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 AD7685BRMZ and AD7686BRMZ are functionally interchangeable 16-bit successive-approximation ADCs sharing the same MSOP-10 package, pinout, and 5 V supply architecture, with the primary distinction being the serial interface logic level (3-wire versus SPI/QSPI/MICROWIRE/DSP-compatible). The AD7686BRMZ is a viable replacement candidate for the AD7685BRMZ in most designs, provided the host interface timing and digital I/O levels are validated against the target system.
Resolution and Architecture
High match
Package and Pinout
High match
Digital Interface Type
Validation required
Supply Voltage Range
High match
Parts at a glance
Part B
AD7685BRMZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1331 PCS
- Package
- TFSOP-10
- Series
- Data Acquisition - 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 | AD7686BRMZ | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 16 | Both are 16-bit ADCs, so resolution is identical and not a differentiator for substitutability. |
| Sampling Rate (max) | 250 kSPS | 500 kSPS | The AD7686 offers twice the throughput, which matters for higher-bandwidth signal acquisition. |
| Input Type | Pseudo-differential (single-ended) | Pseudo-differential (single-ended) | Both use the same pseudo-differential input architecture, so signal conditioning requirements are equivalent. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible | SPI / QSPI / MICROWIRE / DSP compatible | Identical serial interface means the same host controller and firmware can drive either part. |
| Supply Voltage (VDD) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Same supply range allows drop-in use in the same power rail design. |
| Package | 10-lead MSOP | 10-lead MSOP | Identical package and pinout enable direct PCB footprint compatibility. |
| Power Consumption (typical) | 3.5 mW at 5 V, 250 kSPS | 7 mW at 5 V, 500 kSPS | The AD7686 consumes more power proportional to its higher throughput, affecting thermal and energy budgets. |
| INL (max) | ±1.5 LSB | ±1.5 LSB | Matching linearity specifications indicate comparable accuracy performance. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range supports use in identical environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7686BRMZ | AD7685BRMZ |
|---|---|---|
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 500k | 250k |
| Number of Inputs | 1 | 1 |
| Input Type | Pseudo-Differential | Pseudo-Differential |
| Data Interface | SPI, DSP | SPI, DSP |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 2.3V ~ 5.5V |
| Voltage - Supply, Digital | 5V | 2.3V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7685BRMZ and AD7686BRMZ?
The AD7685BRMZ is a 16-bit, 250 kSPS PulSAR analog-to-digital converter, while the AD7686BRMZ is a 16-bit, 500 kSPS PulSAR ADC. Both are pin-compatible in the 10-lead MSOP (RMZ) package and share the same serial interface, but the AD7686 offers twice the throughput rate. The AD7685 provides lower power consumption at its lower sample rate.
Are the AD7685BRMZ and AD7686BRMZ pin-compatible?
Yes. Both devices are offered in the same 10-lead MSOP (RMZ) package with identical pin functions, including VDD, VIO, GND, IN+, IN-, REF, CNV, SDO, SCK, and SDI. This allows a common PCB footprint, though firmware timing must be validated for the higher throughput of the AD7686.
What is the maximum sample rate of each device?
The AD7685BRMZ supports a maximum throughput of 250 kSPS. The AD7686BRMZ supports a maximum throughput of 500 kSPS. Both are 16-bit successive-approximation PulSAR ADCs.
Do both parts use the same serial interface?
Yes. Both the AD7685BRMZ and AD7686BRMZ use a SPI-compatible serial interface with CNV, SCK, SDO, and SDI signals, supporting both CS and chain modes. The interface timing scales with the respective throughput rate, so the AD7686 requires faster SCK timing to achieve 500 kSPS.
How does power consumption compare between the two?
Both devices operate from a 2.7 V to 5.5 V VDD supply with a separate VIO supply. Power consumption scales with throughput; the AD7685BRMZ, at its lower 250 kSPS rate, consumes less power than the AD7686BRMZ operating at 500 kSPS. Exact power figures should be taken from the respective manufacturer datasheets.
Can the AD7686BRMZ be used as a drop-in replacement for the AD7685BRMZ?
Because both are pin-compatible 16-bit PulSAR ADCs in the same 10-lead MSOP package, the AD7686BRMZ can generally replace the AD7685BRMZ on an existing footprint. However, the system must be validated for the higher 500 kSPS throughput, including serial clock timing, digital host capability, and power budget, against the manufacturer datasheets.
What is the resolution and architecture of these ADCs?
Both the AD7685BRMZ and AD7686BRMZ are 16-bit, successive-approximation register (SAR) analog-to-digital converters using Analog Devices' PulSAR architecture, offering no missing codes and a pseudo-differential input structure.