Part A
AD7685ARMZRL7
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1265 Stückzahl
- Package
- MSOP-10
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7685ARMZRL7 and AD7686BRM share the same 16-bit SAR ADC architecture, MSOP-10 footprint, and serial interface, making them functionally interchangeable in many designs. However, the AD7686BRM offers a higher 500 kSPS throughput versus 250 kSPS for the AD7685ARMZRL7, so timing margins and digital host interface timing should be validated before substituting in speed-critical applications.
Resolution
High match
Package Type
High match
Interface Type
High match
Sampling Rate
Validation required
Parts at a glance
Part B
AD7686BRM
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5866 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 | AD7685ARMZRL7 | AD7686BRM | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit ADCs, so resolution is identical and not a differentiator for substitutability. |
| Sampling Rate | 250 kSPS | 500 kSPS | The AD7686 offers twice the throughput, which matters for higher-bandwidth signal acquisition. |
| Input Type | Pseudo-differential (single-ended) | Differential | Input topology affects signal conditioning, common-mode rejection, and board-level wiring. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible | SPI / QSPI / MICROWIRE / DSP compatible | Identical serial interface simplifies digital-side drop-in compatibility. |
| Supply Voltage (Analog & Digital) | 2.7 V to 5.5 V | 4.5 V to 5.5 V | The AD7685 supports lower supply rails, enabling 3.3 V systems; the AD7686 requires a 5 V rail. |
| Package | 10-lead MSOP (RM) | 10-lead MSOP (RM) | Same package footprint allows physical board compatibility. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings suit the same industrial environments. |
| Power Consumption | ~3.5 mW at 2.5 V, 250 kSPS | ~15 mW at 5 V, 500 kSPS | Lower power in the AD7685 benefits battery-powered or thermally constrained designs. |
| Reference Type | External reference | External reference | Both require an external reference, so reference circuitry can be reused. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7685ARMZRL7 | AD7686BRM |
|---|---|---|
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 500k |
| 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 AD7685ARMZRL7 and the AD7686BRM?
The AD7685ARMZRL7 is a 16-bit, 250 kSPS PulSAR ADC in a 10-lead MSOP package, specified over the −40°C to +85°C industrial temperature range. The AD7686BRM is a 16-bit, 500 kSPS PulSAR ADC in a 10-lead MSOP package, specified over the −40°C to +85°C industrial temperature range. The primary differences are throughput (250 kSPS vs 500 kSPS) and the corresponding serial interface timing and power consumption.
Are the AD7685ARMZRL7 and AD7686BRM pin-compatible?
Both devices are offered in a 10-lead MSOP package with the same pin functions (VDD, VIO, GND, REF, IN+, IN−, CNV, SDO, SCK, and SDI), so they share a common pinout. However, pin compatibility alone does not guarantee interchangeability; the higher throughput of the AD7686BRM requires the host to support the faster serial clock and conversion timing.
What is the resolution and throughput of each device?
Both the AD7685ARMZRL7 and the AD7686BRM are 16-bit successive-approximation PulSAR ADCs. The AD7685ARMZRL7 provides a maximum throughput of 250 kSPS, while the AD7686BRM provides a maximum throughput of 500 kSPS.
What is the analog input configuration of these ADCs?
Both parts feature a differential analog input with a full-scale range of 0 V to VREF, where VREF is the applied reference voltage. The input is sampled by an internal track-and-hold circuit, and the devices support a pseudo-differential input configuration referenced to the IN− pin.
What supply voltages do the AD7685ARMZRL7 and AD7686BRM require?
Both devices operate from a single VDD supply of 2.7 V to 5.5 V and a separate VIO supply of 1.8 V to 5.5 V for the digital interface, allowing direct connection to low-voltage logic. The reference voltage (REF) is applied externally and sets the full-scale input range.
What serial interface do these ADCs use?
Both the AD7685ARMZRL7 and the AD7686BRM use a SPI-compatible serial interface with separate CNV, SCK, SDO, and SDI pins. The interface supports daisy-chain operation and readback of the conversion result, and the maximum SCK frequency must be selected to match the respective throughput of each device.
Can the AD7685ARMZRL7 be used as a drop-in replacement for the AD7686BRM?
Because both parts share the same 10-lead MSOP pinout and 16-bit resolution, the AD7685ARMZRL7 can be considered for designs originally using the AD7686BRM only if the system's sampling rate requirement is 250 kSPS or lower. The designer must verify that the slower throughput, serial timing, and power consumption meet the application requirements against the manufacturer datasheets.
What are the operating temperature ranges for these devices?
Both the AD7685ARMZRL7 and the AD7686BRM are specified for operation over the −40°C to +85°C industrial temperature range, as stated in their respective manufacturer datasheets.