AD7357_15 Datasheet, PDF (1/21 Pages) Analog Devices – Differential Input, Dual, Simultaneous Sampling, 4.2 MSPS, 14-Bit, SAR ADC

Differential Input, Dual, Simultaneous
Sampling, 4.2 MSPS, 14-Bit, SAR ADC
AD7357
FEATURES
Dual 14-bit SAR ADC
Simultaneous sampling
Throughput rate: 4.2 MSPS per channel
Specified for a VDD of 2.5 V
Power dissipation: 36 mW at 4.2 MSPS
On-chip reference: 2.048 V ± 0.25%, 6 ppm/°C
Dual conversion with read
High speed serial interface
SPI-/QSPI-/MICROWIRE-/DSP-compatible
−40°C to +125°C operation
16-lead TSSOP package
Qualified for automotive applications
APPLICATIONS
Automotive radar
Data acquisition systems
Motion control
I and Q demodulation
RFID readers
GENERAL DESCRIPTION
The AD7357¹ is a dual, 14-bit, high speed, low power, successive
approximation analog-to-digital converter (ADC) that operates
from a single 2.5 V power supply and features throughput rates
up to 4.2 MSPS. The part contains two ADCs, each preceded by
a low noise, wide bandwidth track-and-hold circuit that can
handle input frequencies in excess of 110 MHz.
The conversion process and data acquisition use standard
control inputs allowing for easy interfacing to microprocessors
or DSPs. The input signal is sampled on the falling edge of CS; a
conversion is also initiated at this point. The conversion time is
determined by the SCLK frequency.
The AD7357 uses advanced design techniques to achieve very
low power dissipation at high throughput rates. With a 2.5 V
supply and a 4.2 MSPS throughput rate, the part consumes 14 mA
typically. The part also offers flexible power/throughput rate
management options.
The analog input range for the part is the differential common
mode ±VREF/2. The AD7357 has an on-chip 2.048 V reference
that can be overdriven when an external reference is preferred.
The AD7357 is available in a 16-lead thin shrink small outline
package (TSSOP).
V_INA+
V_INA–
REF_A
FUNCTIONAL BLOCK DIAGRAM
V_DD
V_DRIVE
AD7357
T/H
14-BIT
SUCCESSIVE
APPROXIMATION
ADC
SDATA_A
REF
BUF
BUF
CONTROL
LOGIC
SCLK
CS
REF_B
V_INB+
V_INB–
14-BIT
SUCCESSIVE
T/H
APPROXIMATION
ADC
SDATA_B
AGND
AGND
REFGND
Figure 1.
DGND
PRODUCT HIGHLIGHTS
1. Two Complete ADC Functions.
These functions allow simultaneous sampling and conversion
of two channels. The conversion result of both channels is
simultaneously available on separate data lines or in suc-
cession on one data line if only one serial port is available.
2. High Throughput with Low Power Consumption.
The AD7357 offers a 4.2 MSPS throughput rate with
36 mW power consumption.
3. Simultaneous Sampling.
The part features two standard successive approximation
ADCs with accurate control of the sampling instant via a
CS input and once off conversion control.
Table 1. Related Devices
Generic Resolution Throughput
AD7356 12-bit
5 MSPS
AD7352 12-bit
3 MSPS
AD7266 12-bit
2 MSPS
AD7866 12-bit
1 MSPS
AD7366 12-bit
1 MSPS
AD7367 14-bit
1 MSPS
Analog Input
Differential
Differential
Differential/single-ended
Single-ended
Single-ended bipolar
Single-ended bipolar
1 _{Protected by U.S. Patent No. 6,681,332.}
Rev. B
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