Data Sheet
ADA4255
Zero Drift, High Voltage, Programmable Gain
Instrumentation Amplifier with Charge Pump
The zero drift PGIA topology of the ADA4255 self calibrates dc
errors and lower frequency 1/f noise, achieving excellent dc preci-
sion over the entire specified temperature range. The combination
of 36 precision gains ranging from 1/16 V/V to 176 V/V within the
ADA4255 and high voltage, high impedance inputs allow a wide
range of inputs to be scaled to the range of the analog-to-digital
converter (ADC). By integrating all gain setting and level shifting
resistors, the ADA4255 achieves excellent common-mode rejection
ratio (CMRR) performance (111 dB minimum at G = 1 V/V) and
extremely low gain drift (±1 ppm/℃ maximum). This high level of
precision maximizes dynamic range and greatly reduces calibration
requirements in many applications.
FEATURES
► Integrated bipolar charge pump
► Simplified isolation requirements
► Wide input range on low voltage supplies
► Dedicated output amplifier supplies for ADC protection
► Low power: 83 mW (DVDD = 3 V, VDDCP = 5 V)
► 36 precision gains from 1/16 V/V to 176 V/V
► Robust ±60 V protected 2:1 input multiplexer
► Excellent dc precision
► Low input offset voltage: ±14 μV maximum
► Low input offset voltage drift: ±0.08 μV/°C maximum
► Gain calibration via internal memory
► Low gain drift: ±1 ppm/°C maximum
► High CMRR: 111 dB minimum, G = 1 V/V
► Low input bias current: ±1.5 nA maximum at TA = 25℃
► Integrated input EMI filtering
The ±60 V input protection, integrated electromagnetic interferance
(EMI) filtering and various safety features make the ADA4255 an
ideal choice for robust industrial systems. Seven general-purpose
input and output (GPIOx) pins, which can be configured to provide
various special functions, are included in the ADA4255. An excita-
tion current source output is available to bias sensors such as
resistance temperature detectors (RTDs).
The ADA4255 is specified over the −40°C to +105°C temperature
range and is offered in a compact 5 mm × 5 mm, 28-lead LFCSP.
► 7 GPIOx ports with special functions
► Sequential chip select mode
► Excitation current source
► SPI port with checksum (CRC) support
► Internal/external fault detection
SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM
► Compact 28-lead, 5 mm × 5 mm LFCSP
► Specified temperature range: −40°C to +105°C
APPLICATIONS
► Universal process control front ends
► Data acquisition systems
► Test and measurement systems
► System power monitoring
GENERAL DESCRIPTION
The ADA4255 is a precision programmable gain instrumentation
amplifier (PGIA) with integrated bipolar charge pumps. With its inte-
grated charge pumps, the ADA4255 internally produces the high
voltage bipolar supplies needed to achieve a wide input voltage
range (38 V typical with VDDCP = 5 V) without lowering input
impedance. The charge pump topology of the ADA4255 allows
channels to be isolated with only low voltage components, reducing
complexity, size, and implementation time in industrial and process
control systems.
Figure 1. Simplified Functional Block Diagram
COMPANION PRODUCTS
► ADCs: AD4007, AD7768, AD7175-2, AD7124-4
► ADC Drivers: ADA4945-1, LTC6363
► Voltage References: ADR4550, ADR3450, LT6656
► Isolators: ADuM6421A Family, ADuM140D Family
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable "as is". However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to
change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
DOCUMENT FEEDBACK
TECHNICAL SUPPORT