Absolute Maximum Ratings*

Supply Voltage ................................. –0.3V to 6V

Storage Temperature................. –50

Operating Temperature............... –20

*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

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Conditions

Operating Voltage

—

—

4.5

—

5.5

V

Operating Current

5V

No load,

—1.5

3.0

mA

Standby Current

5V

—

—

600

800

Max. AUD Source Current

5V

–1.5

–3.0

—

mA

MOTOR Source Current

5V

–1

–3.5

—

mA

LED Sink Current

5V

3.0

5.0

—

mA

“H” Input Voltage

—

—

V

“L” Input Voltage

—

—

0

—

V

Max. VOUT Output Voltage

5V

Ω

—1.5

—

Oscillating Frequency

5V

Ω

—

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