sim300 an deskphone design v1.02

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SIM300

Deskphone design

Application Note

SIMCOM Ltd,.

21th

Dec 2005


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SIM300 deskphone design

Confidential SIMCOM

Document Name: SIM300 deskphone design

Version: 01.02

Date: 2005-12-21

Doc Id: SIM300_AN_01_V1.02

Status: Release

General Notes

Simcom offers this information as a service to its customers, to support application and

engineering efforts that use Simcom products. The information provided is based upon

requirements specifically provided to Simcom by the customers. Simcom has not undertaken any

independent search for additional relevant information, including any information that may be in

the customers possession. Furthermore, system validation of this Simcom product within a larger

electronic system remains the responsibility of the customer or the customers system integrator.

All specifications supplied herein are subject to change.

Copyright

This document contains proprietary technical information which is the property of SIMCOM

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

damages. All rights reserved in the event of grant of a patent or the registration of a utility model

or design. All specification supplied herein are subject to change without notice at any time.

Copyright SIMCOM Limited. 2005

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SIM300_AN_01_V1.02 Page 3 of 12

Contents

Contents ............................................................................................................................................3

Version History.................................................................................................................................4

1 Introduction....................................................................................................................................5

2 Product concept..............................................................................................................................5

3Description of design ..................................................................................................................5

31Description of the power supply ...................................................................................5

32Reference design of power on circuit............................................................................7

33Reference design of SIM card circuit............................................................................7

34Reference design of the audio circuit............................................................................8

35Reference design of the I/O circuit .............................................................................10

36Reference design of layout..........................................................................................10

37Reference design of the PCB ......................................................................................11

38Reference design of the circuit diagram......................................................................12

Figure Index

FIGURE 1VBAT INPUT......................................................................................................................6

FIGURE 2VBAT VOLTAGE DROP AT THE TRANSMIT PHASE...................................................6

FIGURE 3POWER ON CIRCUIT................................................................. ...................................... 7

FIGURE 4REFERENCE CIRCUIT OF 8PIN SIM CARD.................................................................. 8

FIGURE 5REFERENCE CIRCUIT OF 6PIN SIM CARD.................................................................. 8

FIGURE 6MICROPHONE CIRCUIT ........................................................... ...................................... 9

FIGURE 7AUDIO CIRCUIT LAYOUT................................................................... ........................... 9

FIGURE 8REFERENCE PCB ABOUT THE AUDIO TRACE......................................................... 10

FIGURE 9BLOCK FIGURE OF THE SIM300....................................................... .......................... 11

FIGURE 10REFERENCE FIGURE OF CONNECTOR LAYOUT .................................................. 11

FIGURE 11REFERENCE LAYOUT OF PCB................................................................................... 12


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Version History

Data Version Description of change Author

2005-08-04 01.00 Origin anthony

2005-12-05 01.01 Add the power on circuit anthony

2005-12-21 01.02 Add the serial port and software upgrade anthony


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SIM300_AN_01_V1.02 Page 5 of 12

1 Introduction

This document describes the design reference of the SIMCOM SIM300 module that used to

design for deskphone. The document mainly is about design notes, reference circuit and PCB

layout reference .

Reference document:

SIM300_HD_V1.05(051122)

2 Product concept

Designed for global market, SIM300 is a Tri-band GSM/GPRS engine that works on frequencies

EGSM 900 MHz, DCS 1800 MHz and PCS1900 MHz. SIM300 provides GPRS multi-slot class

10 capability and support the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.

With a tiny configuration of 40mm x 33mm x 2.85 mm , SIM300 can fit almost all the space

requirement in your application, such as Smart phone, PDA phone and other mobile device.

