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AD7482

3 MSPS, 12-Bit SAR ADC

FEATURES

Fast Throughput Rate: 3 MSPS

Wide Input Bandwidth: 40 MHz

No Pipeline Delays with SAR ADC

Excellent DC Accuracy Performance

Two Parallel Interface Modes

Low Power:

90 mW (Full Power) and 2.5 mW (NAP Mode)

Standby Mode: 2

A Max

Single 5 V Supply Operation

Internal 2.5 V Reference

Full-Scale Overrange Mode (using 13th Bit)

System Offset Removal via User Access Offset Register

Nominal 0 V to 2.5 V Input with Shifted Range

Capability

14-Bit Pin Compatible Upgrade AD7484 Available

FUNCTIONAL BLOCK DIAGRAM

2.5 V

REFERENCE

NAP

MODE2

BUF

T/H

DGND

REFSEL

REFOUT

REFIN

VIN

12-BIT

ALGORITHMIC SAR

MODE1

CLIP

STBY

RESET

CONVST

D12

CONTROL

LOGIC AND I/O

REGISTERS

AD7482

D11

D10

D9

D8

D7

D6

D5

GENERAL DESCRIPTION

The AD7482 is a 12-bit, high speed, low power, successive-

approximation ADC. The part features a parallel interface with

throughput rates up to 3 MSPS. The part contains a low noise,

wide bandwidth track-and-hold that can handle input fre-

quencies in excess of 40 MHz.

The conversion process is a proprietary algorithmic successive-

approximation technique that results in no pipeline delays. The

input signal is sampled, and a conversion is initiated on the

falling edge of the

CONVST signal. The conversion process is

controlled via an internally trimmed oscillator. Interfacing is via

standard parallel signal lines, making the part directly compat-

ible with microcontrollers and DSPs.

The AD7482 provides excellent ac and dc performance specifi-

cations. Factory trimming ensures high dc accuracy resulting in

very low INL, offset, and gain errors.

The part uses advanced design techniques to achieve very low

power dissipation at high throughput rates. Power consumption

in the normal mode of operation is 90 mW. There are two power-

saving modes: a NAP Mode that keeps the reference circuitry alive

for a quick power-up while consuming 2.5 mW, and a STANDBY

Mode that reduces power consumption to a mere 10

µW.

The AD7482 features an on-board 2.5 V reference but can also

accommodate an externally provided 2.5 V reference source. The

nominal analog input range is 0 V to 2.5 V, but an offset shift

capability allows this nominal range to be offset by

±200 mV.

This allows the user considerable flexibility in setting the bottom

end reference point of the signal range, a useful feature when

using single-supply op amps.

The AD7482 also provides the user with an 8% overrange

capability via a 13th bit. Thus, if the analog input range strays

outside the nominal by up to 8%, the user can still accurately

resolve the signal by using the 13th bit.

The AD7482 is powered by a 4.75 V to 5.25 V supply. The part

is 2.7 V to 5.25 V. The part is housed in a 48-lead LQFP package

and is specified over a –40

°C to +85°C temperature range.