Differential/Single-Ended Input, Dual

1 MSPS, 12-Bit, 3-Channel SAR ADC

AD7265

Rev. A

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FEATURES

FUNCTIONAL BLOCK DIAGRAM

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

OUTPUT

DRIVERS

CONTROL

LOGIC

T/H

BUF

MUX

REF

AD7265

REF SELECT

BUF

OUTPUT

DRIVERS

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

T/H

MUX

DGND

DGND

CS

SCLK

RANGE

SGL/DIFF

A0

A1

A2

Dual 12-bit, 3-channel ADC

Throughput rate: 1 MSPS

Power consumption

7 mW at 1 MSPS with 3 V supplies

17 mW at 1 MSPS with 5 V supplies

Pin-configurable analog inputs

12-channel single-ended inputs

6-channel fully differential inputs

6-channel pseudo differential inputs

70 dB SINAD at 50 kHz input frequency

Accurate on-chip reference: 2.5 V

±0.2% maximum @ 25°C, 20 ppm/°C maximum

Dual conversion with read 875 ns, 16 MHz SCLK

High speed serial interface

SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible

−40°C to +125°C operation

Shutdown mode: 1 μA maximum

32-lead LFCSP and 32-lead TQFP

2 MSPS version, AD7266

GENERAL DESCRIPTION

Figure 1.

The AD72651 is a dual, 12-bit, high speed, low power, successive

approximation ADC that operates from a single 2.7 V to 5.25 V

power supply and features throughput rates of up to 1 MSPS. The

device contains two ADCs, each preceded by a 3-channel

multiplexer, and a low noise, wide bandwidth track-and-hold

amplifier that can handle input frequencies in excess of 30 MHz.

PRODUCT HIGHLIGHTS

1. Two Complete ADC Functions Allow Simultaneous

Sampling and Conversion of Two Channels.

Each ADC has three fully/pseudo differential pairs, or six

single-ended channels, as programmed. The conversion

result of both channels is simultaneously available on

separate data lines, or in succession on one data line if only

one serial port is available.

The conversion process and data acquisition use standard

control inputs allowing easy interfacing to microprocessors or

DSPs. The input signal is sampled on the falling edge of CS;

conversion is also initiated at this point. The conversion time is

determined by the SCLK frequency. The AD7265 uses advanced

design techniques to achieve very low power dissipation at high

throughput rates. With 5 V supplies and a 1 MSPS throughput rate,

the part consumes 4 mA maximum. The part also offers flexible

power/throughput rate management when operating in normal

mode, because the quiescent current consumption is so low.

2. High Throughput with Low Power Consumption.

The AD7265 offers a 1 MSPS throughput rate with 9 mW

maximum power dissipation when operating at 3 V.

and a 2 × V

input range.

REF

4. No Pipeline Delay.

The part features two standard successive approximation

ADCs with accurate control of the sampling instant via a

The analog input range for the part can be selected to be a 0 V

to V

CS

input and once off conversion control.

(or 2 × V

REF

REF

) range, with either straight binary or twos

complement output coding. The AD7265 has an on-chip 2.5 V

reference that can be overdriven when an external reference is

preferred. This external reference range is 100 mV to V

DD

. The

AD7265 is available in 32-lead LFCSP and 32-lead TQFP.