Part A
ADR421BRZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4766 ПКС
- Package
- SOIC-8
- Series
- PMIC - Справочник напряжения
Replacement verdict
Compatible functional replacement candidate
The ADR421ARZ and ADR421BRZ are functionally interchangeable voltage reference ICs sharing the same package, pinout, output voltage, and operating temperature range; the BRZ grade offers tighter initial accuracy and lower temperature coefficient, making it a valid drop-in candidate where the tighter specifications are acceptable or beneficial.
Output Voltage
High match
Package Type
High match
Operating Temperature Range
High match
Initial Accuracy and Temperature Coefficient
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 | ADR421BRZ | Why it matters |
|---|---|---|---|
| Initial Accuracy (Vout tolerance) | ±0.12% (max) | ±0.04% (max) | Tighter initial tolerance reduces or eliminates the need for system calibration and directly affects output voltage precision at room temperature. |
| Temperature Coefficient | 10 ppm/°C (max) | 3 ppm/°C (max) | Lower tempco means the reference voltage drifts less over temperature, which is critical for precision measurement and industrial applications. |
| Output Voltage Noise (0.1 Hz to 10 Hz) | 1.75 µV p-p (typ) | 1.75 µV p-p (typ) | Low-frequency noise limits resolution in high-resolution ADCs and precision instrumentation; both grades share the same typical noise. |
| Long-Term Drift | 50 ppm/1000 hr (typ) | 50 ppm/1000 hr (typ) | Long-term stability determines how often a system needs recalibration over its lifetime; both grades are specified identically. |
| Output Current Capability | 10 mA (source/sink) | 10 mA (source/sink) | Determines the load the reference can drive directly without an external buffer; identical for both grades. |
| Supply Voltage Range | 4.5 V to 18 V | 4.5 V to 18 V | Defines compatibility with the system power rail; both parts support the same wide supply range. |
| Operating Temperature Range | −40°C to +125°C | −40°C to +125°C | Confirms both parts are rated for industrial/extended temperature environments; identical ratings. |
| Package | 8-Lead SOIC (R-8) | 8-Lead SOIC (R-8) | Same package footprint allows drop-in board replacement without layout changes. |
| Supply Current | 0.8 mA (typ) | 0.8 mA (typ) | Quiescent current affects power budget in low-power designs; both grades draw the same typical current. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADR421BRZ | ADR421ARZ |
|---|---|---|
| Series | XFET® | XFET® |
| Part Status | Active | Active |
| Reference Type | Series | Series |
| Output Type | Fixed | Fixed |
| Voltage - Output (Min/Fixed) | 2.5V | 2.5V |
| Current - Output | 10 mA | 10 mA |
| Tolerance | ±0.04% | ±0.12% |
| Temperature Coefficient | 3ppm/°C | 10ppm/°C |
| Noise - 01 Hzto10 Hz | 1.75µVp-p | 1.75µVp-p |
| Voltage - Input | 4.5V ~ 18V | 4.5V ~ 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 is the main difference between the ADR421ARZ and ADR421BRZ?
The primary difference is the initial accuracy grade. The ADR421ARZ (A grade) specifies an initial output voltage error of ±0.04% maximum, while the ADR421BRZ (B grade) specifies a tighter ±0.02% maximum initial error. Both are 2.500 V precision voltage references in an 8-lead SOIC package.
Are the ADR421ARZ and ADR421BRZ pin-compatible and package-compatible?
Yes. Both devices are offered in the same 8-lead SOIC (R-8) package with identical pin functions, so they are drop-in compatible from a footprint and pinout perspective. The difference is the grade and associated specifications, not the package.
How do the temperature coefficient specifications compare between the A and B grades?
The ADR421ARZ (A grade) specifies a temperature coefficient of 10 ppm/°C maximum, while the ADR421BRZ (B grade) specifies a tighter 3 ppm/°C maximum over the operating temperature range. This makes the B grade preferable for applications requiring tighter drift over temperature.
Do the ADR421ARZ and ADR421BRZ differ in long-term stability or noise performance?
No. Long-term stability and output noise specifications are common to both grades. Both specify long-term stability of 50 ppm per 1000 hours typical and low-frequency output noise of 1.75 µV p-p typical (0.1 Hz to 10 Hz). The grades differ in initial accuracy and temperature coefficient, not in these parameters.
What is the output voltage and operating supply range for these references?
Both the ADR421ARZ and ADR421BRZ provide a fixed 2.500 V output. They operate from a supply voltage of 4.5 V to 18 V and can source up to 10 mA and sink up to 10 mA of output current, making them suitable for a wide range of precision data acquisition and converter applications.
Can the ADR421BRZ be used as a direct replacement for the ADR421ARZ in an existing design?
Yes, in most cases. Because the B grade is a higher-precision version of the same device with identical pinout, package, and functional specifications, it can replace the A grade directly. The B grade offers tighter initial accuracy and temperature coefficient, so it meets or exceeds the A grade specifications. Verify that the tighter specifications do not adversely affect any calibrated system behavior.
Which grade should be selected for a high-accuracy application?
For high-accuracy applications, the ADR421BRZ is the better choice because of its ±0.02% maximum initial accuracy and 3 ppm/°C maximum temperature coefficient. The ADR421ARZ, with ±0.04% initial accuracy and 10 ppm/°C maximum temperature coefficient, is suitable for applications with less stringent precision requirements or where cost is a primary consideration.