ISD2500 Datasheet, PDF (5/28 Pages) List of Unclassifed Manufacturers – Single-Chip Voice Record/Playback Devices 32-, 40-, 48-, 64-,60-,75,90-, and 120-Second Durations

Product Data Sheets
ISD2532/40/48/64* DEVICE PINOUTS
OVF ¹
CE
2
PD
3
EOM ⁴
XCLK ⁵
P/R ⁶
VCCD
7
NC
8
NC
9
A0/M0 ¹⁰
A1/M1 ¹¹
A2/M2 ¹²
A3/M3 ¹³
A4/M4 ¹⁴
A5/M5 ¹⁵
A6/M6 ¹⁶
ISD2532/40/48/64
TSOP
ISD2500 Series
32
ANA OUT
31
ANA IN
30
AGC
29
MIC REF
28
MIC
27
VCCA
26
SP–
25
NC
24
NC
23
SP+
22
VSSA
21
VSSD
20
AUX IN
19
A8
18
A7
17
NC
A0/M0
A1/M1
A2/M2
A3/M3
A4/M4
A5/M5
A6/M6
NC
A7
A8
AUX IN
VSSD
VSSA
SP+
1
28
2
27
3
26
4
25
5
24
6 _ISD2532 23
7 _ISD2540 22
8 _ISD2548 21
9 _ISD2564 20
10
19
11
18
12
17
13
16
14
15
DIP/SOIC
V_CCD
P/R
XCLK
EOM
PD
CE
OVF
ANA OUT
ANA IN
AGC
MIC REF
MIC
V_CCA
SP–
Microphone Input (MIC)
The microphone input transfers its signal to the on-
chip preamplifier. An on-chip Automatic Gain Con-
trol (AGC) circuit controls the gain of this
preamplifier from -15 to 24 dB. An external micro-
phone should be AC coupled to this pin via a series
capacitor. The capacitor value, together with the
internal 10 K ohm resistance on this pin, deter-
mines the low-frequency cutoff for the ISD2500
Series passband. See ISD's Application Notes and
Design Manual in this book for additional informa-
tion on low-frequency cutoff calculation.
Microphone Reference Input (MIC REF)
The MIC REF input is the inverting input to the
microphone preamplifier. This provides a noise-
canceling or common-mode rejection input to the
device when connected to a differential
microphone.
Automatic Gain Control Input (AGC)
The AGC dynamically adjusts the gain of the
preamplifier to compensate for the wide range of
microphone input levels. The AGC allows the full
range of whispers to loud sounds to be recorded
with minimal distortion. The “attack” time is deter-
mined by the time constant of a 5 KΩ internal
resistance and an external capacitor (C2 on the
schematic on page 1-100) connected from the
AGC pin to V_SSA analog ground. The “release”
time is determined by the time constant of an
1 ^{external resistor (R2) and an external capacitor}
(C2) connected in parallel between the AGC Pin
and V_SSA analog ground. Nominal values of
470 KΩ and 4.7 µF give satisfactory results in
most cases.
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.
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 3.0 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.
External Clock Input (XCLK)
The external clock input for the ISD2500 devices
has an internal pull-down device. These devices
are configured at the factory with an internal sam-
pling clock frequency centered to ±1% of
* ^{Advance information: ISD2532/40/48/64 devices.}
1–83