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LC72134M
Continued from preceding page.
Pin
Pin No.
Type
Function
Equivalent circuit
Main PLL
local oscillator
signal input
AMIN is selected when DVS in the serial data is set to 0.
When SNS in the serial data is set to 1:
Input frequency: 2 to 40 MHz
The signal is input to the swallow counter directly.
The divisor can be set to a value in the range 272 to 65535. The set value
becomes the actual divisor.
When SNS in the serial data is set to 0:
Input frequency: 0.5 to 10 MHz
The signal is input to a 12-bit programmable divider directly.
The divisor can be set to a value in the range 5 to 4095. The set value becomes
the actual divisor.
AMIN
17
Chip enable
This pin must be set high to enable serial data input (DI) or serial data output
(DO).
CE
2
Input data
Input for serial data transferred from the controller
DI
3
Clock
Clock used for data synchronization for serial data input (DI) and serial data
output (DO).
CL
4
Output data
Output for serial data transmitted to the controller. The content of the data
transmitted is determined by DOC0 through DOC2.
DO
5
Power supply
LC72134M power supply (VDD = 4.5 to 5.5 V)
The power on reset circuit operates when power is first applied.
——
VDD
19
Ground
LC72134M ground
——
VSS
23
Output ports
Output-only ports
The output state is determined by BO1 through BO4 in the serial data.
When the data value is 0: The output state will be the open circuit state.
When the data value is 1: The output state will be a low level.
A time base signal (8 Hz) is output from BO1 when TBC in the serial data is set to
1.
BO1
BO2
BO3
BO4
6
7
8
14
I/O port
Shared function I/O port
The pin function is determined by IOC2 in the serial data.
When the data value = 0: Input port
When the data value = 1: Output port
When specified to function as an input port:
The input pin state is reported to the controller through the DO pin.
When the input state is low: The data will be 0:
When the input state is high: The data will be 1:
When specified to function as an output port:
The output state is determined by IO2 in the serial data.
When the data value is 0: The output state will be the open circuit state.
When the data value is 1: The output state will be a low level.
This pin is set to input mode after a power on reset.
IO2
16
Main PLL
charge pump
output
PLL charge pump output
A high level is output when the frequency of the local oscillator signal divided by N
is higher than the reference frequency, and a low level is output when that
frequency is lower. This pin goes to the high-impedance state when the
frequencies match.
PDa
20
Main PLL low-
pass filter
amplifier
transistor
Connections for the n-channel MOS transistor to be used for the PLL active low-
pass filter.
AINa
AOUTa
21
22
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