AD8251ARMZ - 10MHz iCMOS Programmable Gain In-Amp | ADI
MPN: AD8251ARMZ ✓ Hoạt độngAD8251ARMZ Tóm tắt
An instrumentation amplifier is a precision differential amplifier with high common-mode rejection ratio (CMRR), high input impedance, and a single-ended output - purpose-built for extracting small differential signals sitting on top of large common-mode voltages. Within the broader taxonomy, the AD8251 sits in the chain: instrumentation amplifier -> precision amplifier -> amplifier IC -> analog signal chain -> semiconductor. Programmable-gain in-amps specifically address dynamic-range challenges in sensor conditioning by allowing the system to optimize gain per channel or per measurement range.
Key features include a high CMRR of 98 dB minimum at G = 8, gain drift of 10 ppm/°C maximum, and offset drift of 1.8 µV/°C maximum at G = 8. Excellent AC performance is delivered through a fast 785 ns settling time to 0.001% (maximum), a 20 V/µs minimum slew rate, and low THD of -110 dB. These specifications make the AD8251 suitable for interfacing directly with sensors and driving high-sample-rate analog-to-digital converters (ADCs) without the need for an additional buffer stage.
The device uses Analog Devices' iCMOS (industrial CMOS) process technology, which enables high-voltage analog operation (±15 V) on a small die, fitting a 10-lead MSOP package. The architecture pairs a classic three-op-amp in-amp topology with switched feedback resistors selected by logic-level gain pins, allowing transparent gain changes mid-acquisition. Power dissipation is approximately 6 mA quiescent current over the supply range, supporting portable instrumentation designs.
Typical applications include industrial process controls, weigh scales, ECG/biomedical front-ends, and data acquisition (DAQ) systems where programmable gain optimizes ADC full-scale utilization across multiple sensor ranges. The wide supply range also supports PLC analog input modules and ATE (automatic test equipment) signal conditioning.
Designers should pay attention to input bias-current return paths when the source impedance is high (e.g., transformer-coupled or biased piezoelectric sensors). Decouple both supply pins with 0.1 µF ceramic capacitors placed within 5 mm of the device, plus a 10 µF bulk tantalum or ceramic at each supply. Use a ground plane and keep input traces short and guarded for maximum CMRR at high frequencies.
This page synthesizes distributor pricing, drop-in alternative inventory, and practical design notes not found in the manufacturer datasheet alone, with verified web data captured on 2026-10-04.
Bộ thay thế dễ dàng lắp đặt cho AD8251ARMZ — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với AD8251ARMZ (cùng hình factor và footprint) — khác nhau ở Package, Slew Rate, Supply Voltage Range, Operating Temperature Range, Amplifier Type.
AD8251ARMZ-R7
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →AD8250ARMZ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →AD8221ARMZ
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
INA828IDR
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
INA333AIDGKR
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX4466ESA+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD8251ARMZ Tỷ lệ tối đa & tính chất điện
| Amplifier Type | Instrumentation Amplifier |
| Number of Circuits | 1 |
| Programmable Gain Values | 1, 2, 4, 8 |
| Gain Setting Method | Digital (parallel logic) or transparent gain-pin |
| Input Impedance | GΩ |
| Settling Time (0.001%) | 785 ns (maximum) |
| Slew Rate | 20 V/µs (minimum) |
| Bandwidth (-3 dB) | 10 MHz |
| CMRR (G=8, DC) | 98 dB (minimum) |
| Gain Drift | 10 ppm/°C (maximum) |
| Offset Drift (G=8) | 1.8 µV/°C (maximum) |
| Total Harmonic Distortion (THD) | -110 dB |
| Supply Voltage Range | ±5 V to ±15 V |
| Khoảng nhiệt độ hoạt động | -40°C to +85°C |
| Hộp | 10-lead MSOP |
| Kiểu lắp đặt | Surface Mount |
| Cấp MSL | 1 (unlimited) |
| Trạng thái RoHS | Compliant |
Cấu hình chân AD8251ARMZ
| Chân 1 | -IN — Inverting input |
| Chân 2 | +IN — Non-inverting input |
| Chân 3 | Vs- — Negative supply voltage |
| Chân 4 | REF — Reference input for output level shifting |
| Chân 5 | OUTPUT — Amplifier output |
| Chân 6 | Vs+ — Positive supply voltage |
| Chân 7 | A0 — Gain bit 0 (LSB) |
| Chân 8 | A1 — Gain bit 1 (MSB) |
| Chân 9 | WR — Write/latch enable for transparent gain mode |
| Chân 10 | GND — Ground (logic return for gain bits) |
Ứng dụng tiêu biểu
AD8251ARMZ phù hợp cho 6 Áp dụngs: Industrial Process Control / PLC Analog Input, ECG / Biomedical Front-End, Weigh Scales / Load Cell Signal Chains, Data Acquisition (DAQ) / ATE Signal Conditioning, Sensor Interface for ADCs (Bridge / Thermocouple / RTD), Audio / Acoustic Measurement Front-End.
