I5216 Datasheet, PDF (48/83 Pages) Winbond – 8 TO 16 MINUTE VOICE RECORD/PLAYBACK SYSTEM WITH INTEGRATED CODEC

I5216 SERIES
Advanced Information
PRELIMINARY
ANALOG I/O PINS
MIC+, MIC- (Microphone Input +/-)
The microphone input transfers the voice signal to the on-chip AGC preamplifier or directly to the
CODEC A/D INPUT MUX, depending on the selected path. The AGC circuit has a range of 45 dB in
order to deliver a nominal 694 mV p-p into the storage array from a typical electric microphone output
of 2 to 20 mV p-p. The input impedance is typically 20 kΩ differential and 13.3 kΩ differential when the
CODEC INPUT MUX MICIN path is selected.
MICROPHONE INPUT
1.5kΩ
.1µF
MICBS
Electret Microphone
WM-54B Panasonic
MIC+
MIC -
.1µF
AGCCAP
1.5kΩ
4.7µF
2.2V Voltage
reference
Ra=10kΩ
(AGP¹D)
MIC IN
AGC
1
(AGPD)
CODEC INPUT MUX
( ) 2CDI0
CDI1
Rc=40kΩ
CODEC ADC IN
f
− 3dB
=
2⋅π
1
⋅ Ra ⋅ CCOUPLE
ACAP (AGC Capacitor)
This pin provides the capacitor connection for setting the parameters of the microphone AGC circuit. It
should have a 4.7 µF capacitor connected to ground. It cannot be left floating. This is because the
capacitor is also used in the playback mode for the AutoMute circuit or when signal compression is
chosen (AMT0 is set to ONE). This circuit reduces the amount of noise present in the output during
quiet pauses. Tying this pin to ground gives maximum gain. Tying it to V_CCA gives minimum gain for the
AGC amplifier, but cancels the AutoMute function.
Publication Release Date: November 30, 2001
- 48
Revision A1