Sagem HILO APPLICATION NOTE User Manual
HILO V2 APPLICATION NOTE
~ Freedom of speech
for smart machines ~
This page is intentionally left blank
FICHE RECAPITULATIVE / REVISION HISTORY
Ed Date
Date
1 02/24/2010 URD1 OTL 5635.2 007 72335 ed 01 Document creation
2
3
4
5
Référence
Reference
Pages modifiées /
Changed pages
Observations
Comments
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 3/58
SOMMAIRE / CONTENTS
1. OVERVIEW...................................................................................................................................................................7
1.1 OBJECT OF THE DOCUMENT......................................................................................................................... 7
1.1 REFERENCE DOCUMENTS .............................................................................................................................7
1.2 MODIFICATION OF THIS DOCUMENT .......................................................................................................... 7
1.3 CONVENTIONS ...................................................................................................................................................7
2. BLOCK DIAGRAM....................................................................................................................................................... 8
3. FUNCTIONAL INTEGRATION................................................................................................................................... 9
3.1 HOW TO CONNECT TO A SIM CARD .......................................................................................................... 10
3.2 HOW TO CONNECT THE AUDIOS? .............................................................................................................12
3.2.1 Connecting microphone and speaker .....................................................................................................12
3.2.2 Recommended characteristics for the microphone and speaker........................................................14
3.2.3 DTMF OVER GSM NETWORK ...............................................................................................................15
3.3 PWM ....................................................................................................................................................................15
3.3.1 PWM outputs ..............................................................................................................................................15
3.3.2 PWM for Buzzer connection .....................................................................................................................15
3.4 NETWORK LED .................................................................................................................................................16
3.5 POWER SUPPLY ..............................................................................................................................................16
3.5.1 Burst conditions.......................................................................................................................................... 17
3.5.2 Ripples and drops ......................................................................................................................................17
3.6 EXAMPLE OF POWER SUPPLIES ................................................................................................................18
3.6.1 DC/DC Power supply from a USB or PCMCIA port..............................................................................18
3.6.2 Simple high current low dropout voltage regulator................................................................................ 18
3.6.3 Simple 4V boost converter. ......................................................................................................................19
3.7 UART ................................................................................................................................................................... 19
3.7.1 Signals reminder ........................................................................................................................................19
3.7.2 Complete V24 – connection HiLo V2 - host ...........................................................................................20
3.7.3 Complete V24 interface with PC .............................................................................................................. 21
3.7.4 Partial V24 (RX-TX-RTS-CTS) – connection HiLo V2 - host............................................................... 22
3.7.5 Partial V24 (RX-TX) – connection HiLo V2 - host .................................................................................23
3.8 UART0 .................................................................................................................................................................24
3.9 GPIO ....................................................................................................................................................................25
3.10 ADC.................................................................................................................................................................. 25
3.11 PCM .................................................................................................................................................................25
3.12 RF BURST INDICATOR ............................................................................................................................... 26
3.13 BACKUP BATTERY ......................................................................................................................................26
3.13.1 Backup battery function feature ...............................................................................................................26
3.13.2 Current consumption on the backup battery .......................................................................................... 26
3.13.3 Charge by internal HiLo V2 charging function .......................................................................................27
3.13.4 Backup Battery technology .......................................................................................................................27
3.14 START THE MODULE PROPERLY AND AVOID POWER UP ISSUES ..............................................28
3.14.1 Power domains...........................................................................................................................................28
3.14.2 IO DC presence before power ON. .........................................................................................................30
3.14.3 Side effects of a retro supply (current re-injection) ...............................................................................30
3.14.4 Example of a Current re-injection on U.A.R.T. ......................................................................................30
3.14.5 AdviCes for every power domain.............................................................................................................32
3.14.6 CASE OF VBAT RISE TIME ....................................................................................................................32
3.14.7 Start- up.......................................................................................................................................................32
