ADC12040 datasheet(3/20 Pages) NSC

3 / 20 page

Pin Descriptions and Equivalent Circuits

Pin No.

Symbol

Equivalent Circuit

Description

ANALOG I/O

IN+

Non-Inverting analog signal Input. With a 2.0V reference

voltage, the differential input signal level is 2.0 V

P-P centered

on V

CM.

IN−

Inverting analog signal Input. With a 2.0V reference voltage

the input signal level is 2.0 V

P-P centered on VCM. This pin

may be connected to V

CM for single-ended operation, but a

differential input signal is required for best performance.

REF

Reference input. This pin should be bypassed to AGND with

a 0.1 µF monolithic capacitor. V

REF is 2.0V nominal and

should be between 1.0V to 2.2V.

These pins are high impedance reference bypass pins only.

Connect a 0.1 µF capacitor from each of these pins to AGND.

DO NOT connect anything else to these pins.

DIGITAL I/O

CLK

Digital clock input. The range of frequencies for this input is

100 kHz to 50 MHz (typical) with guaranteed performance at

40 MHz. The input is sampled on the rising edge of this input.

OE is the output enable pin that, when low, enables the

TRI-STATE™ data output pins. When this pin is high, the

outputs are in a high impedance state.

8PD

PD is the Power Down input pin. When high, this input puts

the converter into the power down mode. When this pin is

low, the converter is in the active mode.

ADC12040 Datasheet(PDF) 3 Page - National Semiconductor (TI)