AD7903 Datasheet, PDF (1/29 Pages) Analog Devices – Dual Differential 16-Bit, 1 MSPS PulSAR ADC 12.0 mW in QSOP

Data Sheet
Dual Differential 16-Bit, 1 MSPS
PulSAR ADC 12.0 mW in QSOP
AD7903
FEATURES
GENERAL DESCRIPTION
16-bit resolution with no missing codes
Throughput: 1 MSPS
Low power dissipation
7.0 mW at 1 MSPS (VDD1 and VDD2 only)
12.0 mW at 1 MSPS (total)
140 µW at 10 kSPS
INL: ±0.5 LSB typical, ±2.0 LSB maximum
SINAD: 93.5 dB at 1 kHz
THD: −112 dB at 1 kHz
True differential analog input range: ±VREF
0 V to VREF with VREF between 2.4 V to 5.1 V
Allows use of any input range
Easy to drive with the ADA4941-1
No pipeline delay
Single-supply 2.5 V operation with 1.8 V/2.5 V/3 V/5 V logic
interface
Serial port interface (SPI)/QSPI/MICROWIRE/DSP compatible
20-lead QSOP package
Wide operating temperature range: −40°C to +125°C
APPLICATIONS
Battery-powered equipment
Communications
Automated test equipment (ATE)
Data acquisition
Medical instrumentation
Redundant measurement
Simultaneous sampling
The AD7903 is a dual 16-bit, successive approximation, analog-
to-digital converter (ADC) that operates from a single power
supply, VDDx, per ADC. It contains two low power, high speed,
16-bit sampling ADCs and a versatile serial port interface (SPI).
On the CNVx rising edge, the AD7903 samples the voltage
difference between the INx+ and INx− pins. The voltages on
these pins usually swing in opposite phases between 0 V and
VREF. The externally applied reference voltage of the REFx pins
(VREF) can be set independently from the supply voltage pins,
VDDx. The power of the device scales linearly with throughput.
Using the SDIx inputs, the SPI-compatible serial interface can
also daisy-chain multiple ADCs on a single 3-wire bus and provide
an optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V,
or 5 V logic, using the separate VIOx supplies.
The AD7903 is available in a 20-lead QSOP package with operation
specified from −40°C to +125°C.
Table 1. MSOP 14-/16-/18-Bit PulSAR® ADCs
100
Bits kSPS
250
kSPS
400 kSPS 1000
to 500 kSPS kSPS
18
AD7691¹ AD7690¹
AD7982¹
16 AD7680 AD7685¹ AD7686¹
AD7683 AD7687¹ AD7688¹
AD7684 AD7694 AD7693¹
14 AD7940 AD7942¹ AD7946¹
AD7980¹
AD7903
AD7902
ADC
Driver
ADA4941-1
ADA4841-x
ADA4941-1
ADA4841-x
1 _{Pin-for-pin compatible.}
FUNCTIONAL BLOCK DIAGRAM
REF = 2.5V TO 5V
2.5V
ADA4941-1
REF
±10V, ±5V, ...
REF
ADA4941-1
±10V, ±5V, ...
REF1 REF2 VDD1 VDD2
IN1+
ADC1
IN1–
VIO1
SDI1
SCK1
CNV1
SDO1
IN2+
ADC2
IN2–
VIO2
SDI2
SCK2
CNV2
SDO2
GND AD7903
VIO1/VIO2
SDI1/SDI2
SCK1/SCK2
CNV1/CNV2
SDO1
3-WIRE OR 4-WIRE
INTERFACE
(SPI, CS, AND
CHAIN MODES)
SDO2
Figure 1.
Rev. B
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