3.15 UART SIGNALS AT POWER ON................................................................................................................33
3.16 POWER ON AND SLEEP DIAGRAMS ......................................................................................................35
3.17 MODULE RESET...........................................................................................................................................37
3.18 MODULE SWITCH OFF ............................................................................................................................... 37
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 4/58
3.19 SLEEP MODE MANAGEMENT AND POWER CONSUMPTION .......................................................... 38
4. RECOMMENDED I/OS AND COMPONENTS ON THE FINAL PRODUCT .........................................................40
5. ESD & EMC RECOMMENDATIONS .......................................................................................................................41
5.1 HILO V2 ALONE ................................................................................................................................................41
5.2 HANDLING THE MODULE ..............................................................................................................................41
5.3 CUSTOMER’S PRODUCT WITH HILO V2....................................................................................................41
5.3.1 Analysis ....................................................................................................................................................... 41
5.3.2 Recommendations to avoid ESD issues ................................................................................................41
6. RADIO INTEGRATION..............................................................................................................................................42
6.1 ANTENNA ...........................................................................................................................................................42
6.2 GROUND LINK AREA....................................................................................................................................... 43
6.3 LAYOUT ..............................................................................................................................................................44
6.4 MECHANICAL SURROUNDING .....................................................................................................................45
6.5 OTHER RECOMMENDATIONS – TESTS FOR PRODUCTION/DESIGN ............................................... 45
7. AUDIO INTEGRATION .............................................................................................................................................45
7.1 MECHANICAL INTEGRATION AND ACOUSTICS ......................................................................................45
7.2 ELECTRONICS AND LAYOUT .......................................................................................................................46
8. RECOMMENDATIONS ON LAYOUT OF CUSTOMER’S BOARD ......................................................................46
8.1 GENERAL RECOMMENDATIONS ON LAYOUT......................................................................................... 46
8.1.1 Ground.........................................................................................................................................................46
8.1.2 Power supplies ........................................................................................................................................... 46
8.1.3 Clocks ..........................................................................................................................................................47
8.1.4 Data bus and other signals .......................................................................................................................47
8.1.5 Radio............................................................................................................................................................ 47
8.1.6 Audio............................................................................................................................................................47
8.2 EXAMPLE OF LAYOUT FOR CUSTOMER’S BOARD................................................................................48
9. LABEL .........................................................................................................................................................................48
10. REFERENCE DESIGN: HiLo V2 DEVELOPMENT KIT...................................................................................... 49
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 5/58
FIGURES LIST
Figure 1: Block diagram of Hilo V2 module ............................................................................................................................ 8
Figure 2: HiLo V2 40 pins industrial connector front side .......................................................................................................9
Figure 3: HiLo V2 back side .................................................................................................................................................... 9
Figure 4: SIM Card signals..................................................................................................................................................... 10
Figure 5: Protections: EMC and ESD components close to the SIM .....................................................................................10
Figure 6: Protections: Serial resistors for long SIM bus lines. ...............................................................................................11
Figure 7: Audio connection .................................................................................................................................................... 12
Figure 8 : Filter and ESD protection of microphone ..............................................................................................................12
Figure 9: Filter and ESD protection of 32 ohms speaker........................................................................................................13
Figure 10: Example of D class TPA2010D1 1Watt audio amplifier connections. ................................................................. 13
Figure 11: Buzzer connection .................................................................................................................................................15
Figure 12: Network LED connection ..................................................................................................................................... 16
Figure 13: Over voltage protection on VBatt ......................................................................................................................... 16
Figure 14: GSM/GPRS Burst Current rush ............................................................................................................................ 17
Figure 15: GSM/GPRS Burst Current rush and VBAT drops and ripples ...............................................................................17
Figure 16: Example of power supply based on a DC/DC step down converter......................................................................18
