© 2002 Fairchild Semiconductor Corporation DS005968 www.fairchildsemi.com
October 1987
Revised March 2002
CD4046BC Micropower Phase-Locked Loop
CD4046BC
Micropower Phase-Locked Loop
General Description
The CD4046BC micropower phase-locked loop (PLL) con-
sists of a low power, linear, voltage-controlled oscillator
(VCO), a source follower, a zener diode, and two phase
comparators. The two phase comparators have a common
signal input and a common comparator input. The signal
input can be directly coupled for a large voltage signal, or
capacitively coupled to the self-biasing amplifier at the sig-
nal input for a small voltage signal.
Phase comparator I, an exclusive OR gate, provides a digi-
tal error signal (phase comp. I Out) and maintains 90
°
phase shifts at the VCO center frequency. Between signal
input and comparator input (both at 50% duty cycle), it may
lock onto the signal input frequencies that are close to har-
monics of the VCO center frequency.
Phase comparator II is an edge-controlled digital memory
network. It provides a digital error signal (phase comp. II
Out) and lock-in signal (phase pulses) to indicate a locked
condition and maintains a 0
° phase shift between signal
input and comparator input.
The linear voltage-controlled oscillator (VCO) produces an
output signal (VCO Out) whose frequency is determined by
the voltage at the VCO
IN
input, and the capacitor and resis-
tors connected to pin C1
A
, C1
B
, R1 and R2.
The source follower output of the VCO
IN
(demodulator Out)
is used with an external resistor of 10 k
Ω or more.
The INHIBIT input, when high, disables the VCO and
source follower to minimize standby power consumption.
The zener diode is provided for power supply regulation, if
necessary.
Features
■ Wide supply voltage range: 3.0V to 18V
■ Low dynamic power consumption: 70
µW (typ.)
at f
o
= 10 kHz, V
DD
= 5V
■ VCO frequency: 1.3 MHz (typ.) at V
DD
= 10V
■ Low frequency drift: 0.06%/
°C at V
DD
= 10V with
temperature
■ High VCO linearity: 1% (typ.)
Applications
• FM demodulator and modulator
• Frequency synthesis and multiplication
• Frequency discrimination
• Data synchronization and conditioning
• Voltage-to-frequency conversion
• Tone decoding
• FSK modulation
• Motor speed control
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Order Number Package Number Package Description
CD4046BCM M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
CD4046BCN N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
