The 74HC/HCT4046A are high-speed Si-gate CMOS devices and are pin compatible with the “4046” of the “4000B” series. They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT4046A are phase-locked-loop circuits that comprise a linear voltage-controlled oscillator (VCO) and three different phase comparators (PC1, PC2 and PC3) with a common signal input amplifier and a common comparator input. The signal input can be directly coupled to large voltage signals, or indirectly coupled (with a series capacitor) to small voltage signals. A self-bias input circuit keeps small voltage signals within the linear region of the input amplifiers. With a passive low-pass filter, the “4046A” forms a second-order loop PLL. The excellent VCO linearity is achieved by the use of linear op-amp techniques.
Low power consumption
Centre frequency of up to 17 MHz (typ.) at VCC = 4.5 V
Choice of three phase comparators: EXCLUSIVE-OR; edge-triggered JK flip-flop; edge-triggered RS flip-flop
Excellent VCO frequency linearity
VCO-inhibit control for ON/OFF keying and for low standby power consumption