Figure 17: Example of power supply based on regulator MIC29302WU ..............................................................................18
Figure 18: Example with Linear LT1913 ............................................................................................................................... 19
Figure 19: Complete V24 connection between HiLo V2 and host .........................................................................................20
Figure 20: CTS versus POK_IN signal during the power on sequence. .................................................................................20
Figure 21: connection to a data cable .....................................................................................................................................21
Figure 22: Example of a connection to a data cable with a MAX3238E................................................................................ 22
Figure 23: Partial V24 connection (4 wires) between HiLo V2 and host ...............................................................................22
Figure 24: CTS versus POK_IN signal during the power on sequence. .................................................................................23
Figure 25: Partial V24 connection (2 wires) between HiLo V2 and host ...............................................................................23
Figure 26: CTS versus POK_IN signal during the power on sequence. .................................................................................24
Figure 27: PCM interface timing ............................................................................................................................................25
Figure 28: RF_TX burst indicator ..........................................................................................................................................26
Figure 29: Backup battery or 10µ F Capacitor internally charged ..........................................................................................27
Figure 30: Charging curve of backup battery ......................................................................................................................... 27
Figure 31 : HiLo V2 40 pins with their power domains ......................................................................................................... 29
Figure 32: Digital Pin-out clamp diode .................................................................................................................................. 31
Figure 33: Hardware interface diodes solution between HiLo V2 and host ...........................................................................31
Figure 34: Hardware interface buffers solution between HiLo V2 and host .......................................................................... 31
Figure 35: Power ON sequence ..............................................................................................................................................33
Figure 36: Full UART signals during the power on sequence................................................................................................34
Figure 37: Diagram for the power on ..................................................................................................................................... 35
Figure 38: Diagram for the sleep mode ..................................................................................................................................36
Figure 39: Reset command of the HiLo V2 by an external GPIO .......................................................................................... 37
Figure 40: Power supply command by a GPIO ......................................................................................................................37
Figure 41: Power OFF sequence for POK_IN, VGPIO and CTS...........................................................................................38
Figure 42: Power consumption at DRX9 (with RS-NGMO2 power supply) ......................................................................... 39
Figure 43: Antenna connection...............................................................................................................................................42
Figure 44: Antenna detection circuit ......................................................................................................................................42
Figure 45: How to ground HiLo to customer board .......................................................................................................... 43
Figure 46: Connection of RF lines with different width.........................................................................................................44
Figure 47: Layout of audio differential signals on a layer n ...................................................................................................47
Figure 48: Adjacent layers of audio differential signals .........................................................................................................47
Figure 49: layer allocation for a 6 layers circuit ..................................................................................................................... 48
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 6/58
1. OVERVIEW
1.1 OBJECT OF THE DOCUMENT
The aim of this document is to describe some examples of hardware solutions for developing products around
the Sagemcom HiLo V2 GPRS Module. Most parts of these solutions are not mandatory. Use them as
suggestions of what should be done to have a working product and what should be avoided thanks to our
experiences.
This document suggests how to integrate the HiLo V2 GPRS module in machine devices such as automotive,
AMM (Automatic Metering Management), tracking system: connection with external devices, layout advice,
external components (decoupling capacitors…).
1.2 REFERENCE DOCUMENTS
URD1 OTL 5635.2 013 72398 ed 01 - HiLo V2 technical specification
URD1 OTL 5635.1 008 70248 - AT Command Set for SAGEM HiLo Modules
1.3 MODIFICATION OF THIS DOCUMENT
The information presented in this document is supposed to be accurate and reliable. Sagemcom assumes no
responsibility for its use, nor any infringement of patents or other rights of third parties which may result from its
use.
This document is subject to change without notice.
Changes or modifications not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
1.4 CONVENTIONS
SIGNAL NAME : All signal name available on the pads of the HiLo V2 module is written in italic.
Specific attention must be granted to the information given here.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 7/58
2. BLOCK DIAGRAM
Figure 1: Block diagram of Hilo V2 module
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 8/58
3. FUNCTIONAL INTEGRATION
The improvement of Silicon technologies heads toward functionality improvement, less power consumption. The
postage stamp sized HiLo V2 module meets all these requirement, uses the last high end technology in a very
compact design of only 27 x 27 x 3.6 mm and weighs less than 3 grams.
All digital I/Os among the 40 Pins connector are in 2.8V domain which is suitable for most systems except
SIM I/O's which can also be in the 1.8V domain depending on the used SIM card and POK_IN at 3Vdomain
Analogical I/Os are in the following power domains
• VSIM (the SIM I/Os at 1.8V or 2.9V domain).
