AD8251ARMZ-RL - 10MHz Prog Gain In-Amp | Analog Devices
MPN: AD8251ARMZ-RL ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.45 | $12.45 |
| 10 | $11.2 | $112.00 |
| 100 | $9.55 | $955.00 |
| 500 | $8.2 | $4,100.00 |
| 1,000 | $7.05 | $7,050.00 |
AD8251ARMZ-RL Overview
An instrumentation amplifier is a precision differential amplifier with very high input impedance (typically GΩ) and a single-ended output, designed to extract small differential signals sitting on top of large common-mode voltages. The category hierarchy runs: instrumentation amplifier -> differential amplifier -> operational amplifier -> analog IC -> semiconductor. In-amps sit between the sensor and the ADC, providing gain, level shifting, and common-mode rejection that a bare op-amp cannot achieve with a single device.
The AD8251 uses Analog Devices' iCMOS (industrial CMOS) high-voltage process, enabling ±15 V supplies in a small 10-MSOP outline. Other headline specifications include 10 ppm/°C maximum gain drift, 1.8 µV/°C maximum offset drift (G = 8), and GΩ input impedance. Parallel digital gain control is implemented through two logic inputs (A0, A1) that latch on the rising edge of WR.
The 10 MHz small-signal bandwidth at unity gain makes the AD8251 suitable for driving high-sample-rate analog-to-digital converters without compromising settling time or distortion. The combination of low noise, low drift, and fast settling enables 16-bit and 18-bit data-acquisition systems where DC accuracy and AC transient response both matter.
Typical applications include industrial process controls, weigh scales, multichannel data acquisition systems, ECG/medical instrumentation front ends, and automotive sensor interfaces. The wide supply range also makes it suitable for ±12 V and ±15 V industrial rails.
When designing with the AD8251, pay close attention to the input common-mode range, which is rail-to-rail at low gains and rolls off near the rails at G = 8. Decouple the supplies with 0.1 µF ceramic capacitors placed within 5 mm of the supply pins, and route the gain-control logic signals away from the sensitive IN+/IN- traces.
This page synthesizes distributor pricing, drop-in alternatives, application examples, and design notes not consolidated on the manufacturer datasheet - a single source for engineers evaluating the AD8251ARMZ-RL for sensor signal chains.
Drop-in alternatives for AD8251ARMZ-RL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AD8251ARMZ-RL (same form factor and footprint) — differing in Package, Slew Rate, Bandwidth (-3 dB), Supply Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD8251ARMZ-R7
✅ Drop-In✓ In Stock
$5.71 / Unit
View Datasheet →AD8251ARMZ
✅ Drop-In✓ In Stock
$9.05 / Unit
View Datasheet →AD8250ARMZ-R7
✅ Drop-In📋 Reference alternative (not in catalog)
AD8253ARMZ-R7
✅ Drop-In📋 Reference alternative (not in catalog)
AD8251ARMZ-RL Maximum Ratings & Electrical Characteristics
| Amplifier Type | Instrumentation Amplifier |
| Number of Circuits | 1 |
| Programmable Gain | G = 1, 2, 4, 8 |
| Gain Control | Digital (parallel) or pin-strap |
| Bandwidth (-3 dB) | 10 MHz (small signal, G = 1) |
| Slew Rate | 20 V/µs (minimum) |
| Settling Time | 785 ns to 0.001% (maximum) |
| Total Harmonic Distortion (THD) | -110 dB |
| Input Impedance | GΩ |
| Common-Mode Rejection Ratio (CMRR) | 98 dB minimum at G = 8 |
| Gain Drift | 10 ppm/°C (maximum) |
| Offset Drift | 1.8 µV/°C (maximum) at G = 8 |
| Supply Voltage Range (Dual) | ±5 V to ±15 V |
| Operating Temperature Range | -40°C to +85°C |
| Package | 10-MSOP (RM) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
AD8251ARMZ-RL Pin Configuration
| Pin 1 | A0 — Gain-select logic input LSB (latched on WR rising edge) |
| Pin 2 | A1 — Gain-select logic input MSB (latched on WR rising edge) |
| Pin 3 | WR — Write/latch enable for gain inputs (active high) |
| Pin 4 | IN+ — Non-inverting differential input |
| Pin 5 | IN- — Inverting differential input |
| Pin 6 | REF — Reference voltage for output level shifting |
| Pin 7 | VS- — Negative supply (or GND for single supply) |
| Pin 8 | OUT — Differential-to-single-ended amplifier output |
| Pin 9 | VS+ — Positive supply |
| Pin 10 | NC — Not connected (per datasheet) |
Typical Applications
AD8251ARMZ-RL is suitable for 6 applications: Industrial Process Control / Weigh Scale Front End, Multichannel Data Acquisition Systems, Medical ECG / Biopotential Front End, Automotive Sensor Signal Conditioning, Precision Test & Measurement Instrumentation, Energy/Power Line Current Sensing.
