Continued from preceding page.
Symbol
VSS
Pin No.
23
Type
Ground
LC72130, 72130M
Functions
• The LC72130 ground
Circuit configuration
—
BO1
BO2
BO3
BO4
BO5
• Dedicated output pins
• The output states are determined by BO1 to BO5 in the
7
serial data.
8
Data: 0 = open, 1 = low
9
Output port
• These pins go to the open state after the power on reset.
10
• An 8 Hz time base signal can be output from BO1 when
2
TBC in the serial data is set to 1.
• Note that the ON impedance of the BO1 pin is higher
than that of the other pins (BO2 to BO5).
• Pins used for both input and output
• The input or output state is determined by bits IOC1 and
IOC2 in the serial data.
Data: 0 = input port, 1 = output port
• When specified for use as an input port:
The input state is transmitted to the controller through
IO1
IO2
11
13
I/O port
the DO pin.
Input state: Low → data value = 0
High → data value = 1
• When specified for use as an output port:
The output state is determined by bits IO1 and IO2 in the
serial data.
Data: 0 = open, 1 = low
• These pins go to the input port state after the power ON
reset.
PD1
PD2
AIN1
AOUT1
AIN2
AOUT2
• PLL charge pump output
When the frequency generated by dividing the local
19
20
Charge pump
output
oscillator frequency by N is higher than the reference
frequency, a high level will be output from the PD pin.
Similarly, when that frequency is lower, a low level will
be output. The PD pin goes to the high impedance state
when the frequencies agree.
18
17
21
22
LPF amplifier
transistor
• The MOS transistor used for the PLL active low-pass
filter.
• The input frequency range is from 0.4 to 12 MHz.
• The signal is supplied directly to the IF counter.
IFIN
12
IF counter
• The result from the IF counter MSB is output through the
DO pin.
• There are four measurement periods: 4, 8, 32, or 64 ms.
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