74HCT7046A Datasheet | Philips Semiconductors

FEATURES - Low power consumption - Centre frequency up to 17 MHz (typ.) at VCC = 4.5 V - Choice of two phase parators: EXCLUSIVE-OR; edge-triggered JK flip-flop; - Excellent VCO frequency linearity - VCO-inhibit control for ON/OFF keying and for low standby power consumption - Minimal frequency drift - Operation power supply voltage range: VCO section 3.0 to 6.0 V digital section 2.0 to 6.0 V - Zero voltage offset due to op-amp buffering - Output capability: standard - ICC category: MSI GENERAL DESCRIPTION The 74HC/HCT7046 are high-speed Si-gate CMOS devices and are specified in pliance with JEDEC standard no. 7. The 74HC/HCT7046 are phase-locked-loop circuits that prise a linear voltage-controlled oscillator (VCO) and two different phase parators (PC1 and PC2) with a mon signal input amplifier and a mon parator input. A lock detector is provided and this 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). The value of the CLD capacitor can be determined, using information supplied in Fig.32. The input signal 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 December 1990 amplifiers. With a passive low-pass filter, the “7046” forms a second-order loop PLL. The excellent VCO linearity is achieved by the use of linear op-amp techniques. VCO The VCO requires one external capacitor C1 (between C1A and C1B) and one external resistor R1 (between R1 and GND) or two external resistors R1 and R2 (between R1 and GND, and R2 and GND). Resistor R1 and capacitor C1 determine the frequency range of the VCO. Resistor R2 enables the VCO to have a frequency offset if required. The high input impedance of the VCO simplifies the design of low-pass filters by giving the designer a wide choice of resistor/capacitor ranges. In order not...