Absolute Maximum Ratings*
Supply Voltage.................................–0.3V to 6V
Storage Temperature.................–50
°
C to 125
°
C
Operating Temperature...............–20
°
C to 70
°
C
Input Voltage................. V
SS
–0.3V to V
DD
+0.3V
*Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute Maxi-
mum Ratings” may cause substantial damage to the device. Functional operation of this
device at other conditions beyond those listed in the specification is not implied and prolonged
exposure to extreme conditions may affect device reliability.
Electrical Characteristics
(Ta=25
°
C)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
DD
Conditions
V
DD
Operating Voltage
—
—
4.5
—
5.5
V
I
DD
Operating Current
5V
No load,
f
OSC
=640kHz
—
1.5
3.0
mA
I
STB
Standby Current
5V
—
—
600
800
μ
A
I
O
Max. AUD Source Current
5V
V
OH
=0.6V
–1.5
–3.0
—
mA
I
OL
MOTOR Source Current
5V
V
OH
=4.5V
–1
–3.5
—
mA
I
OL
LE D Sink Current
5V
V
OL
=0.5V
3.0
5.0
—
mA
V
IH
“H” Input Voltage
—
—
0.7V
DD
—
V
DD
V
V
IL
“L” Input Voltage
—
—
0
—
0.3V
DD
V
V
OUT
Max. VOUT Output Voltage
5V
R
L
>50k
—
1.5
—
V
P-P
f
OSC
Oscillating Frequency
5V
R
OSC
=43k
—
640
—
kHz
Functional Description
The HT8656 is a single chip LSI with an exter-
nal DRAM. It is designed for talking back appli-
cations. The recording length of the IC is
determined by the data rate along with the size
of an external memory. Sounds coming from an
external microphone are coded through an in-
ternal ADM algorithm and saved in an external
memory until the memory is full or an interval
of silence lasts over 0.5 seconds. Once recording
is terminated, the IC will play back the recorded
sounds automatically.
Record function
The HT8656 provides two kinds of sampling
rate and DRAM size selection to determine the
recording capacity. The recording capacity is
determined as shown on the following table.
HT8656
5
5th May ’98