ADA4941-1_16 Datasheet, PDF (1/24 Pages) Analog Devices – Single-Supply, Differential, 18-Bit ADC Driver

Data Sheet
FEATURES
Single-ended-to-differential converter
Excellent linearity
Distortion −110 dBc at 100 kHz for VO, dm = 2 V p-p
Low noise: 10.2 nV/√Hz, output-referred, G = 2
Extremely low power: 2.2 mA (3 V supply)
High input impedance: 24 MΩ
User-adjustable gain
High speed: 31 MHz, −3 dB bandwidth (G = +2)
Fast settling time: 300 ns to 0.005% for a 2 V step
Low offset: 0.8 mV maximum, output-referred, G = 2
Rail-to-rail output
Disable feature
Wide supply voltage range: 2.7 V to 12 V
Available in space-saving, 3 mm × 3 mm LFCSP
APPLICATIONS
Single-supply data acquisition systems
Instrumentation
Process control
Battery-power systems
Medical instrumentation
GENERAL DESCRIPTION
The ADA4941-1 is a low power, low noise differential driver for
analog-to-digital converters (ADCs) up to 18 bits in systems
that are sensitive to power. The ADA4941-1 is configured in an
easy-to-use, single-ended-to-differential configuration and
requires no external components for a gain of 2 configuration.
A resistive feedback network can be added to achieve gains greater
than 2. The ADA4941-1 provides essential benefits, such as low
distortion and high SNR that are required for driving high
resolution ADCs.
With a wide input voltage range (0 V to 3.9 V on a single 5 V
supply), rail-to-rail output, high input impedance, and a user-
adjustable gain, the ADA4941-1 is designed to drive single-supply
ADCs with differential inputs found in a variety of low power
applications, including battery-operated devices and single-
supply data acquisition systems.
The ADA4941-1 is ideal for driving the 16-bit and 18-bit
PulSAR® ADCs, such as the AD7687, AD7690, and AD7691.
The ADA4941-1 is manufactured on Analog Devices, Inc.,
proprietary, second-generation, eXtra fast complementary
Single-Supply, Differential,
18-Bit ADC Driver
ADA4941-1
FUNCTIONAL BLOCK DIAGRAM
FB 1
REF 2
V+ 3
OUT+ 4
Figure 1.
8 IN
7 DIS
6 V–
5 OUT–
bipolar (XFCB) process, which enables the amplifier to achieve
18-bit performance on low supply currents.
The ADA4941-1 is available in a small 8-lead LFCSP as well as a
standard 8-lead SOIC and is rated to work over the extended
industrial temperature range, −40°C to +125°C.
–60
–65
–70
–75
–80
–85
–90
–95
–100
–105
–110
–115
–120
–125
–130
–135
–140
0.1
HD3
HD2
V_O = 6V p-p
HD2
V_O = 2V p-p
HD3
1
10
100
FREQUENCY (kHz)
1000
Figure 2. Distortion vs. Frequency at Various Output Amplitudes
Rev. D
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