Part A
AD7684BRMZRL7
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 6195 PCS
- Package
- MSOP-8
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7685CRMZ and AD7684BRMZRL7 are both 16-bit successive-approximation ADCs from Analog Devices in MSOP-10 packages, sharing a compatible serial interface and supply architecture. However, they differ in channel configuration and throughput, so the AD7684BRMZRL7 can serve as a functional substitute for the AD7685CRMZ only where a single differential input and lower sample rate are acceptable; designers should validate input configuration and timing against the target application before committing to the swap.
Channel Configuration
Validation required
Sample Rate
Validation required
Resolution
High match
Package Type
High match
Parts at a glance
Part B
AD7685CRMZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 5270 PCS
- Package
- MSOP-10
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | AD7685CRMZ | AD7684BRMZRL7 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 16 | Both are 16-bit ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Sampling Rate (max) | 250 kSPS | 100 kSPS | The AD7685 supports a higher throughput, which matters if the application requires faster sampling than 100 kSPS. |
| Number of Input Channels | 1 (single-ended) | 1 (differential) | Input configuration differs: single-ended versus differential affects signal conditioning, noise immunity, and board design. |
| Input Type | Single-ended | Differential | Differential inputs reject common-mode noise and suit low-level signals, while single-ended inputs simplify wiring for ground-referenced signals. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible | SPI / QSPI / MICROWIRE / DSP compatible | Both use a serial interface, so digital host compatibility is similar and not a barrier to substitution. |
| Supply Voltage (analog) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Identical analog supply range means both can operate from the same system rails. |
| Package | 10-Lead MSOP | 8-Lead MSOP | Different pin counts and footprints mean the PCB layout must be redesigned; they are not drop-in replacements. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range, so environmental suitability is equivalent. |
| Power Consumption (typical) | 3.5 mW at 5 V, 250 kSPS | 3.5 mW at 5 V, 100 kSPS | Similar power draw, but the AD7685 delivers higher throughput for comparable power, affecting efficiency in portable designs. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7684BRMZRL7 | AD7685CRMZ |
|---|---|---|
| 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 | 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 AD7685CRMZ and AD7684BRMZRL7?
The AD7685CRMZ is a 16-bit, 250 kSPS PulSAR analog-to-digital converter with a pseudo-differential input, housed in a 10-lead MSOP package. The AD7684BRMZRL7 is a 16-bit, 100 kSPS fully differential PulSAR ADC in an 8-lead MSOP package. Key differences include sampling rate (250 kSPS vs 100 kSPS), input configuration (pseudo-differential vs fully differential), package pin count (10-lead vs 8-lead), and serial interface timing.
Are the AD7685CRMZ and AD7684BRMZRL7 pin-compatible?
No. The AD7685CRMZ uses a 10-lead MSOP package, while the AD7684BRMZRL7 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 AD7685CRMZ supports a throughput of up to 250 kSPS. The AD7684BRMZRL7 supports a throughput of up to 100 kSPS. The higher sampling rate of the AD7685CRMZ makes it suitable for faster signal acquisition applications.
How do the input configurations of the two ADCs differ?
The AD7685CRMZ provides a pseudo-differential input structure, while the AD7684BRMZRL7 provides a fully differential input structure. The fully differential input of the AD7684BRMZRL7 can offer improved common-mode rejection and better performance with differential signal sources, whereas the pseudo-differential input of the AD7685CRMZ references the negative input to a fixed level.
Do both parts use the same serial interface?
Both devices provide an SPI-compatible serial interface for connection to digital hosts such as DSPs and microcontrollers. However, because the AD7685CRMZ is a 10-lead device and the AD7684BRMZRL7 is an 8-lead device, the exact pin assignments and timing details differ and must be verified against the respective datasheets before designing the digital interface.
What is the resolution and typical supply voltage for these ADCs?
Both the AD7685CRMZ and AD7684BRMZRL7 are 16-bit successive-approximation PulSAR ADCs. Both operate from a single 2.7 V to 5.5 V supply, with the digital interface logic supply also configurable to match the host system. Designers should confirm exact supply and reference requirements from the manufacturer datasheets.
Can the AD7684BRMZRL7 be used as a replacement for the AD7685CRMZ in an existing design?
Not directly. The two parts differ in package footprint (8-lead vs 10-lead MSOP), maximum throughput (100 kSPS vs 250 kSPS), and input configuration (fully differential vs pseudo-differential). A replacement would require PCB redesign, revalidation of the analog front end, and confirmation that the lower 100 kSPS rate meets the system requirements.