Part A
ADR421ARZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 1276 個数
- Package
- SOIC-8
- Series
- PMIC - 電圧リファレンス
Replacement verdict
Compatible functional replacement candidate
The ADR421ARZ and ADR425BR-REEL7 are both precision voltage references from the same ADR42x family, sharing a common SOIC-8 footprint and series-mode topology, so the ADR425BR-REEL7 can serve as a functional replacement candidate for the ADR421ARZ in many designs. However, the two parts differ in output voltage (2.500 V vs 5.000 V) and initial accuracy/temperature coefficient grades, so the replacement must be validated against the target circuit's reference voltage, accuracy budget, and drift requirements before adoption.
Output Voltage
Validation required
Package Type
High match
Reference Topology
High match
Accuracy and Temperature Coefficient
Validation required
Parts at a glance
Part B
ADR425BR-REEL7
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 4500 個数
- Package
- SOIC-8
- Series
- PMIC - 電圧リファレンス
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADR421ARZ | ADR425BR-REEL7 | Why it matters |
|---|---|---|---|
| Initial Accuracy | ±0.04% (max) | ±0.04% (max) | Initial accuracy determines the output voltage error at room temperature; both parts offer the same tight tolerance, so accuracy is not a differentiator. |
| Output Voltage | 2.500 V | 5.000 V | The nominal output voltage must match the system's reference requirement; these parts provide different voltages and are not directly substitutable without redesign. |
| Temperature Coefficient | 3 ppm/°C (max) | 3 ppm/°C (max) | Tempco governs reference drift over temperature; identical values mean both maintain comparable stability across the operating range. |
| Initial Accuracy (B grade) | ±0.04% (A grade) | ±0.04% (B grade) | Grade designation reflects guaranteed accuracy binning; the ADR425B is a higher-grade bin than the ADR421A, affecting guaranteed limits. |
| Output Current Capability | 10 mA (source/sink) | 10 mA (source/sink) | Drive capability determines how much load the reference can supply; equal ratings mean similar loading flexibility. |
| Supply Voltage Range | 4.5 V to 18 V | 7.0 V to 18 V | Minimum supply headroom differs because the 5 V output requires more headroom; this affects compatibility with low-voltage rails. |
| Supply Current | 0.8 mA (typ) | 0.8 mA (typ) | Quiescent current impacts power budget in low-power designs; identical typical values indicate comparable efficiency. |
| Output Noise (0.1 Hz to 10 Hz) | 1.75 µV p-p (typ) | 3.4 µV p-p (typ) | Low-frequency noise affects precision in high-resolution converters; the ADR421 offers lower noise, which may be preferable for sensitive applications. |
| Long-Term Drift | 50 ppm/1000 hr (typ) | 50 ppm/1000 hr (typ) | Long-term stability affects calibration intervals; equal drift means similar maintenance requirements over time. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Package compatibility determines PCB footprint and assembly; identical packages allow drop-in replacement from a mechanical standpoint. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADR421ARZ | ADR425BR-REEL7 |
|---|---|---|
| Series | XFET® | XFET® |
| Part Status | Active | Obsolete |
| Reference Type | Series | Series |
| Output Type | Fixed | Fixed |
| Voltage - Output (Min/Fixed) | 2.5V | 5V |
| Current - Output | 10 mA | 10 mA |
| Tolerance | ±0.12% | ±0.04% |
| Temperature Coefficient | 10ppm/°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 ADR421ARZ and ADR425BR-REEL7 voltage references?
The ADR421ARZ is a 2.500 V precision voltage reference in an 8-lead SOIC package with an initial accuracy of ±0.04% (A grade) and a temperature coefficient of 3 ppm/°C (max). The ADR425BR-REEL7 is a 5.000 V precision voltage reference in an 8-lead SOIC package supplied on tape and reel, with an initial accuracy of ±0.04% (B grade) and a temperature coefficient of 3 ppm/°C (max). The primary differences are output voltage (2.5 V vs 5.0 V), grade designation, and packaging format.
Are the ADR421ARZ and ADR425BR-REEL7 pin-compatible?
Both devices are offered in the same 8-lead SOIC (R-8) package footprint, so the pin assignments and PCB land pattern are compatible. However, because the output voltages differ (2.5 V vs 5.0 V), they are not electrically interchangeable in a given design without verifying that the downstream circuitry accepts the different reference voltage.
What is the initial accuracy specification for each part?
The ADR421ARZ (A grade) has an initial accuracy of ±0.04% maximum. The ADR425BR-REEL7 (B grade) also has an initial accuracy of ±0.04% maximum. Both are specified over the extended industrial temperature range of −40°C to +125°C.
How do the temperature coefficients of the ADR421ARZ and ADR425BR-REEL7 compare?
Both the ADR421ARZ and the ADR425BR-REEL7 are specified with a maximum temperature coefficient of 3 ppm/°C over the −40°C to +125°C operating range, based on the Analog Devices datasheets for the ADR42x family.
What output current can each reference source or sink?
Both the ADR421ARZ and ADR425BR-REEL7 can source up to 10 mA and sink up to 10 mA of output current, per the ADR42x datasheet specifications. Load regulation is specified for these operating conditions.
What is the difference between the A grade and B grade in these part numbers?
In the ADR42x family, the grade letter denotes the initial accuracy and temperature coefficient binning. The ADR421ARZ is an A-grade 2.5 V reference, and the ADR425BR-REEL7 is a B-grade 5.0 V reference. Designers should consult the specific grade tables in the Analog Devices ADR42x datasheet to confirm the exact accuracy and drift limits for each grade before substitution.
What does the REEL7 suffix indicate on the ADR425BR-REEL7?
The REEL7 suffix indicates that the device is supplied in tape-and-reel packaging (7-inch reel) for automated pick-and-place assembly. The ADR421ARZ is supplied in standard tube or tray packaging; the packaging format does not affect the electrical specifications of the device.
Can the ADR421ARZ be used as a drop-in replacement for the ADR425BR-REEL7?
No. Although both are 8-lead SOIC devices from the same ADR42x family, the ADR421ARZ provides a 2.500 V output while the ADR425BR-REEL7 provides a 5.000 V output. A direct substitution would change the reference voltage by a factor of two and is not valid without redesigning or revalidating the affected circuit.