Altec GSM SOCKET AL7020S - Manual (Page 12)

AL7020S, AL7024S Designer’s Guide
Doc. No. DG_7024E Altec Electronic AG Seite 12 / 32
Table 3-3. Signal Descriptions (Cont'd)
Label
I/O Type
Signal Name/Description
LED driver lines are open-drain inverter-driven (74HCT05) lines with 1.5 KΩ, 1/10W pull-up resistors.
GSM LED OG
GSM activity LED. active low !
connect LED to 5V with resistor in series.
GPRS LED OG
GPRS activity LED. active low !
connect LED to 5V with resistor in series.
Audio/Headset Interface
MICV I(DA)
Microphone Voice Input. MICV is a single-ended microphone
input from the analog switch circuit. The maximum input to the
MICV pin before there is signal distortion in the network is
12mVRMS.
SPKR O(DF) Speaker Output. SPKR is a single-ended output.
AGND PWR Analog Ground. Analog Ground related to MICV Input.
Notes:
1. I/O types:
I(DA) = Analog input (see Table 3-5).
O(DD),O(DF) = Analog output (see Table 3-5).
IO(DX) = Analog input/output (see Table 3-5).
Table 3-4. Analog Electrical Characteristics
Name Type
Characteristic
Value
SPKR O(DF)
Recommended characteristics for
the speaker:
Impedance: 32 Ω (handset)
Power: 10mW
Sound Pressure.: 110dB
MICV I(DA)
Recommended characteristics for
the microphone:
Bias Voltage: 2.2V ( 0.5mA )
Impedance: 2 KOhms
Sensitivity: –40 to –50dB
SNR: > 50dB