XR-2211A

5

Rev. 1.01

Parameter

Min.

Typ.

Max.

Unit

Conditions

Voltage Comparator Section

Input Impedance

2

M

W

Measured at pins 3 and 8

Input Bias Current

100

nA

Voltage Gain

55

70

dB

Output Voltage Low

300

500

mV

Output Leakage Current

0.01

10

mA

Internal Reference

Voltage Level

4.75

5.3

5.85

V

Measured at pin 10

Output Impedance

100

W

AC Small Signal

Maximum Source Current

80

mA

Note:

- These parameters, although guaranteed over the recommended operating conditions, are not 100% tested in production.

- Bold face parameters are covered by production test.

Specifications are subject to change without notice

ABSOLUTE MAXIMUM RATINGS

Power Supply

20V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input Signal Level

3V rms

. . . . . . . . . . . . . . . . . . . . . . . .

Power Dissipation

900mW

. . . . . . . . . . . . . . . . . . . . . . .

Plastic Package

800mW

. . . . . . . . . . . . . . . . . . . . . . . . .

6mW/

°C

. . . . . . . .

JEDEC SOIC

390mW

. . . . . . . . . . . . . . . . . . . . . . . . . .

5mW/

°C

. . . . . . . . .

SYSTEM DESCRIPTION

The main PLL within the XR-2211A is constructed from an

input preamplifier, analog multiplier used as a phase

detector and a precision voltage controlled oscillator

(VCO). The preamplifier is used as a limiter such that

input signals above typically 10mV RMS are amplified to a

constant high level signal. The multiplying-type phase

detector acts as a digital exclusive or gate. Its output

(unfiltered) produces sum and difference frequencies of

the input and the VCO output.

The VCO is actually a

current controlled oscillator with its normal input current

The output of the phase detector produces sum and

difference of the input and the VCO frequencies

(internally connected). When in lock, these frequencies

when lock). By adding a capacitor to the phase detector

DC voltage that represents the phase difference between

the two frequencies. This closes the loop and allows the

VCO to track the input frequency.

The FSK comparator is used to determine if the VCO is

driven above or below the center frequency (FSK

comparator).

This will produce both active high and

active low outputs to indicate when the main PLL is in lock

(quadrature

phase

detector

and

lock

detector

comparator).