IN74HC4046A
PHASE-LOCKED LOOP
High-Performance Silicon-Gate CMOS
The device inputs are compatible with standard CMOS outputs; with
pullup resistors, they are compatible with LS/ALSTTL outputs.
The IN74HC4046A phase-locked loop contains three phase
comparators, a voltage-controlled oscillator (VCO) and unity gain op-
amp DEMOUT. The comparators have two common signal inputs,
COMPIN, and SIGIN. Input SIGIN and COMPIN can be used directly
coupled to large voltage signals, or indirectly coupled (with a series
capacitor to small voltage signals). The self-bias circuit adjusts small
voltage signals in the linear region of the amplifier. Phase comparator 1
(an exclusive OR gate) provides a digital error signal PC1OUT and
maintains 90 degrees phase shift at the center frequency between
ORDERING INFORMATION
SIGIN and COMPIN signals (both at 50% duty cycle). Phase comparator
2 (with leading-edge sensing logic) provides digital error signals
PC2OUT and PCPOUT and maintains a 0 degree phase shift between
SIGIN and COMPIN signals (duty cycle is immaterial). The linear VCO
produces an output signal VCOOUT whose frequency is determined by
the voltage of input VCOIN signal and the capacitor and resistors
connected to pins C1A, C1B, R1 and R2. The unity gain op-amp
output DEMOUT with an external resistor is used where the VCOIN
signal is needed but no loading can be tolerated. The inhibit
input, when high, disables the VCO and all on-amps to minimize
standby power consumption.
IN74HC4046AN Plastic
IN74HC4046AD SOIC
TA = -55° to 125° C for all
packages
PIN ASSIGNMENT
Applications include FM and FSK modulation and
demodulation, frequency synthesis and multiplication, frequency
discrimination, tone decoding, data synchronization and
conditioning, voltage-to-frequency conversion and motor speed
control.
• Low Power Consumption Characteristic of CMOS Device
• Operating Speeds Similary to LS/ALSTTL
• Wide Operating Voltage Range: 3.0 to 6.0 V
• Low Input Current: 1.0 µA Maximum (except SIGIN and COMPIN)
• Low Quiescent Current: 80 µA Maximum (VCO disabled)
• High Noise Immunity Characteristic of CMOS Devices
• Diode Protection on all Inputs
Pin No.
Symbol
PCPOUT
PC1OUT
COMPIN
VCOOUT
INH
Name and Function
Phase Comparator Pulse Output
Phase Comparator 1 Output
Comparator Input
1
2
3
4
VCO Output
5
Inhibit Input
6
C1A
Capacitor C1 Connection A
Capacitor C1 Connection B
Ground (0 V) VSS
7
C1B
8
GND
9
VCOIN
DEMOUT
R1
VCO Input
10
11
12
13
14
15
16
Demodulator Output
Resistor R1 Connection
Resistor R2 Connection
Phase Comparator 2 Output
Signal Input
R2
PC2OUT
SIGIN
PC3OUT
VCC
Phase Comparator 3 Output
Positive Supply Voltage
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