Part A
AD7685BRMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1331 Stückzahl
- Package
- TFSOP-10
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7685CRM is a functionally compatible replacement candidate for the AD7685BRMZ, sharing the same 16-bit SAR ADC core, 250 kSPS throughput, pseudo-differential input, and MSOP-10 footprint. The primary distinction is the operating temperature grade, so the CRM variant should be validated against the target application's thermal profile before substitution.
Resolution and Throughput
High match
Input Type
High match
Package Type
High match
Operating Temperature Range
Validation required
Parts at a glance
Part B
AD7685CRM
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2917 Stückzahl
- Package
- MSOP-10
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7685BRMZ | AD7685CRM | Why it matters |
|---|---|---|---|
| Resolution | 16 bits | 16 bits | Both converters provide the same 16-bit resolution, so measurement precision is equivalent. |
| Sampling Rate | 250 kSPS | 250 kSPS | Identical throughput allows the same signal bandwidth and system timing to be used. |
| Number of Input Channels | 1 (single-ended) | 1 (single-ended) | Same single-channel architecture means the same analog front-end design applies. |
| Interface Type | SPI / QSPI / MICROWIRE / DSP compatible | SPI / QSPI / MICROWIRE / DSP compatible | Identical serial interface ensures drop-in compatibility with the host controller. |
| Supply Voltage (Analog & Digital) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Same supply range allows the same power rail design and level compatibility. |
| Package / Mounting | 10-Lead MSOP, Surface Mount | 10-Lead MSOP, Surface Mount | Same package and footprint enable direct board-level substitution without layout changes. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +125 °C | The CRM variant supports a wider temperature range, which matters for harsh-environment or automotive-grade applications. |
| INL (Integral Nonlinearity) | ±1.5 LSB max | ±0.6 LSB max | The CRM grade offers tighter linearity, giving better accuracy in precision measurement applications. |
| DNL (Differential Nonlinearity) | ±1.0 LSB max | ±0.5 LSB max | Better DNL in the CRM grade ensures no missing codes and improved monotonicity for critical conversions. |
| Grade / Accuracy Class | B grade | C grade | The C grade is a higher-accuracy bin, so it can replace the B grade where tighter performance is required, though at potentially higher cost. |
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 | AD7685BRMZ | AD7685CRM |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 250k |
| Data Interface | SPI, DSP | SPI, DSP |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 1 | - |
| Input Type | Pseudo-Differential | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 2.3V ~ 5.5V | - |
| Voltage - Supply, Digital | 2.3V ~ 5.5V | - |
Frequently asked questions
What are the key differences between the AD7685BRMZ and AD7685CRM?
Both are 16-bit, 250 kSPS PulSAR analog-to-digital converters in a 10-lead MSOP package. The primary difference is the specified operating temperature range: the AD7685BRMZ is rated for −40°C to +85°C, while the AD7685CRM is rated for −40°C to +125°C. The CRM version is the extended-temperature grade of the same converter core.
Are the AD7685BRMZ and AD7685CRM pin-compatible?
Yes. Both devices are offered in the same 10-lead MSOP (RM) package with identical pin functions, so they are pin-compatible and share the same PCB land pattern.
Do the AD7685BRMZ and AD7685CRM have the same resolution and throughput?
Yes. Both are 16-bit successive-approximation (SAR) ADCs with a maximum throughput of 250 kSPS and use the same internal converter architecture, so resolution and sampling rate are identical.
What is the difference in operating temperature range between the two grades?
The AD7685BRMZ is specified over −40°C to +85°C, and the AD7685CRM is specified over −40°C to +125°C. The CRM grade is intended for applications requiring extended temperature operation.
Do both parts support the same analog input and reference configuration?
Yes. Both devices provide a pseudo-differential analog input and use an external reference (REF) with the same input span configuration, so the analog interface and reference requirements are the same for both grades.
Can the AD7685CRM be used as a drop-in replacement for the AD7685BRMZ?
In most designs, yes, because the two parts are pin-compatible and functionally identical, with the CRM grade offering a wider specified temperature range. The replacement should still be validated against the target design's thermal and accuracy requirements using the manufacturer datasheet.
Do both parts use the same serial digital interface?
Yes. Both the AD7685BRMZ and AD7685CRM use the same SPI-compatible serial interface (with SDI, SDO, SCK, and CNV pins) and support the same daisy-chain and busy-indicator modes.