Part A
AD637ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7762 PCS
- Package
- SOIC-16
- Series
- PMIC - RMS para DC Converters
Replacement verdict
Compatible functional replacement candidate
The AD637BR is a higher-grade variant of the AD637ARZ true RMS-to-DC converter, sharing the same function, package, and pinout while offering improved accuracy specifications. It is a viable functional replacement candidate, though the tighter grade tolerances should be validated against the application's accuracy budget.
Function and Topology
High match
Package and Pinout
High match
Accuracy Grade
Validation required
Supply and Temperature Range
High match
Parts at a glance
Part B
AD637BR
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4669 PCS
- Package
- SOIC-16
- Series
- PMIC - RMS para DC Converters
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD637ARZ | AD637BR | Why it matters |
|---|---|---|---|
| Grade / Accuracy Grade | A grade | B grade | The B grade offers tighter guaranteed accuracy specifications than the A grade, which directly affects measurement precision in RMS-to-DC conversion applications. |
| Total Error (RMS/DC Conversion) | ±0.5% max (A grade) | ±0.25% max (B grade) | Lower total conversion error means more accurate true RMS readings; the B grade is preferable where higher measurement accuracy is required. |
| Nonlinearity | ±0.1% max (A grade) | ±0.05% max (B grade) | Nonlinearity determines how consistently the device converts signals across the input range; the B grade provides better linearity for demanding measurement tasks. |
| Operating Temperature Range (specified) | 0°C to +70°C (commercial) | -40°C to +85°C (industrial) | The wider industrial temperature range of the B grade allows use in harsher environments and ensures specified performance over a broader temperature span. |
| Package / Mounting | 20-Lead SOIC (R-20, surface mount) | 20-Lead SOIC (R-20, surface mount) | Both share the same SOIC footprint, so they are physically interchangeable on an existing PCB layout. |
| Supply Voltage Range | ±3 V to ±18 V (dual supply) | ±3 V to ±18 V (dual supply) | Identical supply requirements mean either part can drop into the same power rail design without modification. |
| Input Signal Bandwidth | 8 MHz (typical, at 200 mV rms) | 8 MHz (typical, at 200 mV rms) | Matching bandwidth ensures both parts handle the same high-frequency RMS measurement range. |
| Quiescent Supply Current | 2.2 mA typical | 2.2 mA typical | Equivalent current draw means no change in power budget when substituting one grade for the other. |
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 | AD637ARZ | AD637BR |
|---|---|---|
| Part Status | Active | Obsolete |
| Supply Current | 2.2 mA | 2.2 mA |
| Voltage - Supply | ±3V ~ 18V | ±3V ~ 18V |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the main differences between the AD637ARZ and AD637BR?
Both devices are RMS-to-DC converters in the same 16-lead SOIC package (R-16) and share the same core function, but they differ in grade and specified accuracy. The AD637ARZ is the A-grade version, while the AD637BR is the B-grade version, which offers tighter accuracy specifications. The AD637BR is specified with lower maximum total error over its operating temperature range than the AD637ARZ.
Are the AD637ARZ and AD637BR pin-compatible?
Yes. Both the AD637ARZ and AD637BR are offered in the same 16-lead SOIC (R-16) package with identical pin assignments, so they are pin-compatible and can use the same PCB land pattern.
What accuracy grade does each part correspond to?
The AD637ARZ corresponds to the A grade of the AD637, and the AD637BR corresponds to the B grade. The B grade provides tighter guaranteed accuracy than the A grade, so the AD637BR is the higher-precision option of the two.
Can the AD637ARZ be replaced by the AD637BR in an existing design?
Because both parts share the same package, pinout, and core RMS-to-DC function, the AD637BR can generally serve as a higher-grade replacement for the AD637ARZ. The substitution should still be validated against the manufacturer datasheet for the specific accuracy, supply, and operating conditions of the target design.
Do both parts operate from the same supply voltages?
Yes. The AD637ARZ and AD637BR are both members of the AD637 family and are specified for the same dual-supply operating range defined in the AD637 datasheet. Designers should confirm the exact supply limits and conditions in the official datasheet for the chosen grade.
What is the difference in operating temperature range between the two grades?
Both the AD637ARZ and AD637BR are specified over the industrial temperature range of −40°C to +85°C. The grade difference between the A and B versions is in guaranteed accuracy, not in the specified temperature range.
Which part should be selected for a precision measurement application?
For applications requiring tighter guaranteed accuracy, the AD637BR (B grade) is the appropriate choice because it carries tighter error specifications than the AD637ARZ (A grade). The AD637ARZ remains suitable where the A-grade accuracy is sufficient for the design.