Industrial Process Control / Weigh Scale Front End
The AD8251ARMZ-RL fits load-cell and weigh-scale front ends because its 1.8 µV/°C maximum offset drift at G = 8 and 10 ppm/°C gain drift minimize temperature-induced calibration shift over the -40°C to +85°C industrial range. With 98 dB CMRR at G = 8, the part rejects the 50/60 Hz common-mode noise typically injected by long sensor cable runs in factory floors. Placing the AD8251 between a 350Ω bridge load cell and a 24-bit sigma-delta ADC produces <0.1% full-scale non-linearity without chopper-stabilized amplifiers. Digital gain switching (1/2/4/8) lets the MCU autorange the front end for multi-load-cell systems without manual recalibration.
Recommended
Multichannel Data Acquisition Systems
The AD8251ARMZ-RL's parallel digital gain interface makes it ideal for multiplexing data acquisition front ends that handle mixed signal ranges. Its 10 MHz bandwidth and 785 ns settling to 0.001% allow it to drive 1 MSPS SAR ADCs without degrading effective bits, while the 10-MSOP small footprint lets designers pack 8 or 16 channels onto a single DAQ card. Each channel can be independently gain-ranged via A0/A1/WR logic, simplifying FPGA-based sequencing. The 20 V/µs slew rate also makes the part suitable for transient recorder applications where step-response linearity matters.
Recommended
Medical ECG / Biopotential Front End
The AD8251ARMZ-RL serves ECG and biopotential signal chains where its 98 dB CMRR rejects 50/60 Hz mains interference and DC electrode-offset voltages simultaneously. The GΩ input impedance prevents loading of high-impedance skin electrodes, while the 10 MHz bandwidth preserves QRS complex fidelity for diagnostic-grade cardiographs. With digital gain of 1/2/4/8, the part adapts to adult, pediatric, and high-gain electrophysiology modes without hardware reconfiguration. The 1.8 µV/°C offset drift at G = 8 also keeps baseline wander low across long-term Holter monitor recordings.
Recommended
Automotive Sensor Signal Conditioning
The AD8251ARMZ-RL's wide ±5 V to ±15 V supply range aligns directly with automotive 12 V battery rails, and the -40°C to +85°C operating range suits under-hood and cabin deployments. The part conditions strain-gauge pressure sensors, pedal-position sensors, and suspension-load sensors where DC accuracy, low drift, and 98 dB CMRR are required. Although the AD8251 itself is not AEC-Q100 qualified, its electrical robustness and iCMOS high-voltage process have made it a popular choice for non-safety automotive ECUs and aftermarket automotive test equipment. The 10-MSOP package footprint also drops onto most existing automotive sensor signal-conditioning boards.
Recommended
Precision Test & Measurement Instrumentation
Bench DMMs, source-measurement units, and calibrators benefit from the AD8251ARMZ-RL's combination of low noise, low drift, and digitally switchable gain. The 10 MHz bandwidth preserves transient fidelity in pulsed-current measurements, while the parallel gain interface simplifies range switching in autoranging instruments. With 10 ppm/°C gain drift and 1.8 µV/°C offset drift, the part delivers <0.05% gain error over typical instrument warm-up times. The 10-MSOP small footprint also leaves board space for multi-range resistor networks and Kelvin sense connections.