• VBACKUP 3V domain
• VGPIO 2.8V domain
• VBAT (from 3.2V to 4.5V domain)
• AUX_ADC0 2.8V domain
• INTMIC_P 2.85V domain
• HSET_OUT_P/N VBAT domain
• ANTENNA (RF power Amplifier is on VBAT domain)
Do not power the module I/O with a voltage over the specified limits, this could damage the module.
Acoustic engineering competences are mandatory to get accurate audio performance on customer’s
product.
Radio engineering competences are mandatory to get accurate radio performance on customer’s product.
Figure 2: HiLo V2 40 pins industrial connector front side
Figure 3: HiLo V2 back side
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 9/58
3.1 HOW TO CONNECT TO A SIM CARD
Figure 4: SIM Card signals
HiLo V2 module provides the SIM signals on the 40 Pins connector. A SIM card holder with 6 pads needs to be
adopted to use the SIM function.
Decoupling capacitors have to be added on SIM_CLK, SIM_RST, VSIM and SIM_DATA signals as close
as possible to the SIM card connector to avoid EMC issues and pass the SIM card tests approvals .
Use ESD protection components to protect SIM card and module I/Os against Electro Static Discharges.
The following schematic shows how to protect the SIM access for 6 pads connector, this should be apply
every time a SIM card holder is accessible by the final customer.
Figure 5: Protections: EMC and ESD components close to the SIM
In case of long SIM bus lines over 10cm, it is recommended to also use serial resistors to avoid electrical
overshoots on SIM bus signals. Use 56Ω for the clock line and 10Ω for the reset and data lines.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 10/58
Figure 6: Protections: Serial resistors for long SIM bus lines.
The schematic here above includes the hardware SIM card presence detector. It can be connected to any GPIO
and managed with an AT command.
SIM card must not be removed from its holder while it is still powered. First switch the module off properly
with the AT command, then remove the SIM card from its holder.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 11/58
3.2 HOW TO CONNECT THE AUDIOS?
The HiLo V2 module features one input audio path and one output audio path. The input path is single-end
while the output path is differential. In this following chapter examples of design will be given including
protections against EMC and ESD and some notes about the routing rules to follow to avoid the TDMA noise
sometimes present in this sensitive area of design.
customer’s product.
Note that acoustic engineering competences are mandatory to get accurate audio performance on
3.2.1 Connecting microphone and speaker
The HiLo V2 module can manage an external microphone (INTMIC_P) in single-end mode and an external
speaker (HSET_OUT_P / HSET_OUT_N) in differential mode. Thus, one speaker and one microphone can be
connected to the module. The 2.4V voltage to bias the microphone is implemented in the module.
The speaker connected to the module should be 32 ohms.
HiLo V2
If the design is ESD or EMC sensitive we strongly recommend reading the notes below.
A poor audio quality could either come from the PCB routing and placement or from the chosen components (or even
both).
3.2.1.1 Notes for microphone
HSET_OUT_P
HSET_OUT_N
INTMIC_P
Filter and
ESD
protection
Figure 7: Audio connection
32ohms speaker
MIC
Pay attention to the microphone device, it must not be sensitive to RF disturbances.
If you need to have deported microphone out of the board with long wires, you should pay attention to the
EMC and ESD effect. It is also the case when your design is ESD sensitive. In those cases, add the
following protections to improve your design.
voltage to be re-injected inside the module.
To ensure proper operation of such sensitive signals, they have to be isolated from the others by
analogue ground on customer’s board layout. (Refer to Layout design chapter)
HiLo V2
To use an external bias voltage for the microphone, simply use a capacitor of 10µF to prevent this bias
INTMIC_P
Figure 8 : Filter and ESD protection of microphone
Ferrite Bead
MIC
18pF
ESD protection
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 12/58
3.2.1.2 Notes for speaker
As explained for the microphone, if the speaker is deported out of the board or is sensitive to ESD, use the
schematic here after to improve the audio.
