NJM2211

The NJM2211 has the following features including Wide Operating Voltage(4.5V to 20V);Wide frequency range(0.01 Hz to 300 kHz);DTL/TTL/ECL logic compatibility;FSK demodulation with catTier-detector;Wide dynamic range(2mV to 3Vrms);Bipolar Technology.

The NJM2211 is a  monolithic phase-locked loop (PLL) system especially designed for data communications. NJM2211 is particularly well suited for FSK modem applications, and operates over a wide frequency range of O.O1Hz to 300kHz. It can accommodate analog signals between 2mV and 3V, and can interface with conventional DTL, TTL and ECL logic families. The circuit consists of a basic PLL for tracking an input signal frequency within the passband, a quadrature phase detector which provides carrier detection, and an FSK voltage comparator which provides FSK demodulation. External components are used to independently set carrier frequency, bandwidth, and output delay.This is the high-impedance output of the quadrature phase detector, and is internally connected to the input of lock-detect voltage comparator. In tone detection applications, pin 3 is connected to ground through a parallel combination of RD and CD (see Figure 1) to eliminate chatter at the flock-detect outputs. If this tone-detect section is not used, pin 3 can be left open circuited.

This output is an open collector logic stage which rcdurcs a pull-up resistor, R,,to V+ for proper operation. NJM2211 can sink SmA of load current. When decoding FSK signals the FSK data output will switch to a "high" or off state for low input frequency, and will switch to a "low" or on state for high input frequency. If no input signal is present, the logic state at pin 7 is indeterminate.The NJM2211 does not have a separate Vco output terminal. Instead, the VCO outputs ae internally connected to the phase-detector sections of the circuit. However, for setup or adjustment purposes, the VCO free-running frequency can be measured at pin 3 (with Cd disconnected) with no input and also pin 2 shorted to pin I0.