REV. 0

AD7741/AD7742

–5–

AD7741 PIN FUNCTION DESCRIPTION

Pin No.

Mnemonic

Function

Power Supply Input. These parts can be operated from +4.75 V to +5.25 V and the supply should

be adequately decoupled to GND.

2

GND

Ground reference point for all circuitry on the part.

3

CLKOUT

External Clock Output. When the master clock for the device is a crystal, the crystal is connected

between CLKIN and CLKOUT. When an external clock is applied to CLKIN, the CLKOUT pin

provides an inverted clock signal. This clock should be buffered if it is to be used as a clock source

elsewhere in the system.

4

CLKIN

External Clock Input. The master clock for the device can be provided in the form of a crystal or an

external clock. A crystal may be tied across the CLKIN and CLKOUT pins. Alternatively, the

CLKIN pin may be driven by a CMOS-compatible clock and CLKOUT left unconnected. The

frequency of the master clock may be as high as 6 MHz.

5

REFIN/OUT

This is the reference input to the core of the VFC and defines the span of the VFC. If this pin is left

unconnected, the internal 2.5 V reference is used. Alternatively, a precision external reference (e.g.,

REF192) may be used to overdrive the internal reference. The internal bandgap reference has a

high output impedance in order to allow it to be overdriven.

draws virtually no current from whatever source is driving it.

7

PD

Active Low Power-Down pin. When this input is low, the part enters power-down mode where it

typically consumes 15

µA of current.

Frequency Output. This pin provides the output of the synchronous VFC.

PIN CONFIGURATION

TOP VIEW

(Not to Scale)

8

7

6

5

1

2

3

4

AD7741

GND

PD

CLKOUT

CLKIN

REFIN/OUT