N or
ESD5V3U2U-03LRH ESD diode.
4119272 Rev 2.0 August 16, 2016 42
USB_D+ or USB_D-.
6. Reliability Specification
AirPrime HL7688 modules are tested against the Sierra Wireless Industrial Reliability Specification
defined below.
6.1. Reliability Compliance
The AirPrime HL7688 module connected on a development kit board application is compliant with the
following requirements.
Table 33. Standards Conformity
AbbreviationDefinition
IEC International Electro technical Commission
ISO International Organization for Standardization
6.2. Reliability Prediction Model
6.2.1. Life Stress Test
The following tests the AirPrime HL7688 module’s product performance.
The AirPrime HL7688 module has been granted modular approval for mobile applications. Integrators
may use the HL7688 module in their final products without additional FCC certification if they meet the
following conditions. Otherwise, additional FCC approvals must be obtained.
1. At least 20 cm separation distance between the antenna and the user’s body must be
maintained at all times.
2. To comply with FCC regulations limiting both maximum RF output power and human
exposure to RF radiation, the maximum antenna gain including cable loss in a mobile-only
exposure condition must not exceed:
9.01 dBi in Band 2
6.00 dBi in Band 4
10.41 dBi in Band 5
9.74 dBi in Band 17
3. The HL7688 module must not transmit simultaneously with other collocated radio transmitters
within a host device.
4. The RF signal must be routed on the application board using tracks with a 50Ω characteristic
impedance. Basically, the characteristic impedance depends on the dielectric, the track width
and the ground plane spacing. In order to respect this constraint, Sierra Wireless
recommends using MicroStrip or StripLine structure and computing the Tracks width with a
simulation tool (like AppCad shown in the figure below and that is available free of charge at
http://www.agilent.com).
4119272 Rev 2.0 August 16, 2016 50
Product Technical Specification FCC Regulations
If a multi-layered PCB is used, the RF path on the board must not cross any signal (digital,
analog or supply).
If necessary, use StripLine structure and route the digital line(s) "outside" the RF structure. An
example of proper routing is shown in the figure below.
Stripline and Coplanar design requires having a correct ground plane at both sides.
Consequently, it is necessary to add some vias along the RF path. It is recommended to use
Stripline design if the RF path is fairly long (more than 3cm), since MicroStrip design is not
shielded. Consequently, the RF signal (when transmitting) may interfere with neighbouring
electronics (AF amplifier, etc.). In the same way, the neighbouring electronics (microcontrollers, etc.) may degrade the reception performances. The antenna connector is
intended to be directly connected to a 50Ω antenna and no matching is needed.
5. A label must be affixed to the outside of the end product into which the HL7688 module is
incorporated, with a statement similar to the following:
This device contains FCC ID:
N7NHL7688
6. A user manual with the end product must clearly indicate the operating requirements and
conditions that must be observed to ensure compliance with current FCC RF exposure
guidelines.
The end product with an embedded HL7688 module may also need to pass the FCC Part 15
unintentional emission testing requirements and be properly authorized per FCC Part 15.
Note: If this module is intended for use in a portable device, you are responsible for separate approval to
satisfy the SAR requirements of FCC Part 2.1093.
4119272 Rev 2.0 August 16, 2016 51
8. Ordering Information
Table 40. Ordering Information
Model Name Description Part Number
HL7688 HL7688 embedded module Contact Sierra Wireless for the latest SKU
DEV-KIT HL Series Development Kit 6000620
4119272 Rev 2.0 August 16, 2016 52
9. Terms and Abbreviations
Abbreviation Definition
ADC Analog to Digital Converter
AGC Automatic Gain Control
AT Attention (prefix for modem commands)
CDMA Code Division Multiple Access
CF3 Common Flexible Form Factor
CLK Clock
CODEC Coder Decoder
CPU Central Processing Unit
DAC Digital to Analog Converter
DTR Data Terminal Ready
EGNOS European Geostationary Navigation Overlay Service
EMC Electromagnetic Compatibility
EMI Electromagnetic Interference
EN Enable
ESD Electrostatic Discharges
ETSI European Telecommunications Standards Institute
FDMA Frequency-division multiple access
GAGAN GPS aided geo augmented navigation
GLONASS Global Navigation Satellite System
GND Ground
GNSS Global Navigation Satellite System
GPIO General Purpose Input Output
GPRS General Packet Radio Service
GSM Global System for Mobile communications
Hi Z High impedance (Z)
IC Integrated Circuit
IMEI International Mobile Equipment Identification
I/O Input / Output
LED Light Emitting Diode
LNA Low Noise Amplifier
MAX Maximum
MIN Minimum
MSAS Multi-functional Satellite Augmentation System
N/A Not Applicable
PA Power Amplifier
PC Personal Computer
PCB Printed Circuit Board
PCL Power Control Level
PLL Phase Lock Loop
PWM Pulse Width Modulation
QZSS Quasi-Zenith Satellite System
4119272 Rev 2.0 August 16, 2016 53
Product Technical Specification Terms and Abbreviations
Abbreviation Definition
RF Radio Frequency
RFI Radio Frequency Interference
RMS Root Mean Square
RST Reset
RTC Real Time Clock
RX Receive
SCL Serial Clock
SDA Serial Data
SIM Subscriber Identification Module
SMD Surface Mounted Device/Design
SPI Serial Peripheral Interface
SW Software
PSRAM Pseudo Static RAM
TBC To Be Confirmed
TBD To Be Defined
TP Test Point
TX Transmit
TYP Typical
UART Universal Asynchronous Receiver-Transmitter
UICC Universal Integrated Circuit Card
USB Universal Serial Bus
UIM User Identity Module
VBATT Main Supply Voltage from Battery or DC adapter
VSWR Voltage Standing Wave Ratio
WAAS Wide Area Augmentation System
4119272 Rev 2.0 August 16, 2016 54
Loading...
+ hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.