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Differential/Single-Ended Input, Dual
1 MSPS, 12-Bit, 3-Channel SAR ADC
AD7265
Rev. A
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2006 Analog Devices, Inc. All rights reserved.
FEATURES
FUNCTIONAL BLOCK DIAGRAM
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
DOUTA
OUTPUT
DRIVERS
CONTROL
LOGIC
T/H
BUF
VA1
VA2
VA3
VA4
VA5
VA6
MUX
REF
AD7265
VDRIVE
REF SELECT
DCAPA
AVDD
DVDD
BUF
DOUTB
OUTPUT
DRIVERS
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
T/H
VB1
VB2
VB3
VB4
VB5
VB6
MUX
AGND AGND AGND DCAPB
DGND
CS
SCLK
RANGE
SGL/DIFF
A0
A1
A2
04674-001
Dual 12-bit, 3-channel ADC
Throughput rate: 1 MSPS
Specified for VDD of 2.7 V to 5.25 V
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
GENERAL DESCRIPTION
Figure 1.
The AD7265
1 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.
3. The AD7265 offers both a standard 0 V to VREF input range
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
) 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
1 Protected by U.S. Patent No. 6,681,332.
DD
. The
AD7265 is available in 32-lead LFCSP and 32-lead TQFP.