Part A
AD7685CRMZRL7
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4976 PCS
- Package
- MSOP-10
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The AD7685CRMZRL7 and AD7683ARM are both 16-bit successive-approximation ADCs, but they differ in resolution-critical interface, sampling rate, and package characteristics, so the AD7683ARM cannot be treated as a direct drop-in substitute for the AD7685CRMZRL7 without design validation.
Different sampling rate
Different package type
Different interface timing
Different footprint
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7685CRMZRL7 | AD7683ARM | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 16 | Both are 16-bit ADCs, so nominal resolution is equivalent for substitutability. |
| Sampling Rate (max) | 250 kSPS | 100 kSPS | The AD7685 supports a higher throughput; a slower part may not meet system timing requirements. |
| Number of Input Channels | 1 (single-ended) | 1 (single-ended) | Both are single-channel devices, so channel count is compatible for direct substitution. |
| Input Type | Single-ended | Single-ended | Matching input configuration ensures the same signal conditioning can be reused. |
| Interface | SPI / DSP-compatible serial | SPI / QSPI / MICROWIRE / DSP-compatible serial | Both use serial interfaces, but protocol compatibility with the host controller must be confirmed. |
| Supply Voltage (analog & digital) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Identical supply range allows the same power rail design to be used. |
| Package / Mounting | 10-Lead MSOP (surface mount) | 8-Lead MSOP (surface mount) | Different pin counts and footprints mean the PCB layout must be redesigned for substitution. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings ensure both parts suit the same environmental conditions. |
| Power Consumption (typical) | 3.5 mW at 5 V, 250 kSPS | 4.5 mW at 5 V, 100 kSPS | Power budget and thermal design differ; the AD7683 draws more power at a lower sample rate. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7685CRMZRL7 | AD7683ARM |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 100k |
| 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 AD7685CRMZRL7 and the AD7683ARM?
The AD7685CRMZRL7 is a 16-bit, 250 kSPS PulSAR analog-to-digital converter in a 10-lead MSOP package, while the AD7683ARM is a 16-bit, 100 kSPS PulSAR ADC in an 8-lead MSOP package. The AD7685 offers a higher throughput rate and includes a separate VIO supply pin for flexible logic interfacing, whereas the AD7683 provides a lower sample rate in a smaller pin count package.
Are the AD7685CRMZRL7 and AD7683ARM pin-compatible?
No. The AD7685CRMZRL7 uses a 10-lead MSOP package, and the AD7683ARM uses an 8-lead MSOP package. The pin counts and pin functions differ, so they are not drop-in replacements and require different PCB land patterns.
What is the maximum sampling rate of each device?
The AD7685CRMZRL7 supports a maximum throughput of 250 kSPS. The AD7683ARM supports a maximum throughput of 100 kSPS. Designs requiring higher sample rates should account for this difference.
Do both ADCs use the same serial interface?
Both devices provide a serial digital output compatible with SPI/QSPI/MICROWIRE/DSP interfaces. However, the AD7685CRMZRL7 includes a separate VIO pin that sets the logic interface voltage, while the AD7683ARM derives its digital interface from VDD. This affects how each device is connected in mixed-supply systems.
What are the analog input configurations of these ADCs?
Both the AD7685CRMZRL7 and AD7683ARM are successive-approximation PulSAR ADCs with a pseudo-differential analog input configuration. They sample a single-ended input referenced to a common-mode point, so the input architecture is comparable between the two parts.
Can the AD7683ARM be used as a lower-speed substitute for the AD7685CRMZRL7?
Only after validating the differences. The AD7683ARM has a lower maximum throughput (100 kSPS vs 250 kSPS), a different package (8-lead vs 10-lead MSOP), and no separate VIO supply. Substitution requires confirming that the reduced sample rate, pinout, and supply arrangement meet the target design requirements.
What supply voltages do these devices require?
Both devices operate from a single 2.7 V to 5.5 V analog supply (VDD). The AD7685CRMZRL7 additionally provides a separate VIO supply pin for the digital interface, allowing the logic level to be set independently of VDD, whereas the AD7683ARM's digital interface is referenced to VDD.