Part A
AD7686BRMZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2475 PCS
- Package
- TFSOP-10
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7688BRM is a strong functional replacement candidate for the AD7686BRMZ, sharing the same 16-bit SAR architecture, 500 kSPS throughput, pseudo-differential input, and MSOP-10 footprint. Designers should validate the differential input configuration and reference drive requirements before substituting in existing layouts.
Resolution and Throughput
High match
Input Configuration
Validation required
Package and Pinout
High match
Supply and Interface
High match
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 | AD7688BRM | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit ADCs, so resolution is equivalent and does not affect substitutability. |
| Sampling Rate | 500 kSPS | 500 kSPS | Identical throughput means either part can meet the same sampling requirements. |
| Number of Input Channels | 1 (single-ended) | 1 (differential) | Input configuration differs: single-ended versus differential affects signal conditioning and noise performance, so they are not drop-in substitutes. |
| Input Type | Single-ended | Differential (pseudo-differential) | The analog front-end topology must match the sensor or driver circuit; a differential input cannot directly replace a single-ended one without redesign. |
| Supply Voltage (Analog) | 5 V | 5 V | Same analog supply simplifies power rail reuse between the two parts. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible | SPI / QSPI / MICROWIRE / DSP compatible | Identical serial interface allows the same digital host connection and firmware protocol. |
| Package | 10-Lead MSOP | 10-Lead MSOP | Same package footprint enables PCB layout compatibility, though pin functions must still be verified. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings mean both suit the same environmental conditions. |
| Reference Type | External | External | Both require an external voltage reference, so the reference design can be shared. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7686BRMZ | AD7688BRM |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Series | PulSAR® | - |
| Sampling Rate(Per Second) | 500k | - |
| Number of Inputs | 1 | - |
| Input Type | Pseudo-Differential | - |
| Data Interface | SPI, DSP | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Number of A/D Converters | 1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Operating Temperature | -40°C ~ 85°C | - |
Frequently asked questions
What are the key differences between the AD7686BRMZ and the AD7688BRM?
The AD7686BRMZ is a 16-bit, 500 kSPS PulSAR analog-to-digital converter, while the AD7688BRM is a 16-bit, 500 kSPS PulSAR ADC with a different input configuration. The AD7686 offers a pseudo-differential input with a single-ended signal range of 0 V to VREF, whereas the AD7688 provides a true differential input. Both are packaged in a 10-lead MSOP and operate from a 5 V supply, but their input structures and corresponding signal chain requirements differ.
Are the AD7686BRMZ and AD7688BRM pin-compatible?
Both devices are offered in a 10-lead MSOP package, but pin compatibility must be verified against the respective manufacturer pinouts. The analog input pins and reference connections differ between the pseudo-differential AD7686 and the true differential AD7688, so a direct drop-in replacement on an existing PCB is not guaranteed without reviewing the pin functions and external circuit configuration.
What is the maximum sampling rate of these ADCs?
Both the AD7686BRMZ and the AD7688BRM are specified for a maximum throughput of 500 kSPS. This sampling rate is achieved with the standard SPI-compatible serial interface and the specified power supply and reference conditions documented in the respective datasheets.
What is the resolution and architecture of the AD7686BRMZ and AD7688BRM?
Both devices are 16-bit successive-approximation register (SAR) analog-to-digital converters based on the PulSAR architecture. They provide 16-bit no-missing-code performance under the specified operating conditions, making them suitable for precision measurement and industrial data acquisition applications.
What supply voltage and reference requirements apply to these ADCs?
Both the AD7686BRMZ and AD7688BRM operate from a single 5 V analog supply (VDD). The reference voltage (VREF) is applied externally and sets the full-scale input range; the AD7686 input range is 0 V to VREF, while the AD7688 differential input range is ±VREF. The digital interface supply (VIO) supports operation from a separate logic level as specified in the datasheets.
What serial interface do the AD7686BRMZ and AD7688BRM use?
Both converters provide an SPI-compatible serial digital interface for connection to microcontrollers, DSPs, and FPGAs. The interface supports daisy-chain operation and is compatible with standard serial port timing, with the conversion result read out as a 16-bit word. Timing parameters and clock requirements are defined in the respective manufacturer datasheets.
Which applications are better suited to the AD7688BRM versus the AD7686BRMZ?
The AD7688BRM true differential input is advantageous in applications where common-mode noise rejection and improved dynamic performance with differential signal sources are required, such as industrial process control and instrumentation. The AD7686BRMZ pseudo-differential input is suited to single-ended signal chains referenced to ground. Selection should be based on the signal source configuration and the required common-mode rejection in the target design.