hardware design v2.00
Table Of Contents
- Contents
- Version History
- 1 Introduction
- 2 SIM908 Overview
- 3 Package Information
- 4 GSM Application Interface
- 4.1 Power Supply
- 4.2 Power on/down Scenarios
- 4.3 Power Saving Mode
- 4.4 Charging Interface
- 4.5 RTC Backup
- 4.6 Serial Interfaces
- 4.7 Audio Interfaces
- 4.8 SIM Card Interface
- 4.9 LCD Display/SPI Interface
- 4.10 Keypad Interface
- 4.11 ADC
- 4.12 RI Behaviors
- 4.13 Network Status Indication
- 4.14 General Purpose Input/Output (GPIO)
- 4.15 PWM
- 4.16 I2C Bus
- 4.17 GSM Antenna Interface
- 5 GPS Application Interface
- 6 Electrical, Reliability and Radio Characteristics
- 6.1 Absolute Maximum Ratings
- 6.2 Recommended Operating Conditions
- 6.3 Digital Interface Characteristics
- 6.4 SIM Card Interface Characteristics
- 6.5 VDD_EXT Characteristics
- 6.6 SIM_VDD Characteristics
- 6.7 VRTC Characteristics
- 6.8 Current Consumption (VBAT = 3.8V, GPS engine is powered down)
- 6.9 Electro-Static Discharge
- 6.10 Radio Characteristics
- 6.11 Module label information
- Appendix
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SIM908_Hardware Design_V2.00 2012.05.07
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6.9 Electro-Static Discharge
SIM908 is an ESD sensitive component, so more attention should be paid to the procedure of handling and
packaging. The ESD test results are shown in the following table.
Table
28: The ESD characteristics (Temperature: 25℃, Humidity: 45 %)
Pin Contact discharge Air discharge
VBAT ±5KV ±10KV
GND ±4KV ±10KV
RXD, TXD ±3KV ±6KV
Antenna port ±5KV ±10KV
SPKP/ SPKN
MICP/ MICN
±3KV ±8KV
PWRKEY ±3KV ±8KV
Note: It is suggested that customers in serials with 100ohm resistances on UART lines for ESD consideration.
6.10 Radio Characteristics
6.10.1 Module RF Output Power
The following table shows the module conducted output power, it is followed by the 3GPP TS 05.05 technical
specification requirement.
Table 29: SIM908 GSM 900 and GSM 850 conducted RF output power
GSM 900 and EGSM 850
Tolerance (dB) for conditions
PCL Nominal output power (dBm)
Normal Extreme
0-2 39 ±2 ±2.5
3 37 ±3 ±4
4 35 ±3 ±4
5 33 ±3 ±4
6 31 ±3 ±4
7 29 ±3 ±4
8 27 ±3 ±4
9 25 ±3 ±4
10 23 ±3 ±4
11 21 ±3 ±4
12 19 ±3 ±4
13 17 ±3 ±4