Part A
ADR421ARZ
ADI公司
- Lifecycle
- Active
- Stock
- 1276 件
- Package
- SOIC-8
- Series
- PMIC-電壓參攷
Replacement verdict
Compatible functional replacement candidate
The ADR421ARZ and ADR420BR are both precision low-noise voltage references from the same ADR42x family, sharing a common SOIC-8 footprint and series-mode topology, so the ADR420BR can serve as a functional replacement candidate for the ADR421ARZ in many designs. However, the two parts differ in output voltage and initial accuracy grade, so the replacement must be validated against the target circuit's reference voltage, tolerance budget, and thermal drift requirements before adoption.
Output Voltage
Validation required
Package Type
High match
Reference Topology
High match
Initial Accuracy Grade
Validation required
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 | ADR420BR | Why it matters |
|---|---|---|---|
| Initial Accuracy | ±0.04% (max) | ±0.05% (max) | Determines the output voltage error at 25°C; tighter initial accuracy reduces system calibration effort. |
| Output Voltage | 2.500 V | 2.048 V | The nominal reference voltage must match the ADC/DAC full-scale requirement; these parts are not directly interchangeable without scaling. |
| Temperature Coefficient | 3 ppm/°C (max) | 3 ppm/°C (max) | Governs reference drift over temperature; low tempco is critical for precision measurement accuracy across the operating range. |
| Initial Accuracy Grade | A grade | B grade | Grade suffix indicates tested accuracy/tempco binning; mixing grades can shift guaranteed performance limits. |
| Output Current Capability | 10 mA (source/sink) | 10 mA (source/sink) | Defines the load the reference can drive while maintaining regulation; must exceed the ADC/DAC reference input demand. |
| Supply Voltage Range | 4.5 V to 18 V | 4.5 V to 18 V | Must be compatible with the available system rail; both share the same wide input range for design flexibility. |
| Supply Current | 0.8 mA (typ) | 0.8 mA (typ) | Affects total system power budget; low quiescent current is important for portable and low-power designs. |
| Output Noise (0.1–10 Hz) | 1.75 µV p-p (typ) | 1.75 µV p-p (typ) | Low-frequency noise limits achievable resolution in high-precision ADCs; lower noise improves effective number of bits. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Footprint and thermal characteristics must match the PCB layout for drop-in compatibility. |
| Operating Temperature Range | −40°C to +125°C | −40°C to +125°C | Must cover the application's ambient conditions while maintaining specified accuracy and drift limits. |
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 | ADR420BR |
|---|---|---|
| Series | XFET® | XFET® |
| Part Status | Active | Obsolete |
| Mounting Type | Surface Mount | Surface Mount |
| Reference Type | Series | - |
| Output Type | Fixed | - |
| Voltage - Output (Min/Fixed) | 2.5V | - |
| Current - Output | 10 mA | - |
| Tolerance | ±0.12% | - |
| Temperature Coefficient | 10ppm/°C | - |
| Noise - 01 Hzto10 Hz | 1.75µVp-p | - |
| Voltage - Input | 4.5V ~ 18V | - |
| Supply Current | 600µA | - |
| Operating Temperature | -40°C ~ 125°C (TA) | - |
Frequently asked questions
What are the key differences between the ADR421ARZ and ADR420BR?
The ADR421ARZ is a 2.500 V precision voltage reference with an initial accuracy of ±0.04% (max) and a temperature coefficient of 3 ppm/°C (max) over the −40°C to +125°C range, offered in an 8-lead SOIC package. The ADR420BR is a 2.048 V precision voltage reference with an initial accuracy of ±0.05% (max) and a temperature coefficient of 3 ppm/°C (max), also in an 8-lead SOIC package. The primary differences are the output voltage (2.500 V vs 2.048 V) and the initial accuracy grade.
Can the ADR421ARZ and ADR420BR be used interchangeably in a design?
No, they are not directly interchangeable because they provide different output voltages (2.500 V for the ADR421ARZ and 2.048 V for the ADR420BR). A substitution would require revalidation of the reference voltage, system calibration, and any downstream circuitry that depends on the absolute reference value.
What is the output voltage of each device?
The ADR421ARZ provides a fixed 2.500 V output, while the ADR420BR provides a fixed 2.048 V output. Both are members of the ADR42x family of low-noise, high-accuracy voltage references.
What are the initial accuracy specifications for the ADR421ARZ and ADR420BR?
The ADR421ARZ (A grade) has an initial accuracy of ±0.04% maximum. The ADR420BR (B grade) has an initial accuracy of ±0.05% maximum. Both specifications are stated at 25°C per the manufacturer datasheet.
What temperature coefficient do the ADR421ARZ and ADR420BR offer?
Both the ADR421ARZ and ADR420BR are specified with a maximum temperature coefficient of 3 ppm/°C over the −40°C to +125°C operating temperature range, according to the Analog Devices datasheet.
What package do the ADR421ARZ and ADR420BR use?
Both devices are supplied in an 8-lead SOIC package (R suffix in the part number indicates the SOIC package). The pinout is common across the ADR42x family, but the output voltage differs between the two parts.
What are the supply voltage and current requirements for these references?
Both the ADR421ARZ and ADR420BR operate from a supply voltage of 4.5 V to 18 V and typically draw approximately 0.8 mA of quiescent current, per the Analog Devices ADR42x datasheet. The minimum supply must exceed the output voltage by the specified dropout.
What is the output noise performance of the ADR421ARZ and ADR420BR?
Both devices are specified with low output noise of approximately 1.75 µV p-p (0.1 Hz to 10 Hz) typical, per the Analog Devices ADR42x datasheet. This makes them suitable for precision data acquisition and instrumentation applications.