18pF
HiLo V2
HSET_OUT_P, HSET_OUT_N tracks must be larger than other tracks: 0.1 mm.
As described in the layout chapter, differential signals have to be routed in parallel (HSET_OUT_P and
HSET_OUT_N signals)
The impedance of audio chain (filter + speaker) must be lower than 32Ω.
To use an external audio amplifier connected to a loud-speaker, use serial capacitors of 10nF on HiLoNC
audio outputs to connect the audio amplifier.
HSET_OUT_P
HSET_OUT_N
Figure 9: Filter and ESD protection of 32 ohms speaker
Ferrite Bead
Ferrite Bead
18pF
ESD protection
speaker
ESD protection
Figure 10: Example of D class TPA2010D1 1Watt audio amplifier connections.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 13/58
3.2.2 Recommended characteristics for the microphone and speaker
3.2.2.1 Recommended characteristics for the microphone
Item to be inspected Acceptance criterion
Sensitivity - 40 dB SPL +/-3 dB (0 dB = 1 V/Pa @ 1kHz)
Frequency response Limits (relatives values)
Freq. (Hz) Lower limit Upper limit
100 -1 1
200 -1 1
300 -1 1
1000 0 0
2000 -1 1
3000 -1.5 1.5
3400 -2 2
4000 -2 2
Current consumption 1 mA (maximum)
Operating voltage DC 1 to 3 V (minimum)
S / N ratio 55 dB minimum (A-Curve at 1 kHz, 1 Pa)
Directivity Omni-directional
Maximum input sound pressure level 100 dB SPL (1 kHz)
Maximum distortion 1%
Radio frequency protection Over 800 -1200 MHz and 1700 -2000 MHz, S/N ratio 50
dB minimum (signal 1 kHz, 1 Pa)
3.2.2.2 Recommended characteristics for the speaker
Item to be inspected Acceptance criterion
Input power: rated / max 0.1W (Rate)
Audio chain impedance 32 ohm +/- 10% at 1V 1KHz
Frequency Range
300 Hz ~ 4.0 KHz
Sensitivity (S.P.L) >105 dB at 1KHz with IEC318 coupler,
Distortion 5% max at 1K Hz, nominal input power
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 14/58
3.2.3 DTMF OVER GSM NETWORK
Former systems used to transmits data through DTMF modulation on RTC telephone lines.
Audio DTMF tones are not guarantee over GSM network
This is due to the nature of the GSM Voice CODEC - it is specifically designed for the human voice and does
not faithfully transmit DTMF.
When you press the buttons on your GSM handset during a call, this goes in the Signalling channel - it does not
generate in-band DTMF; the actual DTMF tones are generated in the network.
Therefore if your design needs the DTMF functionality, you should know their transmission over the network is
not at all guaranteed (because of voice codec). This could work or fail depending very strongly to the GSM
network provider. Sagemcom does not guarantee any success on using this function.
However tests on HiLo V2 shown this feature can work on some GSM Networks. Successful transmissions and
receptions have been done with 300ms of characters duration and 200mVpp as input level on microphone
input.
If this function is needed, first try with your network and those parameters then (if success) try to tune
them to fit your specification.
3.3 PWM
3.3.1 PWM outputs
The HiLo V2 module can manage two PWM outputs.
They can be configured with appropriate AT command (for more details refer to AT command set for
Sagemcom HiLo V2 module specification).
User application can set for each output:
• Frequency between : 25.6KHz and 1083.3KHz
• Duty range from: 0 to 100%
3.3.2 PWM for Buzzer connection
The HiLo V2 module can manage a dedicate PWM output to drive a buzzer. The buzzer can be used to alarm
for abnormal state.
Resistors should be added to protect the buzzer. The value of these resistors depends on the buzzer and
the transistor. Normally, they can be set as 1KΩ.
VBAT
Hilo V2
PWM2
R2
R1
Figure 11: Buzzer connection
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 15/58
3.4 NETWORK LED
The HiLo V2 module can manage a network LED. The LED can be connected either to one of the available
GPIO or to a PWM (but not the one dedicated to the buzzer).