The physical interface between SIM300 and the mobile application is through a 60 pins

board-to-board connector, which provides all hardware interfaces from module to customers

boards except the RF antenna interface.

z The keypad and SPI LCD interface will give you the flexibility to develop customizedapplications.

z Two serial ports can help you easily develop your applications.z Two audio channels include two microphones inputs and two speaker outputs. These

audio interfaces can be easily configured by AT command.

z One ADC inputz Two GPIO ports and SIM card detection port

3 Description of design

3 1 Description of the power supply

The power supply of SIM300 is from a single voltage source of VBAT= 3.4V...4.5V. In some

case, the ripple in a transmit burst may cause voltage drops when current consumption rises to

typical peaks of 2A, So the power supply must be able to provide sufficient current up to 2A.For the VBAT input, a local bypass capacitor is recommended. A capacitor (about 100F, low


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ESR) is recommended. Multi-layer ceramic chip (MLCC) capacitors can provide the best

combination of low ESR and small size but may not be cost effective. A lower cost choice may be

a 100 F tantalum capacitor (low ESR) with a small (1 F to 10F) ceramic in parallel, which is

illustrated as following figure. And the capacitors should put as closer as possible to the SIM300

VBAT pins. The following figure is the recommended circuit.

Figure 1 VBAT input

The following figure is the VBAT voltage ripple wave at the maximum power transmit phase,

the test condition is VBAT=4.0V, VBAT maximum output current =2A, CA=100 F tantalum

capacitor (ESR=0.7) and CB=4.7F.B

Figure2 VBAT voltage drop at the transmit phase

Note:

Because of the large current consumption at the transmit phase, the trace width is too thin may

cause the voltage drop when PCB layout, that:

1. Power supply may be larger than 2A.

2. The power supply trace length may be as short as possible, trace width as wide as possible

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3 2 Reference design of power on circuit

You can turn on the module by driving the PWRKEY to a low level voltage for period time.

The automatic power on circuit illustrate as following figure. The PWRKEY pin is the NO.34 pin

of the module interface. The value of the capacitor C155 is recommended as 330uF/16V. The

diode D21N4148is used for current discharge when power down. The diode can be modified to

the other type part which discharge capability is better. You can make a decision by some

experiments yourself.

Figure 3 power on circuit

3 3 Reference design of SIM card circuit

Following is the reference circuit about SIM interface. We recommend an electrostatic discharge

device ST (www.st.com ) ESDA6V1W5 or ON SEMI (www.onsemi.com ) SMF05C for ESD

ANTI. The resistances (R204-R206) showed in the figure 3 should be added in series in the IO

line between the module and the SIM card for matching the impedance. The SIM_PRESENCE pin

is used for detecting the SIM card removal.

Note: the pull up resistance R207 must be added.

You can select the 8 pins SIM card. The reference circuit about SIM card illustrates as following

figure.

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Figure 4 Reference circuit of 8PIN SIM card

If you dont use the SIM card detection function, you can let the SIM_PRESENCE pin NC or

connect to the GND. The reference circuit about 6 pins SIM card illustrates as following figure.

Figure 5 Reference circuit of 6PIN SIM card

3 4 Reference design of the audio circuit

The peripheral microphone power supply circuit used in the SIM100S peripheral circuit can be

deleted in SIM300. Because it has put internal to SIM300 for reduce the customs BOM.you can

connect the microphone directly to the MIC pin by differential mode or single-ended mode. Thereference circuit is showed as the following figure.

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Figure 6 Microphone circuit

The differential trace is recommended to reduce the RF noise when the audio trace layout, such

as the following figure. The analogy GND and the digital GND must be divided. The audio filter

should be put nearest the input part. Please refer to the white flag in the following figure.

Figure 7Audio circuit layout

The differential trace is recommended about microphone trace, because the microphone sign

is so weakly and its anti-interference is so bad. The trace width is recommended 0.2mm and be

surrounded with analogy GND. Please refer to the following figure, the blue part is digital GND

and the gray part is analogy GND in the bottom layer. The more digital GND should be put in

the top layer.

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Figure 8 Reference PCB about the audio trace

3 5 Reference design of the I/O circuit

Because the IO level of the SIM300 is 3.0V, please note the matching level between the

customer IO and the SIM300 IO.

