AD7357 Datasheet, PDF (1/17 Pages) Analog Devices – Differential Input,Dual,Simultaneous Sampling, 4.25 MSPS, 14-Bit, SAR ADC

Preliminary Technical Data
FEATURES
Dual 14-bit SAR ADC
Simultaneous Sampling
Throughput rate: 4.25 MSPS Per Channel
Specified for VDD of 2.5 V
Power dissipation:
35 mW at 4.25 MSPS
On-chip reference:
2.048 V ± 0.5% max @ 25°C, 10ppm/°C
Dual conversion with read
High speed serial interface:
SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible
−40°C to +125°C operation
Shutdown mode: 10 µA max
16-lead TSSOP package
Differential Input,Dual,Simultaneous
Sampling, 4.25 MSPS, 14-Bit, SAR ADC
AD7357
FUNCTIONAL BLOCK DIAGRAM
Vdd
Vdrive
AD7357
VINA+
VINA-
14-BIT
T/H
SUCCESSIVE
APPROXIMATION
ADC
SDATAA
REF
BUF
BUF
CO N TR OL
LOGIC
SCLK
CS
VINB+
VINB-
14-BIT
SUCCESSIVE
T/H
APPROXIMATION
ADC
SDATAB
GENERAL DESCRIPTION
The AD7357¹ is a dual, 14-bit, high speed, low power, successive
approximation ADC that operates from a single 2.5 V power supply
and features throughput rates up to 4.25 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
200 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; 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 2.5 V supply and
a 4.25 MSPS throughput rate, the part consumes 14 mA typically.
The part also offers flexible power/throughput rate management
when operating in normal mode as the quiescent current
consumption is so low.
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).
AGND AGND REFGND DGND
Figure 1.
PRODUCT HIGHLIGHTS
1. Two Complete ADC Functions Allow Simultaneous Sampling
and Conversion of Two Channels.
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.
2. High Throughput with Low Power Consumption.
The AD7357 offers a 4.25 MSPS throughput rate with 35 mW
power consumption.
3. The part features two standard successive approximation
ADCs with accurate control of the sampling instant via a
CS input and once off conversion control.
1 _{Protected by U.S. Patent No. 6,681,332}
Table 1: Related Devices.
Generic Resolution
AD7356 12
AD7352 12
Throughput
5MSPS
3MSPS
Analog Input
Differential
Differential
Rev. PrD
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