Part A
AD7685BCPZRL7
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4541 PCS
- Package
- LFCSP-10
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7685BCPZRL7 and AD7685ACPZRL are functionally interchangeable 16-bit PulSAR ADCs sharing identical resolution, architecture, and interface characteristics; the only meaningful distinction is the specified INL grade, so the ACPZRL variant can serve as a higher-accuracy substitute for the BCPZRL in most designs, provided the tighter linearity specification is acceptable and the application does not depend on the relaxed B-grade tolerance.
Resolution and Architecture
High match
Package and Pinout
High match
Digital Interface
High match
INL Grade
Validation required
Parts at a glance
Part B
AD7685ACPZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 8171 PCS
- Package
- VFDFN-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 | AD7685BCPZRL7 | AD7685ACPZRL | 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 | 250 kSPS | Identical throughput means either part can meet the same acquisition timing requirements. |
| Number of Inputs / Channels | 1 (single-ended) | 1 (single-ended) | Same channel configuration allows direct replacement in single-channel signal chains. |
| Input Type | Pseudo-differential | Pseudo-differential | Matching input topology ensures the same analog front-end design can be reused. |
| Interface | SPI / DSP / QSPI / MICROWIRE compatible | SPI / DSP / QSPI / MICROWIRE compatible | Identical serial interface means no firmware or host-controller changes are needed. |
| Supply Voltage (Analog & Digital) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Same supply range allows operation from the same rails without redesign. |
| Package / Case | 10-Lead LFCSP (3 mm x 3 mm) | 10-Lead LFCSP (3 mm x 3 mm) | Identical footprint and package enable drop-in PCB replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same temperature rating ensures equivalent environmental robustness. |
| INL (Integral Nonlinearity) | ±0.6 LSB typ (B grade) | ±0.6 LSB typ (A grade) | Grade-dependent linearity spec; verify the exact grade tolerance to confirm accuracy requirements are met. |
| DNL (Differential Nonlinearity) | ±0.5 LSB typ (B grade) | ±0.5 LSB typ (A grade) | Grade-dependent DNL affects no-missing-code performance; confirm grade tolerance for critical designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7685BCPZRL7 | AD7685ACPZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 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 | 2.3V ~ 5.5V | 2.3V ~ 5.5V |
| Voltage - Supply, Digital | 2.3V ~ 5.5V | 2.3V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What is the difference between the AD7685BCPZRL7 and the AD7685ACPZRL?
Both are 16-bit, 250 kSPS PulSAR analog-to-digital converters in a 10-lead LFCSP package. The primary difference is the grade: the AD7685BCPZRL7 is the B-grade with a maximum INL of ±1.5 LSB, while the AD7685ACPZRL is the A-grade with a maximum INL of ±3 LSB. Both are specified over the −40°C to +85°C industrial temperature range.
Are the AD7685BCPZRL7 and AD7685ACPZRL pin-compatible and package-compatible?
Yes. Both parts are offered in the same 10-lead LFCSP (CP-10) package with identical pin functions, so they share the same PCB land pattern and are footprint-compatible. The difference is limited to the linearity grade, not the package or pinout.
Can the AD7685ACPZRL be used as a drop-in replacement for the AD7685BCPZRL7?
Functionally and footprint-wise, yes, since both are 16-bit 250 kSPS PulSAR ADCs in the same 10-lead LFCSP with the same pinout. However, the A-grade has a wider INL specification (±3 LSB max versus ±1.5 LSB max for the B-grade), so the replacement is only acceptable if the application's accuracy budget tolerates the looser linearity specification. Verify against the datasheet before substituting.
What are the key AC performance specifications shared by both parts?
Both the AD7685BCPZRL7 and AD7685ACPZRL are 16-bit, 250 kSPS successive-approximation ADCs with a pseudo-differential input, an internal 2.5 V reference option, and a serial SPI-compatible interface. They share the same throughput, resolution, and supply configuration; the specified grade difference is in integral nonlinearity (INL).
What supply voltage and reference configuration do these ADCs require?
Both parts operate from a single 2.7 V to 5.5 V supply (VDD) with a separate VIO supply for the digital interface, and they support either an internal 2.5 V reference or an external reference. The analog input range is 0 V to VREF with a pseudo-differential input structure. Confirm exact limits in the AD7685 datasheet for the specific grade.
What interface do the AD7685BCPZRL7 and AD7685ACPZRL use for data output?
Both devices provide a serial, SPI/QSPI/MICROWIRE/DSP-compatible interface for reading conversion results, with a CS and SCLK-based readout. The interface timing and digital I/O behavior are common to both grades because they share the same silicon design and package pinout.
Which grade should be selected for a high-accuracy application?
For tighter linearity, the AD7685BCPZRL7 (B-grade, ±1.5 LSB max INL) is the better choice. The AD7685ACPZRL (A-grade, ±3 LSB max INL) is suitable where the wider linearity tolerance is acceptable. Selection should be based on the error budget of the target design and confirmed against the manufacturer datasheet.