Datasheet

Low Cost, 4-Channel, 16-Bit 1 MSPS
PulSAR
®
ADC
AD7655
Rev. B
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FEATURES
4-channel, 16-bit resolution ADC
2 track-and-hold amplifiers
Throughput
1 MSPS (normal mode)
888 kSPS (impulse mode)
Analog input voltage range: 0 V to 5 V
No pipeline delay
Parallel and serial 5 V/3 V interface
SPI®/QSPI™/MICROWIRE™/DSP compatible
Single 5 V supply operation
Power dissipation
120 mW typical
2.6 mW @ 10 kSPS
Package
48-lead quad flat package (LQFP)
48-lead frame chip scale package (LFCSP)
Pin-to-pin compatible with the AD7654
Low cost
APPLICATIONS
AC motor control
3-phase power control
4-channel data acquisition
Uninterrupted power supplies
Communications
FUNCTIONAL BLOCK DIAGRAM
CONTROL LOGIC AND
CALIBRATION CIRCUITRY
A/B
16
D[15:0]
BUSY
CS
SER/PAR
OGND
OVDD
DGNDDVDD
SERIAL
PORT
BYTESWAP
RD
AVDD AGND REFxREFGND
PD
RESET
CNVST
INAN
SWITCHED
CAP DAC
AD7655
INA1
IMPULSE
MUX
EOC
INA2
A0
INB1
INBN
INB2
TRACK/HOLD
×2
PARALLEL
INTERFACE
03536-001
CLOCK
MUX
MUX
Figure 1.
Table 1. PulSAR Selection
Type/kSPS
100 to 250
500 to 570
800 to
1000
>1000
Pseudo
Differential
AD7660/
AD7661
AD7650/
AD7652
AD7664/
AD7666
AD7653
AD7667
True Bipolar
AD7663 AD7665 AD7671
True
Differential
AD7675
AD7676
AD7677
AD7621
AD7623
18 Bit
AD7678 AD7679 AD7674 AD7641
Multichannel/
Simultaneous
AD7654 AD7655
GENERAL DESCRIPTION
The AD7655 is a low cost, simultaneous sampling, dual-
channel, 16-bit, charge redistribution SAR, analog-to-digital
converter that operates from a single 5 V power supply. It
contains two low noise, wide bandwidth, track-and-hold
amplifiers that allow simultaneous sampling, a high speed
16-bit sampling ADC, an internal conversion clock, error
correction circuits, and both serial and parallel system interface
ports. Each track-and-hold has a multiplexer in front to provide
a 4-channel input ADC. The A0 multiplexer control input
allows the choice of simultaneously sampling input pairs
INA1/INB1 (A0 = low) or INA2/INB2 (A0 = high). The part
features a very high sampling rate mode (normal) and, for low
power applications, a reduced power mode (impulse) where the
power is scaled with the throughput. Operation is specified
from −40°C to +85°C.
PRODUCT HIGHLIGHTS
1. Multichannel ADC.
The AD7655 features 4-channel inputs with two sample-
and-hold circuits that allow simultaneous sampling.
2. Fast Throughput.
The AD7655 is a 1 MSPS, charge redistribution, 16-bit SAR
ADC with internal error correction circuitry.
3. Single-Supply Operation.
The AD7655 operates from a single 5 V supply. In impulse
mode, its power dissipation decreases with throughput.
4. Serial or Parallel Interface.
Versatile parallel or 2-wire serial interface arrangements
are compatible with both 3 V and 5 V logic.

Summary of content (28 pages)