AD7656A-1_17 Datasheet, PDF (1/29 Pages) Analog Devices – 250 kSPS, 6-Channel, Simultaneous Sampling, Bipolar, 16-Bit ADC

Data Sheet
250 kSPS, 6-Channel, Simultaneous
Sampling, Bipolar, 16-Bit ADC
AD7656A-1
FEATURES
Pin and software compatible with the AD7656A featuring
reduced decoupling requirements
6 independent analog-to-digital converters (ADCs)
True bipolar analog inputs
Pin-/software-selectable ranges: ±10 V or ±5 V
Fast throughput rate: 250 kSPS
iCMOS process technology
Low power: 140 mW at 250 kSPS with 5 V supplies
High noise performance with wide bandwidth
88 dB SNR at 10 kHz input frequency
On-chip reference and reference buffers
High speed parallel, serial, and daisy-chain interface modes
High speed serial interface
Serial peripheral interface (SPI)/QSPI™/MICROWIRE®/DSP
compatible
Power-down mode: 315 µW maximum
64-lead LQFP
Built-in power supply sequencing (PSS) robustness solution
APPLICATIONS
Power line monitoring and measuring systems
Instrumentation and control systems
Multiaxis positioning systems
FUNCTIONAL BLOCK DIAGRAM
V_DD
CONVST A CONVST B CONVST C AV_CC DV_CC
REF
CLK
OSC
CONTROL
LOGIC
V1 T/H
BUF
16-BIT SAR
OUTPUT
DRIVERS
V2 T/H
V3 T/H
BUF
16-BIT SAR
16-BIT SAR
V4 T/H
V5 T/H
BUF
16-BIT SAR
16-BIT SAR
OUTPUT
DRIVERS
OUTPUT
DRIVERS
OUTPUT
DRIVERS
V6 T/H
V_SS
16-BIT SAR
AD7656A-1
AGND DGND
Figure 1.
CS
SER/PAR SEL
V_DRIVE
STBY
DB8/DOUT A
DB6/SCLK
DB9/DOUT B
DB10/DOUT C
DATA/
CONTROL
LINES
RD
WR/REF_EN/DIS
GENERAL DESCRIPTION
The AD7656A-1¹ is a reduced decoupling pin- and software-
compatible version of AD7656A. The AD7656A-1 contains six
16-bit, fast, low power successive approximation ADCs in a
package designed on the iCMOS® process (industrial CMOS).
iCMOS is a process combining high voltage silicon with submicron
CMOS and complementary bipolar technologies. It enables the
development of a wide range of high performance analog ICs,
capable of 33 V operation in a footprint that no previous
generation of high voltage devices could achieve. Unlike analog
ICs using conventional CMOS processes, iCMOS components
can accept bipolar input signals while providing increased
performance, which dramatically reduces power consumption
and package size.
The AD7656A-1 features throughput rates of to 250 kSPS. It
contains wide bandwidth (4.5 MHz), track-and-hold amplifiers
that can handle input frequencies up to 4.5 MHz.
1 _{Protected by U.S. Patent No. 6,731,232.}
Rev. 0
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The conversion process and data acquisition are controlled
using the CONVST x signals and an internal oscillator. Three
CONVST x pins (CONVST A, CONVST B, and CONVST C)
allow independent, simultaneous sampling of the three ADC
pairs. The AD7656A-1 has a high speed parallel and serial
interface, allowing the device to interface with microprocessors
or digital signal processors (DSPs). In serial interface mode, the
AD7656A-1 has a daisy-chain feature that allows multiple
ADCs to connect to a single serial interface. The AD7656A-1
can accommodate true bipolar input signals in the ±4 × VREF
range and the ±2 × VREF range. The AD7656A-1 also contains
an on-chip 2.5 V reference.
Multifunction pin names may be referenced by their relevant
function only.
PRODUCT HIGHLIGHTS
1. Six 16-bit, 250 kSPS ADCs on board.
2. Six true bipolar, high impedance analog inputs.
3. High speed parallel and serial interfaces.
4. Reduced decoupling requirements and reduced bill of
materials cost compared with the AD7656A.
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