Part A
AD7686BRMZ
ADI公司
- Lifecycle
- Active
- Stock
- 2475 件
- Package
- TFSOP-10
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Compatible functional replacement candidate
The AD7686BRMZ and AD7685CRM are both 16-bit successive-approximation ADCs from the same Analog Devices PulSAR family, sharing a 10-lead MSOP footprint and comparable serial interface, making the AD7685CRM a viable functional replacement candidate for the AD7686BRMZ in many designs. However, the two parts differ in throughput rate and reference configuration, so the system timing budget and external reference circuitry must be validated before substitution.
Resolution and ADC Architecture
High match
Package and Pinout
High match
Sample Rate
Validation required
Reference Configuration
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 | AD7686BRMZ | AD7685CRM | Why it matters |
|---|---|---|---|
| Resolution | 16 bits | 16 bits | Both converters provide 16-bit resolution, so the achievable measurement precision and LSB size are equivalent. |
| Sampling Rate | 500 kSPS | 250 kSPS | The maximum throughput differs; the AD7686 supports twice the sample rate, which affects bandwidth and timing budget in the application. |
| Input Type | Pseudo-differential (single-ended) | Pseudo-differential (single-ended) | Both accept pseudo-differential inputs, so the analog front-end topology and reference connection scheme remain compatible. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible serial | SPI / QSPI / MICROWIRE / DSP compatible serial | Identical serial interface protocols allow the same digital host and firmware to drive either part. |
| Supply Voltage (VDD) | 5 V | 5 V | Matching analog supply requirements mean the same power rail can be reused without redesign. |
| Package | 10-lead MSOP | 10-lead MSOP | Same package and pinout enable a drop-in footprint replacement on an existing PCB. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings ensure both parts suit the same industrial operating environments. |
| Power Consumption | ~15 mW at 5 V, 500 kSPS | ~10 mW at 5 V, 250 kSPS | Lower power in the AD7685 benefits thermally constrained or battery-powered designs, while the AD7686 trades power for speed. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7686BRMZ | AD7685CRM |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 500k | 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 | 5V | - |
| Voltage - Supply, Digital | 5V | - |
Frequently asked questions
What are the key differences between the AD7686BRMZ and AD7685CRM?
The AD7686BRMZ is a 16-bit, 500 kSPS PulSAR ADC, while the AD7685CRM is a 16-bit, 250 kSPS PulSAR ADC. Both are offered in 10-lead MSOP packages and use a pseudo-differential input with a 0 V to VREF range, but the AD7686 provides twice the throughput of the AD7685. The AD7686BRMZ is specified for operation from a 5 V supply, whereas the AD7685CRM is specified for a 2.7 V to 5.5 V supply range.
Are the AD7686BRMZ and AD7685CRM pin-compatible?
Yes. Both devices are available in the same 10-lead MSOP (RM) package and share the same pinout, including VDD, REF, IN+, IN-, GND, CNV, SDO, SCK, and SDI. This allows a common PCB footprint, but the differing supply and throughput specifications must still be validated for the target design.
What is the maximum sampling rate of each device?
The AD7686BRMZ supports a maximum throughput of 500 kSPS. The AD7685CRM supports a maximum throughput of 250 kSPS. Both are successive-approximation register (SAR) ADCs with no pipeline delay.
What supply voltage does each ADC require?
The AD7686BRMZ is specified for a single 5 V supply (VDD). The AD7685CRM is specified for a single supply from 2.7 V to 5.5 V. The digital interface supply (VIO) on both devices supports 1.8 V to 5 V logic, allowing direct connection to low-voltage digital hosts.
Do both parts use the same serial interface?
Yes. Both the AD7686BRMZ and AD7685CRM use a SPI-compatible serial interface with CNV, SCK, SDO, and SDI pins. The interface supports daisy-chain operation and is compatible with 1.8 V to 5 V logic, so the same host interface can be used for either device.
What is the input configuration of these ADCs?
Both devices use a pseudo-differential input structure with an IN+ and IN- pin. The input range is 0 V to VREF, where VREF is applied externally to the REF pin. The AD7686BRMZ and AD7685CRM both require an external reference and do not include an internal reference.
Can the AD7685CRM be used as a drop-in replacement for the AD7686BRMZ?
Not unconditionally. Although the package and pinout are the same, the AD7685CRM has a lower maximum throughput (250 kSPS versus 500 kSPS) and a wider supply range (2.7 V to 5.5 V versus 5 V). A replacement is only valid if the system's sampling rate and supply voltage requirements are satisfied by the AD7685CRM's specifications.
What are the operating temperature ranges for these devices?
Both the AD7686BRMZ and AD7685CRM are specified over the industrial temperature range of -40°C to +85°C. This should be confirmed against the latest manufacturer datasheet for the specific grade ordered.