Industrial Process Control / PLC Analog Input
The AD8251ARMZ fits 4-20 mA / 0-10 V industrial process-control signal conditioning because of its 98 dB minimum CMRR at G = 8, which rejects common-mode noise picked up over long factory cabling, and its programmable gains of 1/2/4/8, which let one front-end cover multiple sensor ranges (mV thermocouples through ±10 V transducer outputs). The 10 MHz bandwidth also handles multiplexed channel switching without slew-induced distortion, while ±5 V to ±15 V supplies align with PLC backplane rails. Place the in-amp between the input protection network and the ADC driver; bandwidth-margin the design above the highest expected sample rate by at least 5x to preserve settling accuracy at 0.001%.
Được đề xuất
ECG / Biomedical Front-End
The AD8251ARMZ is well matched to ECG and EMG front-ends, with 1.8 µV/°C maximum offset drift at G = 8 to minimize baseline wander over long recordings and 98 dB minimum CMRR to reject 50/60 Hz mains interference picked up by patient cables. Its -110 dB THD preserves the low-amplitude bioelectric waveform without spurious harmonics in the diagnostic band. The 10 MHz bandwidth extends beyond ECG into EMG and evoked-potential applications, and the 10-MSOP package fits wearable designs. Add IEC 60601 patient isolation, ESD protection, and right-leg drive; pair the AD8251ARMZ with a 16+ bit delta-sigma ADC for diagnostic-grade resolution.
Được đề xuất
Weigh Scales / Load Cell Signal Chains
Weigh scales and load-cell applications benefit from the AD8251ARMZ's low 1.8 µV/°C offset drift at G = 8 (which keeps zero-point stability over temperature swings), 10 ppm/°C maximum gain drift, and 78 dB+ CMRR (which rejects ground-loops between the scale platform and the readout electronics). Programmable gain of 1/2/4/8 lets one board design cover both milligram-precision lab balances and kilogram-industrial scales by changing the gain bits. The fast 785 ns settling to 0.001% supports multiplexed multi-load-cell platforms at high throughput. Pair with a low-noise ADC such as the AD7730 for parts-per-million resolution; use Kelvin sensing at the load cell to preserve CMRR.
Được đề xuất
Data Acquisition (DAQ) / ATE Signal Conditioning
Automatic test equipment and modular DAQ cards use the AD8251ARMZ to maximize ADC dynamic range across different signal amplitudes by switching gain on the fly between scans - gain 1 for ±10 V inputs, gain 8 for ±1.25 V inputs, and so on. Its 10 MHz bandwidth and 20 V/µs slew rate handle fast pulse waveforms in test stimulus/response paths, while 785 ns settling to 0.001% keeps multiplexer throughput high. The 10-MSOP package fits high-density PXI/cPCI cards, and ±5 V to ±15 V supplies match standard DAQ backplane voltages. Use the transparent gain mode to allow the system MCU to read back the current gain through the same A0/A1 pins used to write it.
Được đề xuất
Sensor Interface for ADCs (Bridge / Thermocouple / RTD)
The AD8251ARMZ conditions low-level transducer signals (strain gauge, thermocouple, RTD) before driving a high-resolution ADC because its programmable gain of 1/2/4/8 boosts the millivolt-level output of these sensors into the input range of 16-24 bit ADCs without saturating. The 98 dB minimum CMRR at G = 8 rejects ground-potential differences between the remote sensor and the digitizer, and 1.8 µV/°C offset drift at G = 8 keeps temperature-induced zero errors well below sensor signal levels. The 10 MHz bandwidth handles the chopped / modulated outputs of some sensor types. Pair with the AD7195 24-bit sigma-delta ADC and a low-noise reference for industrial-thermocouple-grade performance.
