Part A
AD7683BRMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5609 PCS
- Package
- MSOP-8
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7683BRMZ is a strong functional replacement candidate for the AD7685ARMZ, sharing the same 16-bit SAR architecture, 100 kSPS throughput, pseudo-differential input, and MSOP-8 footprint. Designers should validate the serial interface timing and reference configuration before committing to a drop-in substitution.
Resolution and Throughput
High match
Input Configuration
High match
Package Type
High match
Serial Interface
Validation required
Parts at a glance
Part B
AD7685ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5296 PCS
- Package
- MSOP-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 | AD7685ARMZ | AD7683BRMZ | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Sampling Rate | 250 kSPS | 100 kSPS | The AD7685 supports a higher throughput, which matters if the application requires faster sampling or wider signal bandwidth. |
| Number of Input Channels | 1 (single-ended) | 1 (single-ended) | Both are single-channel devices, so channel count is not a differentiator. |
| Interface Type | SPI / QSPI / MICROWIRE / DSP compatible serial | SPI / QSPI / MICROWIRE / DSP compatible serial | Identical serial interface compatibility means either part can drop into the same digital host interface. |
| Supply Voltage (Analog & Digital) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Same supply range allows operation from common 3 V or 5 V rails without redesign. |
| Input Type | Pseudo-differential (single-ended with reference to GND) | Pseudo-differential (single-ended with reference to GND) | Matching input configuration means the same analog front-end topology can be reused. |
| Package | 10-lead MSOP (RMZ) | 10-lead MSOP (RMZ) | Identical package and pinout simplify PCB layout and allow direct board-level substitution. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range means both suit the same environmental conditions. |
| Power Consumption (Typical) | ~4 mW at 5 V, 250 kSPS | ~3.6 mW at 5 V, 100 kSPS | Lower sampling rate of the AD7683 yields lower typical power, relevant for power-sensitive designs. |
Need help validating a replacement?
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7683BRMZ | AD7685ARMZ |
|---|---|---|
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 100k | 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 | 2.7V ~ 5.5V | 2.3V ~ 5.5V |
| Voltage - Supply, Digital | 2.7V ~ 5.5V | 2.3V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7685ARMZ and AD7683BRMZ?
The AD7685ARMZ is a 16-bit, 250 kSPS PulSAR ADC with a pseudo-differential input, while the AD7683BRMZ is a 16-bit, 100 kSPS PulSAR ADC with a fully differential input. The AD7685 offers a higher throughput rate, whereas the AD7683 provides true differential input capability at a lower sample rate.
Are the AD7685ARMZ and AD7683BRMZ pin-compatible?
No. Both devices are offered in 10-lead MSOP packages, but their pin functions differ. The AD7685 uses a serial interface with a separate SDI configuration pin, while the AD7683 has a different pin assignment for its differential input pair and digital interface. PCB layouts must be designed per each device's respective datasheet pin configuration.
What is the maximum sampling rate of each device?
The AD7685ARMZ supports a maximum throughput of 250 kSPS. The AD7683BRMZ supports a maximum throughput of 100 kSPS. The higher sample rate of the AD7685 makes it preferable for faster signal acquisition requirements.
What input configuration does each ADC support?
The AD7685ARMZ provides a pseudo-differential input structure, where the negative input is typically tied to a reference or ground. The AD7683BRMZ provides a fully differential input, allowing it to reject common-mode noise and improve performance in differential signal chains.
Do both parts use the same external reference voltage?
Both devices use an external reference applied to the REF pin to set the full-scale input range. The reference voltage range and the resulting LSB size should be verified against each device's datasheet, as the input span configuration differs between the pseudo-differential AD7685 and the fully differential AD7683.
What digital interface do these ADCs use?
Both the AD7685ARMZ and AD7683BRMZ use a serial SPI-compatible interface for data output. The AD7685 includes an SDI pin for configuration, while the AD7683 uses a simpler serial readout. Both are compatible with standard SPI, QSPI, and MICROWIRE host controllers.
What are the typical power consumption figures for these devices?
Both devices operate from a single 2.7 V to 5.5 V supply and are designed for low-power operation. The AD7685ARMZ, operating at 250 kSPS, and the AD7683BRMZ, operating at 100 kSPS, have power consumption that scales with throughput. Exact quiescent and active current figures should be taken from the respective manufacturer datasheets.
Can the AD7683BRMZ be used as a drop-in replacement for the AD7685ARMZ?
No. Despite both being 16-bit PulSAR ADCs in 10-lead MSOP packages, they differ in pinout, input configuration, and maximum throughput. A direct drop-in replacement is not possible; the design must be revalidated for pin function, input drive requirements, and timing if substituting one for the other.