About the serial port and software upgrade

The TXDRXDDBG_TXDDBG_RXDGND must be connected to the IO connector

when user need to upgrade software and debug softwane,the TXDRXD should be used for

software upgrade and the DBG_TXDDBG_RXD for software debug. The PWRKEY pin is

recommended to connect to the IO connector; the user also can add a switch between the

PWRKEY and the GND. The PWRKEY should be connected to the GND when SIM300 isupgrading software. Please refer to SIM300_HD_V1.05 for the detail.

3 6 Reference design of layout

The block of the SIM300 module is showed as the following figure. Please keep away from

the RF part and the antenna when layout the audio trace. The top layer had better few trace and put

the more digital GND. The underside of the module in top copper layer should show the copper,

because the cover of the SIM300 can be connected to GND better. Please refer to the figure 9, the

blue part is GND, the red part is trace in the top layer, the green part is trace in the bottom layer.The audio trace should be shielded by GND.

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Figure 9 Block figure of the SIM300

Top layer Bottom layer

Figure 10 Reference figure of connector layout

3 7 Reference design of the PCB

The layout of the PCB may affect the total capability of the SIM300. Please refer to the

following figure, the white block is the module, the gray block is the power supply and the

peripheral circuit, the blue block is the audio circuit, the yellow block is peripheral circuit, thebrown block is GND copper. The brown block should be put fewer trace, and the trace may be put

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in the bottom layer. Please note the isolation between the audio circuit and the digital circuit, and

add the more via between the top layer and the bottom layer.

Figure 11Reference LAYOUT of PCB

3 8 Reference design of the circuit diagram

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1 MCR03EZPJ220 22R(0603) 3 R304,R305,R306

2 MCR03EZPJ101 100R(0603) 16 R104,R307-R316,R320-R324

3 MCR03EZPJ471 470R(0603) 2 R103,R319

4 MCR03EZPJ222 2.2K(0603) 1 R317

5 MCR03EZPJ103 10K(0603) 3 R204,R302,R318

6 MCR03EZPJ203 20K(0603) 4 R201,R202,R203,R205

7 MCR03EZPJ433 43K(0603) 1 R101

8 MCR03EZPJ104 100K(0603) 4 R102,R301,R303,R326

9 C1608COG1H100D(TDK) 10pF(0603) 1 C206

10 C1608COG1H220D(TDK) 22pF(0603) 34 C104,C201,C202,C211-C225,C227,C304,

C310-C324

C1608COG1H330J(TDK)CM105CG330J10AT

12 C1608X7R1H104K(TDK) 100nF(0603) 11 C102,C106-C110,C208,C210,C303,C306,C3

13 CM105X7R224K10AT 220nF(0603) 1 C309

14 CM105X7R394K10AT 390nF(0603) 2 C203,C204

15 1uF(0603) 1 C207

16 T491V107M010AS 100uF 3 C103,C209,C305

17 330uF 1 C301

18 1000uF 1 C101

19 2200uF 1 C302

20 39nH 1 L202

21 100nH 4 L203,L204,L205,L20622 10uH 1 L201

23 MIC29302BT 1 U101

24 SMF05CT1 ESD 1 FV301

25 SP3243ECA(SSOP28) 1 U102

26 LM4890MM 1 U201

27 1SS400-TE61 1 D301

28 1 T301

: _SIM300 PCBV1.03

BOM _SIM300_PCBA_BOM BOM

C20511 33pF(0603) 1

-SIM300 PCBABOM


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29 60PIN( 1 U301

30 C707-10M006-512-2U SIM 1 X302

31 D-SUB 9M RS232 1 J102

32 2 LS1,MK1

33 DC-JACK 2.0mm 1 J101

34 1 S101

35 1 X30136 10 2 J301,J302

-SIM300 PCBABOM


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sim300 an deskphone design v1.02

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