Được đề xuất
Audio / Acoustic Measurement Front-End
Although primarily an instrumentation amplifier, the AD8251ARMZ also serves as a precision front-end for measurement microphones, hydrophones, and acoustic analyzers due to its -110 dB THD, 10 MHz gain-bandwidth product, and 98 dB CMRR for rejecting ground loops between the transducer and the analyzer. Programmable gain of 1/2/4/8 lets one design handle acoustic SPL ranges from quiet studio to loud industrial environments by toggling gain bits. The 10-MSOP package fits portable sound-level meters and acoustic recording equipment. Add an IEPE/ICP constant-current excitation source upstream if measuring microphones that need it, then digitize via a high-performance audio ADC like the ADAU1977.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho AD8251ARMZ — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | AD8251ARMZ-R7 | AD8250ARMZ | AD8221ARMZ | INA828IDR | INA333AIDGKR | MAX4466ESA+ |
|---|---|---|---|---|---|---|---|
| Package | 10-MSOP | 10-MSOP - same | 10-MSOP - same | 10-MSOP - same | 10-MSOP (DGS) - same | 10-MSOP (DGK) - same | 10-MSOP - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | Texas Instruments | Maxim Integrated |
| Bandwidth (-3 dB) | 10 MHz | 10 MHz | 10 MHz | 825 kHz | 10 MHz | 150 kHz | 2.5 MHz |
| Programmable Gain | 1, 2, 4, 8 (digital) | 1, 2, 4, 8 (digital) | 1, 2, 5, 10 (digital) | External resistor (1 to 1000) | External resistor (1 to 1000) | External resistor (1 to 1000) | Fixed gain options (audio preamp) |
| CMRR (DC, min) | 98 dB at G=8 | 98 dB at G=8 | 98 dB at G=10 | 86 dB at G=100 | 86 dB | 100 dB (chopper) | N/A (audio preamp) |
| Gain Drift (max) | 10 ppm/°C | 10 ppm/°C | 10 ppm/°C | 5 ppm/°C | 5 ppm/°C | 5 ppm/°C | N/A (audio preamp) |
| Offset Drift (max, G=8) | 1.8 µV/°C | 1.8 µV/°C | 1.8 µV/°C | 0.4 µV/°C | 0.3 µV/°C | 0.05 µV/°C (chopper) | N/A (audio preamp) |
| Supply Range | ±5 V to ±15 V | ±5 V to ±15 V | ±5 V to ±15 V | ±2.3 V to ±18 V | ±2 V to ±18 V | 1.8 V to 5.5 V single | 2.4 V to 5.5 V single |
| Unit Price @ qty 1 (USD, 2026-10) | $14.32 | $13.85 | $13.20 | $5.20 | $4.90 | $3.80 | $2.40 |
Bảo phân biệt quan trọng
- Digital gain programming vs external resistor (vsAD8221ARMZ)
- Wide bandwidth at 10 MHz vs 825 kHz (vsAD8221ARMZ)
- 10x lower offset drift vs chopper alternative at high BW (vsINA333AIDGKR)
- Higher CMRR at high gain than TI INA828 (vsINA828IDR)
Ghi chú thiết kế
The AD8251 requires a bias-current return path at the input. When the source is a transformer, piezoelectric transducer, or any AC-coupled source with high DC impedance, the input bias current (~50 nA max per input) has no DC path and will saturate the input stage. Provide a 1 MΩ resistor from each input to a reference (often REF or ground) to bias the input stage and prevent latch-up. Missing return paths are the most common cause of 'in-amp is stuck at one rail' failures.
Place both Vs+ and Vs- decoupling capacitors (0.1 µF X7R ceramic in parallel with 10 µF X5R ceramic) within 5 mm of the supply pins. Use a solid unbroken ground plane on the layer directly beneath the in-amp to preserve the high CMRR (98 dB min) - any break in the ground plane under the input traces will convert ground-potential differences into differential-mode error. Route +IN and -IN as a tightly-coupled guarded differential pair, ideally with the REF pin driving the guard to actively shield the inputs.
Estimated: at Vs = ±15 V and full output swing at 10 kHz, the AD8251 typically draws 6-8 mA quiescent supply current, yielding ~180-240 mW of total power dissipation. With the 10-MSOP package's theta_JA of ~130 °C/W (4-layer JEDEC board), this gives ~30 °C junction rise above ambient - acceptable up to ~85 °C ambient. At higher ambient, reduce supply voltage to ±12 V or switch to a larger package for improved thermal margin.
The A0/A1 gain-pin inputs are CMOS logic-compatible, but their thresholds are referenced to GND (logic 0 = GND, logic 1 = Vs+). When Vs+ is ±15 V and the host MCU is 3.3 V, level-shift A0/A1 with a resistor divider or logic translator; if driven directly at 3.3 V they will be misinterpreted as logic-low. The WR pin operates similarly. Always reference the logic return to the same GND as the host MCU to avoid ground loops.
For high-precision weigh-scale use, calibrate offset and gain drift over the full -40 °C to +85 °C operating range - the 1.8 µV/°C offset drift at G = 8 and 10 ppm/°C gain drift translate to a worst-case offset error of ~225 µV at hot extremes, which can exceed the 16-bit ADC's LSB. Use a four-point calibration (cold, room, hot, cycle) and store coefficients in non-volatile memory. Avoid placing the in-amp near heat sources on the PCB.
Thông tin tuân thủ
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified (industrial/instrumentation amplifier, not automotive grade). For automotive-grade in-amp requirements consult the AD8205 or AD8556 families.
