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
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
transitiononHFIpin.WhenHFOishigh,thehand-freefunctionisenabledand PO
outputs a high to connect the line.
Thehand-freefunctioncanbereleasedbysettingHDOhighorbyanon-off-hookop-
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
Positive power supply, 2.0V~5.5V for normal operation
VSS
Negative power supply, ground
Approximate internal connection circuits
Absolute Maximum Ratings
Supply Voltage ........................................... 0.3V to 6V
Input Voltage .............................. V
SS
0.3 to V
DD
+0.3V
Storage Temperature ........................... 50 C to 125 C
Operating Temperature .......................... 20 C to 75 C
Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maximum 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 reliabil-
ity.
HT9315 Series
Rev. 1.20
4
October 1, 2002
7
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4
7 $
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7
8
7
8
9 '
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4