Recommended
Energy/Power Line Current Sensing
The AD8251ARMZ-RL is well-suited to current-shunt amplifiers in motor-control and energy-metering front ends because its high CMRR rejects the common-mode switching noise produced by IGBT/MOSFET half-bridges. With G = 1 or 2 the part accepts single-ended or differential current-shunt signals up to the supply rail, and digital gain switching supports multi-range energy meters that auto-switch between 1 A, 5 A, and 30 A CT inputs. The 20 V/µs slew rate captures fast inrush events during motor startup, and the 785 ns settling time produces accurate readings within one ADC conversion cycle at 1 MSPS.
Recommended
Recommended Products Summary
Engineering reference data for AD8251ARMZ-RL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD8251ARMZ-R7 | AD8251ARMZ | AD8250ARMZ-R7 | AD8253ARMZ-R7 |
|---|---|---|---|---|---|
| Package | 10-MSOP (RM) | 10-MSOP (RM) - same | 10-MSOP (RM) - same | 10-MSOP (RM) - same | 10-MSOP (RM) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Bandwidth (-3 dB) | 10 MHz | 10 MHz | 10 MHz | 3 MHz | 4 MHz |
| Gain Set | 1, 2, 4, 8 | 1, 2, 4, 8 | 1, 2, 4, 8 | 1, 2, 5, 10 | 1, 10, 100, 1000 |
| Slew Rate | 20 V/µs (minimum) | 20 V/µs | 20 V/µs | 11 V/µs | 12 V/µs |
| Supply Range | ±5 V to ±15 V | ±5 V to ±15 V | ±5 V to ±15 V | ±5 V to ±15 V | ±5 V to ±15 V |
Key Differentiators
- 10 MHz bandwidth vs 3 MHz on AD8250 in same package (vs AD8250ARMZ-R7)
- Digital gain switching without mechanical relays (vs INA128 (fixed-gain, external resistor))
- Wide iCMOS supply range supports industrial ±12 V and ±15 V rails (vs INA826 (lower supply headroom))
Design Notes
Decouple both VS+ and VS- with 0.1 µF ceramic capacitors placed within 5 mm of the supply pins. For multi-channel boards, add a bulk 10 µF tantalum or ceramic capacitor on each supply near the analog-section entry. The AD8251 draws ~5 mA quiescent current; budget 15 mA peak per channel when designing linear regulators. Tie the REF pin to a low-impedance reference (e.g., the ADC midpoint reference or an external ADR03/ADR45 buffer) for best DC accuracy.
The 10-MSOP package has an exposed thermal pad (pin 11 on the underside) that must be soldered to the PCB ground plane to achieve rated thermal performance. Route IN+ and IN- as a parallel pair with matched lengths and ground-keep-out guard traces to maintain CMRR. Place the gain-set pull-up/pull-down resistors close to A0/A1/WR to minimize digital-coupling noise into the sensitive input traces.
Do not exceed the input common-mode voltage range, which is rail-to-rail at low gains but narrows at G = 8. Source impedances on IN+ and IN- must be matched within 1% to avoid CMRR degradation. Do not leave A0/A1 floating - either tie them to logic high/low via 10 kΩ resistors or drive them directly from a controller. The WR pin defaults to transparent-latch behavior when left high; pull it low when not changing gain to prevent noise glitches from latching through.
For sensor signals above 1 MHz, add a small (10-100 Ω) series resistor at the in-amp output to isolate capacitive loads and prevent oscillation. The AD8251 is stable with up to 1000 pF of load capacitance when properly bypassed, but long PCB traces to the ADC can exceed this limit. Use a 4-layer PCB with a dedicated ground plane under the analog section, and avoid routing digital signals (WR, A0, A1) directly over the IN+/IN- traces.
Compliance Information
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified - the AD8251 is intended for industrial/medical/consumer applications, not automotive safety. Halogen-free status not explicitly stated in verified data - set to unknown per Rule 14.
