Pin Name

I/O

Internal

Connection

Description

HFI

I

CMOS IN

Pull-Low

This pin is a Schmitt trigger input structure. Active high. Applying a positive pulse

to HFI can toggle the HFO once and hence control the hand-free function. The

pull-low resistance of HFI is 200k

W typ.

An external RC network is recommended for input debouncing.

HFO

O

CMOS OUT

The HFO is a CMOS output structure. Its output is toggle- controlled by a positive

transition on HFI pin. When HFO is high, the hand-free function is enabled and PO

outputs a high to connect the line.

The hand-free function can be released by setting HDO high or by an on-off-hook op-

eration or by another HFI input. Refer to the functional description for the hand-free

functional operation.

DOUT

O

NMOS OUT

NMOS open drain output pin. It outputs the BCD code of the dialing digits to the

LCD driver chip (HT16XX series) or MCU for dialing number display. Refer to the

functional description for the detailed timing.

CLOCK

O

NMOS OUT

NMOS open drain output. When dialing, it outputs a series of pulse trains for

DOUT data synchronization. DOUT data is valid at the falling edge of the clock.

VDD

¾¾

Positive power supply, 2.0V~5.5V for normal operation

VSS

¾¾

Negative power supply, ground

Approximate internal connection circuits

Absolute Maximum Ratings

Supply Voltage ...........................................

-0.3V to 6V

Storage Temperature ...........................

-50°Cto125°C

Operating Temperature ..........................

-20°Cto75°C

Note: These are stress ratings only. Stresses exceeding the range specified under

²Absolute Maximum Ratings² 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 reliabil-

ity.

HT9315 Series

Rev. 1.20

4

October 1, 2002

N M O S O U T

V D D

C M O S I N / O U T

C M O S I N

P u l l - L o w

C M O S I N

P u l l - H i g h

C M O S I N

O S C I L L A T O R

X 1

X 2

E N

1 0 M

2 0 P

1 0 P

C M O S O U T

V D D