ISD1000A Datasheet, PDF (5/20 Pages) List of Unclassifed Manufacturers – Single-Chip Voice Record/Playback Devices 16- and 20-Second Durations

Product Data Sheets
ISD1000A Series
Analog Output (ANA OUT)
This pin provides the preamplifier output to the
user. The voltage gain of the preamplifier is deter-
mined by the voltage level at the AGC pin. It has a
maximum gain of about 24 dB for small input sig-
nal levels.
Analog Input (ANA IN)
The analog input pin transfers its signal to the chip
for recording. For microphone inputs, the ANA
OUT pin should be connected via an external
capacitor to the ANA IN pin. This capacitor value,
together with the 2.7 KΩ input impedance of ANA
IN, is selected to give additional cutoff at the low-
frequency end of the voice passband. If the
desired input is derived from a source other than
a microphone, the signal can be fed, capacitively
coupled, into the ANA IN pin directly.
Optional External Clock Input (XCLK)
ISD1000A devices are configured at the factory
with an internal sampling clock frequency cen-
tered to ± 1% of specification. The frequency is
maintained to a total variation of ± 2.25% toler-
ance over the entire commercial temperature and
4.5 to 5.5 voltage ranges. The internal clock has a
± 5% tolerance over the industrial temperature
range and 4.5 to 5.5 voltage range. A regulated
power supply is recommended for industrial-tem-
perature-range parts. If greater precision is
required, the device can be clocked through the
XCLK pin as follows.
Part
Number
ISD1016A
ISD1020A
Sample Rate Required Clock
8.0 KHz
6.4 KHz
1024 KHz
819.2 KHz
These recommended clock rates should not be
varied because the antialiasing and smoothing fil-
ters are fixed, and aliasing problems can occur if
the sample rate differs from the one recom-
mended. The duty cycle on the input clock is not
critical, as the clock is immediately divided by
two. IF THE XCLK IS NOT USED, THIS INPUT MUST BE
CONNECTED TO GROUND.
Speaker Outputs (SP+/SP-)
All devices in the ISD1000A Series include an on-
chip differential speaker driver, capable of driving
50 milliwatts into 16 Ω from AUX IN (12.2 mW from
memory).
The speaker outputs are held at V_SSA levels during
record and power down. It is therefore not possi-
ble to parallel speaker outputs of multiple
ISD1000A devices or the outputs of other speaker
drivers.
NOTE
Connection of speaker outputs in parallel
may cause damage to the device.
1
While a single output may be used alone (includ-
ing a coupling capacitor between the SP pin and
the speaker), these outputs may be used individ-
ually with the output signal taken from either pin.
Using the differential outputs results in a 4:1
improvement in output power.
NOTE
Never ground or drive an output.
Auxiliary Input (AUX IN)
The Auxiliary Input is multiplexed through to the
output amplifier and speaker output pins when CE
is HIGH and Playback has ended, or if the device
is in overflow. When cascading multiple ISD1000A
devices, the AUX IN pin is used to connect a Play-
back signal from a following device to the
previous output speaker drivers. For noise consid-
erations, it is suggested that the Auxiliary Input not
be driven when the storage array is active.
Address/Mode Inputs (Ax/Mx)
The Address/Mode Inputs provide two functions in
the ISD1000A Series: 1. Message address (either
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