REV. C

ADF4217L/ADF4218L/ADF4219L

–6–

PIN FUNCTION DESCRIPTIONS

Mnemonic

Function

Output from the RF Charge Pump. When enabled, this provides

±I

drives the external VCO.

Ground Pin for the RF Digital Circuitry

Input to the RF Prescaler. This low level input signal is normally ac-coupled to the external VCO.

bypass capacitor, typically 100 pF.

Ground Pin for the RF Analog Circuitry

100 k

Ω. This input can be driven from a TTL or CMOS crystal oscillator, or can be ac-coupled.

Ground Pin for the IF Digital, Interface, and Control Circuitry

MUXOUT

This multiplexer output allows either the IF/RF Lock Detect, the scaled RF, or the scaled Reference Frequency to

be accessed externally (Table V).

CLK

Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into the

22-bit shift register on the CLK rising edge. This input is a high impedance CMOS input.

DATA

Serial Data Input. The serial data is loaded MSB first with the two LSBs being the control bits. This input is a

high impedance CMOS input.

LE

Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the four

latches; the latch is selected using the control bits.

Ground Pin for the IF Analog Circuitry

NC

This pin is not connected internally (ADF4219L only).

capacitor, typically 100 pF (ADF4217L/ADF4218L only).

Input to the IF Prescaler. This low level input signal is normally ac-coupled to the external VCO.

Ground Pin for the IF Digital, Interface, and Control Circuitry

Output from the IF Charge Pump. When enabled, this provides

±I

the external VCO.