ISD1700A SERIES
PIN NAME
V
SSP1
PDIP
PIN NO.
16
FUNCTIONS
Ground for Positive PWM Speaker Driver:
It is important to have a
separate path for each ground signal including V
SSA
, V
SSD
, V
SSP1
and V
SSP2
to minimize the noise coupling.
Auxiliary Output:
AUD is a single-ended current output. It can be used to
drive an external amplifier.
Automatic Gain Control (AGC):
The AGC adjusts the gain of the
preamplifier dynamically to compensate for the wide range of microphone
input levels. The AGC allows the full range of signals to be recorded with
minimal distortion. The AGC is designed to operate with a nominal
capacitor of 4.7 µF connected to this pin.
Connecting this pin to ground (V
SSA
) provides maximum gain to the
preamplifier circuitry. Conversely, connecting this pin to the power supply
(V
CCA
) provides minimum gain to the preamplifier circuitry.
Volume Control:
This control has 8 steps of volume adjustment. Each
Low pulse decreases the volume by one level. Repeated pulses decrease
the volume level from the current setting to the minimum then increase
back to the maximum, and continue this loop. The factory default is set at
maximum. This pin has an internal pull-up device
[1]
and an internal
debounce (T
Deb
)
[2]
for start and end, allowing the use of a push button
switch.
Oscillator Resistor:
A resistor connected from R
OSC
pin to ground
determines the sample frequency of the device, which sets the duration.
Please refer to the Duration Section for details.
Analog Power Supply.
It is important to have a separate path for each
power signal including V
CCD
, V
CCA
and V
CCP
to minimize the noise
coupling. Decoupling capacitors to V
SSA
should be as close to the device
as possible.
Feed-through:
When FT is engaged Low, the AnaIn feed-through path is
activated. As a result, the AnaIn signal is transmitted directly from AnaIn
to both the Speaker and AUD outputs, via the volume control circuit. This
pin has an internal pull-up device
[1]
and an internal debounce (T
Deb
)
[2]
for
start and end, allowing the use of a push button switch.
Playback:
Pulsing
PLAY
to Low once initiates a playback operation.
Playback stops automatically when it reaches the end of the message.
Pulsing it to Low again during playback stops the operation.
Holding
PLAY
Low constantly functions as a sequential playback
operation loop. This looping continues until
PLAY
returns to High. This
pin has an internal pull-up device
[1]
and an internal debounce (T
Deb
)
[2]
for
start and end, allowing the use of a push button switch.
AUD
AGC
17
18
VOL
19
R
OSC
20
V
CCA
21
FT
22
PLAY
23
Confidential
-9-
Publication Release Date: March 28, 2005
Revision A0
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