CD74HC7046AE

The CD74HC7046A and CD74HCT7046A high-speed silicon-gate CMOS devices, specified in compliance with JEDEC Standard No. 7A, are phase-locked-loop (PLL) circuits that contain a linear voltage-controlled oscillator (VCO), two-phase comparators (PC1, PC2), and a lock detector. A signal input and a comparator input are common to each comparator. The lock detector gives a HIGH level at pin 1 (LD) when the PLL is locked. The lock detector capacitor must be connected between pin 15 (CLD) and pin 8 (Gnd). For a frequency range of 100kHz to 10MHz, the lock detector capacitor should be 1000pF to 10pF, respectively.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 7046A forms a second-order loop PLL. The excellent VCO linearity is achieved by the use of linear op-amp techniques.