Part A
AD8421BRZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1263 PCS
- Package
- SOIC-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8421ARZ-RL is a functionally compatible alternative to the AD8421BRZ, sharing the same instrumentation amplifier architecture, pinout, and supply range. The primary distinction is grade-level accuracy: the BRZ offers tighter gain error, lower offset voltage, and reduced drift, making it preferable for precision applications, while the ARZ-RL is suitable for cost-sensitive designs where the relaxed specifications remain acceptable.
Package and Pinout
High match
Supply Voltage Range
High match
Gain Accuracy Grade
Validation required
Input Offset Voltage
Validation required
Parts at a glance
Part B
AD8421ARZ-RL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4538 PCS
- Package
- SOIC-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8421BRZ | AD8421ARZ-RL | Why it matters |
|---|---|---|---|
| Gain Error (G=1) | 0.01% max | 0.05% max | Lower gain error improves DC accuracy of the amplification stage; the B grade offers tighter guaranteed gain accuracy than the A grade. |
| Input Offset Voltage (RTI) | 25 µV max | 60 µV max | Offset voltage directly adds to the measured signal error; a lower guaranteed offset enables more precise low-level signal measurement. |
| Input Offset Voltage Drift | 0.2 µV/°C max | 0.5 µV/°C max | Drift determines offset stability over temperature; tighter drift specification is critical for precision instrumentation across temperature ranges. |
| Input Bias Current | 0.5 nA max | 1 nA max | Bias current flowing through source impedance creates error voltage; lower bias current benefits high-impedance sensor interfaces. |
| Common-Mode Rejection Ratio (G=1) | 94 dB min | 86 dB min | CMRR determines rejection of common-mode noise and interference; higher guaranteed CMRR improves measurement integrity in noisy environments. |
| Gain Bandwidth Product | 10 MHz typ | 10 MHz typ | Bandwidth sets the maximum signal frequency the amplifier can process at a given gain; both grades share the same core bandwidth. |
| Input Voltage Noise (1 kHz) | 3 nV/√Hz typ | 3 nV/√Hz typ | Low voltage noise is essential for resolving small signals; both grades provide the same low-noise performance. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Defines the environmental range over which specifications are guaranteed; identical for both grades. |
| Package / Mounting | 8-SOIC (tube) | 8-SOIC (tape & reel) | Packaging form affects assembly handling; the -RL suffix denotes tape-and-reel packaging suitable for automated production lines. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8421BRZ | AD8421ARZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Active |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Slew Rate | 35V/µs | 35V/µs |
| -3 dB Bandwidth | 10 MHz | 10 MHz |
| Current - Input Bias | 100 pA | 1 nA |
| Voltage - Input Offset | 25 µV | 60 µV |
| Supply Current | 2mA | 2mA |
| Current - Output / Channel | 65 mA | 65 mA |
| Voltage - Supply Span(Min) | 5 V | 5 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the main differences between the AD8421BRZ and AD8421ARZ-RL?
Both are AD8421 instrumentation amplifiers from Analog Devices in an 8-lead SOIC package. The primary difference is the grade: the AD8421BRZ is the higher-grade B version, while the AD8421ARZ-RL is the A-grade version supplied in tape-and-reel packaging (RL). The B grade offers tighter specifications, notably lower offset voltage, lower offset drift, and higher CMRR than the A grade.
What is the gain bandwidth product of the AD8421?
The AD8421 has a gain bandwidth product of 10 MHz (G = 1 to 1000), as specified in the Analog Devices datasheet for both the A and B grades.
How do the offset voltage specifications compare between the AD8421BRZ and AD8421ARZ-RL?
The AD8421BRZ (B grade) specifies a maximum input offset voltage of 60 µV, while the AD8421ARZ-RL (A grade) specifies a maximum input offset voltage of 150 µV, per the Analog Devices datasheet.
Do the AD8421BRZ and AD8421ARZ-RL differ in gain error and CMRR?
Yes. The B grade (AD8421BRZ) specifies tighter gain error and higher common-mode rejection ratio than the A grade (AD8421ARZ-RL). Designers should consult the Analog Devices datasheet grade-specific tables for the exact limits applicable to each grade.
Are the AD8421BRZ and AD8421ARZ-RL pin-compatible and package-compatible?
Yes. Both parts are offered in the same 8-lead SOIC (R-8) package with identical pin functions, so they are pin-compatible. The -RL suffix on the AD8421ARZ-RL denotes tape-and-reel packing rather than a different package or pinout.
What supply voltage range and quiescent current apply to both grades?
Both the AD8421BRZ and AD8421ARZ-RL operate from a dual supply of ±2.5 V to ±18 V (or equivalent single supply of 5 V to 36 V) and draw a typical quiescent supply current of 2.3 mA, per the Analog Devices datasheet.
Can the AD8421ARZ-RL be used as a drop-in replacement for the AD8421BRZ?
Because they share the same package and pinout, the A grade can be used where the tighter B-grade specifications (offset voltage, drift, CMRR, gain error) are not required. Where the design depends on B-grade limits, substituting the A grade is not acceptable without re-validating performance against the datasheet.
What is the difference in packaging between the two part numbers?
The AD8421BRZ is supplied in standard tube packaging, while the AD8421ARZ-RL is supplied in tape-and-reel (the -RL suffix). Both use the same 8-lead SOIC body; only the shipping format differs.