The transistors can be found a in a single package referenced as UMDXX or PUMDXX Family.
Value of resistor R depends on characteristic of chosen LED; it is used to limit the current through the diode.
Use the AT command to set the GPIO or PWM used to control the LED.
GPIO or
PWM
HiLo V2
VBAT
R
Figure 12: Network LED connection
3.5 POWER SUPPLY
The HiLo V2 module can be supplied by a battery or any DC/DC converter compliant with the module supply
range 3.2V to 4.5V and 2.2 A.
WARNING:
The HiLo V2 module is not supposed to be supplied with a voltage over 4.5V even in transient.
However the module can resist to over voltage transient lower than 6.8V.
If the system main board power supply unit is not stable or if the system main board is supplied with 9V
or over, in case of transient voltage presence on the circuit, the HiLo V2 module power amplifier may be
severely damaged.
To avoid such issue, simply add a voltage limiter to the module power supply lines so the VBATT signal Pins
may never receive a surge voltage over 6.8V. The limiter can be as simple as a Zener diode as shown here
under or in the annex development kit schematic of this document.
Figure 13: Over voltage protection on VBatt
The PCB tracks must be well dimensioned to support 2.2 A maximum current (Burst current 1.8A plus the
extra current for the other used I/Os). The voltage ripple caused by serial resistance of power supply path
(Battery internal resistance, tracks and contact resistance) could result in the voltage drops.
To prevent any issue in the power up procedure the typical rise time for VBAT should be 1ms.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 16/58
The HiLo V2 module does not manage the battery charging.
3.5.1 Burst conditions
- Communication mode (worst case: 2 continuous GSM time-slot pulse):
Figure 14: GSM/GPRS Burst Current rush
A 47µF with Low ESR capacitor is highly recommended for VBAT and close to the module Pins1,2 & 39,40.
3.5.2 Ripples and drops
Current burst at 1.8A 33dBm
GSM TX Lev 5
Ripple
VBAT drop
3.2V Min
Figure 15: GSM/GPRS Burst Current rush and VBAT drops and ripples
The minimum voltage during the drop of VBAT must be 3.2V at 33dBm at Pins1,2,39 & 40 for the full range
of the required functioning temperature. To reach this aim, adapt the VBAT tracks width to minimize the loss:
the shorter and thicker is the track, the lower is the serial impedance.
To check the serial resistor, any CAD software can be used or by experiment by measuring it on the PCB by
injecting 1A into the VBAT track on connector side and shorting to GND the other side, this could be done using
a laboratory power supply set to few volts with a limitation in current to 1A. Then the measure of the drop
voltage leads to the serial resistor.
Noise on VBAT due to drops could result in poor audio quality.
Serial resistor should be less than 250mΩ including the impedance of connectors if any.
Ripple has to be minimised to have a clean RF signal. This can be improved by filtering the output of the
power supply when AC/DC or DC/DC components are used. Refer to the power converter chip supplier
application note for more information and advises.
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 17/58
To have 3.7V out R1=560K & R2=271.8K
(270K+1.8K)
3.6 EXAMPLE OF POWER SUPPLIES
3.6.1 DC/DC Power supply from a USB or PCMCIA port.
It the following application note from Linear Technology LTC3440, this schematic is an example of a DC/DC
power supply able to power 3.6V under 2A. This can be use with a AC/DC 5V unit or an USB or PCMCIA bus as
input power source. C6 to C9 can be followed by a serial MOS transistor to avoid a slow rise signal at VOUT.
Figure 16: Example of power supply based on a DC/DC step down converter
3.6.2 Simple high current low dropout voltage regulator.
If the whole power consumption is not an issue, this example of a simple voltage regulator preceded by an
AC/DC to 5V converter, can be use to power the module.
The voltage output is given by:
VOUT = 1.235V × [1 + (R1 / R2)]
Figure 17: Example of power supply based on regulator MIC29302WU
Note d’étude / Technical document :
URD1– OTL 5635.2– 007 / 72335 Edition 01
HiLo V2 Application Note
15 March 2011 - Page 18/58
Loading...