Part A
AD637JR
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6307 PCS
- Package
- SOIC-16
- Series
- PMIC - RMS para DC Converters
Replacement verdict
Compatible functional replacement candidate
The AD637JR and AD637ARZ are functionally equivalent RMS-to-DC converters sharing the same core architecture, pinout, and operating principle, making the AD637JR a viable functional substitute for the AD637ARZ in most applications. The primary distinction lies in the grade-level specifications: the AD637ARZ is specified over the extended industrial temperature range with tighter accuracy tolerances, while the AD637JR is characterized over the commercial temperature range. Designers should validate accuracy and thermal margin requirements against the target application before committing to the commercial-grade device as a direct replacement.
Function and Topology
High match
Pinout and Package
High match
Operating Temperature Range
Validation required
Accuracy Grade
Validation required
Parts at a glance
Part B
AD637ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7762 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 | AD637JR | Why it matters |
|---|---|---|---|
| Package / Case | 16-Lead SOIC (Wide, 300 mil) | 16-Lead SOIC (Wide, 300 mil) | Package footprint and thermal characteristics must match for a drop-in board replacement. |
| Temperature Grade / Operating Range | -40°C to +85°C (industrial) | 0°C to +70°C (commercial) | The wider industrial range of the ARZ allows use in harsher environments where the JR grade may not be specified. |
| Accuracy (RMS Conversion Error) | ±0.5% max (0.2% typical) | ±0.5% max (0.2% typical) | RMS conversion accuracy directly determines measurement fidelity in true-RMS applications. |
| Supply Voltage Range | ±3 V to ±18 V (dual supply) | ±3 V to ±18 V (dual supply) | Compatible supply range ensures the part can operate in the same circuit rails without redesign. |
| Bandwidth (RMS) | 8 MHz (at 200 mV rms) | 8 MHz (at 200 mV rms) | Bandwidth determines the maximum input frequency the RMS converter can accurately process. |
| Quiescent Supply Current | 2.2 mA typical | 2.2 mA typical | Supply current affects power budget and thermal loading in the target design. |
| Input Voltage Range | 0 to 7 V rms (with ±15 V supplies) | 0 to 7 V rms (with ±15 V supplies) | Input range defines the maximum signal amplitude the converter can handle without clipping. |
| Output Buffer / dB Output | On-chip buffer amplifier and dB output | On-chip buffer amplifier and dB output | Integrated buffer and dB output simplify external circuitry and enable logarithmic measurements. |
| RoHS / Lead-Free Status | RoHS compliant, lead-free | RoHS compliant, lead-free | Compliance status affects regulatory acceptance and solder process compatibility. |
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 | AD637JR | AD637ARZ |
|---|---|---|
| Part Status | Obsolete | Active |
| 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 AD637JR?
The AD637ARZ and AD637JR are both AD637 true RMS-to-DC converters from Analog Devices, but they differ in grade and package. The AD637ARZ is the A-grade version in a 16-lead SOIC (R-16) package, specified over the industrial temperature range of −40°C to +85°C. The AD637JR is the J-grade version in a 16-lead SOIC package, specified over the commercial temperature range of 0°C to +70°C. The A-grade offers tighter accuracy specifications than the J-grade.
Are the AD637ARZ and AD637JR functionally interchangeable?
Both devices are AD637 true RMS-to-DC converters with the same core function and pinout in the 16-lead SOIC package. However, they are not drop-in equivalents in all applications because the AD637ARZ is specified over the industrial temperature range (−40°C to +85°C) with tighter accuracy grades, while the AD637JR is specified over the commercial range (0°C to +70°C). Substitution should be validated against the accuracy and temperature requirements of the target design.
What is the difference in accuracy between the AD637ARZ and AD637JR?
The AD637ARZ is the higher-grade A version, which Analog Devices specifies with tighter accuracy tolerances than the J-grade AD637JR. The A grade provides better guaranteed accuracy for the RMS computation and related specifications. Designers requiring tighter accuracy over the industrial temperature range should select the AD637ARZ, while the AD637JR is intended for commercial-temperature applications where the J-grade tolerances are acceptable.
What temperature ranges do the AD637ARZ and AD637JR support?
The AD637ARZ is specified for operation over the industrial temperature range of −40°C to +85°C. The AD637JR is specified for the commercial temperature range of 0°C to +70°C. Applications exposed to sub-zero or elevated ambient temperatures should use the AD637ARZ to remain within the manufacturer's specified operating conditions.
Do the AD637ARZ and AD637JR use the same package and pinout?
Both the AD637ARZ and AD637JR are offered in the 16-lead SOIC package (R-16 suffix in the ordering code). The pinout for the AD637 in this package is common across grades, so the pin functions are the same. The difference between the two part numbers is the grade (A vs J) and the corresponding accuracy and temperature specifications, not the package or pin assignment.
What is the function of the AD637 true RMS-to-DC converter?
The AD637 is a complete, high-accuracy monolithic true RMS-to-DC converter that computes the root-mean-square value of an input waveform. It provides a DC output proportional to the RMS value of the input signal, supporting accurate measurement of complex waveforms beyond simple averaging converters. Both the AD637ARZ and AD637JR share this core RMS-to-DC conversion function.
Which part should be selected for an industrial-temperature design, AD637ARZ or AD637JR?
For designs that must operate over the industrial temperature range of −40°C to +85°C, the AD637ARZ should be selected because it is specified over that range. The AD637JR is specified only over the commercial range of 0°C to +70°C and is not guaranteed to meet specifications outside that range. Selection should always be confirmed against the latest Analog Devices datasheet.