Part A
ADR421BRZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4766 PCS
- Package
- SOIC-8
- Series
- PMIC - Referência à Voltação
Replacement verdict
Compatible functional replacement candidate
The ADR425BRZ and ADR421BRZ are both precision voltage references from the same ADR42x family, sharing an identical SOIC-8 package, series-mode topology, and comparable operating temperature range, making them strong functional replacement candidates. The primary distinction is the output voltage (5.000 V versus 2.500 V), which must be validated against the target circuit's reference requirement before substitution.
Output Voltage
Not compatible
Package Type
High match
Reference Topology
High match
Operating Temperature Range
High match
Parts at a glance
Part B
ADR425BRZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4942 PCS
- Package
- SOIC-8
- Series
- PMIC - Referência à Voltação
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADR425BRZ | ADR421BRZ | Why it matters |
|---|---|---|---|
| Output Voltage | 5.0 V | 2.5 V | The nominal reference voltage must match the system's required reference level; a 5.0 V and 2.5 V part are not directly interchangeable without redesigning the surrounding circuit. |
| Initial Accuracy | ±0.04% (B grade) | ±0.04% (B grade) | Initial accuracy determines the reference error at room temperature and directly affects overall system precision. |
| Temperature Coefficient | 3 ppm/°C (B grade) | 3 ppm/°C (B grade) | Drift over temperature governs accuracy across the operating range; matching tempco ensures comparable stability in precision applications. |
| Output Current Capability | 10 mA (source/sink) | 10 mA (source/sink) | The available output drive current limits how heavily the reference can be loaded while maintaining regulation. |
| Supply Voltage Range | 4.5 V to 18 V | 4.5 V to 18 V | The input supply range must accommodate the system rail while providing sufficient headroom above the output voltage. |
| Supply Current | 0.5 mA typ | 0.5 mA typ | Quiescent current affects power budget, especially in low-power or battery-operated designs. |
| Output Noise (0.1 Hz to 10 Hz) | 3.4 µV p-p typ | 1.75 µV p-p typ | Low-frequency noise limits resolution in high-precision data acquisition; the 2.5 V part exhibits lower absolute noise. |
| Long-Term Drift | 50 ppm/1000 hr typ | 50 ppm/1000 hr typ | Long-term stability determines recalibration intervals and lifetime accuracy of the reference. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Package and pinout compatibility affect whether the part can be dropped into an existing PCB footprint. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADR421BRZ | ADR425BRZ |
|---|---|---|
| Series | XFET® | XFET® |
| Part Status | Active | Active |
| Reference Type | Series | Series |
| Output Type | Fixed | Fixed |
| Voltage - Output (Min/Fixed) | 2.5V | 5V |
| Current - Output | 10 mA | 10 mA |
| Tolerance | ±0.04% | ±0.04% |
| Temperature Coefficient | 3ppm/°C | 3ppm/°C |
| Noise - 01 Hzto10 Hz | 1.75µVp-p | 3.4µVp-p |
| Voltage - Input | 4.5V ~ 18V | 7V ~ 18V |
| Supply Current | 600µA | 600µA |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the ADR425BRZ and ADR421BRZ voltage references?
The ADR425BRZ provides a 5.000 V output, while the ADR421BRZ provides a 2.500 V output. Both are precision low-noise voltage references in the SOIC-8 (R-8) package from Analog Devices, but they differ in output voltage, initial accuracy, and temperature coefficient specifications.
What is the initial accuracy of the ADR425BRZ and ADR421BRZ?
The ADR425BRZ (B grade) offers an initial accuracy of ±0.04% maximum, and the ADR421BRZ (B grade) offers an initial accuracy of ±0.04% maximum, per Analog Devices datasheet specifications.
What temperature coefficient do the ADR425BRZ and ADR421BRZ specify?
Both the ADR425BRZ and ADR421BRZ in the B grade specify a temperature coefficient of 3 ppm/°C maximum over the −40 °C to +125 °C operating range, according to the Analog Devices datasheet.
Are the ADR425BRZ and ADR421BRZ pin-compatible?
Yes. Both devices are offered in the same 8-lead SOIC (R-8) package with the same pinout, so they are pin-compatible. However, because their output voltages differ (5.000 V vs 2.500 V), circuit-level validation is required before substitution.
What is the output voltage noise of the ADR425BRZ and ADR421BRZ?
Per the Analog Devices datasheet, the ADR425BRZ specifies low output voltage noise of approximately 3.4 µV p-p (0.1 Hz to 10 Hz), and the ADR421BRZ specifies approximately 1.75 µV p-p (0.1 Hz to 10 Hz).
What supply voltage and current do the ADR425BRZ and ADR421BRZ require?
Both devices operate from a supply voltage of 4.5 V to 18 V for the ADR425BRZ (5.000 V output) and 4.5 V to 18 V for the ADR421BRZ (2.500 V output), with a typical quiescent supply current of 0.8 mA per the Analog Devices datasheet.
Can the ADR421BRZ be used as a direct drop-in replacement for the ADR425BRZ?
No. Although they share the same SOIC-8 package and pinout, the ADR421BRZ outputs 2.500 V while the ADR425BRZ outputs 5.000 V. A direct replacement would change the reference voltage seen by the load, so the design must be re-evaluated for compliance with the target circuit's requirements.
What are the operating temperature ranges for the ADR425BRZ and ADR421BRZ?
Both the ADR425BRZ and ADR421BRZ are specified for operation over the −40 °C to +125 °C temperature range, per the Analog Devices datasheet.