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 AD7686CCPZRL are both 16-bit, single-channel, successive-approximation ADCs from the Analog Devices PulSAR family, sharing the same LFCSP-10 footprint and serial SPI interface. The AD7686CCPZRL offers a higher throughput rate of 500 kSPS versus 250 kSPS for the AD7685BCPZRL7, making it a viable functional upgrade candidate where the higher sample rate is acceptable. Designers should validate the reference configuration and timing margins before substituting in existing layouts.
Resolution and Architecture
High match
Package and Pinout
High match
Sample Rate
Validation required
Digital Interface
High match
Parts at a glance
Part B
AD7686CCPZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4352 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 | AD7686CCPZRL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 16 | Both are 16-bit ADCs, so resolution is identical and does not affect substitutability. |
| Sampling Rate (SPS) | 250 kSPS | 500 kSPS | The AD7686 offers twice the throughput, which matters for higher-bandwidth signal acquisition. |
| Architecture | SAR | SAR | Both use successive-approximation register architecture, giving similar latency and no pipeline delay. |
| Input Type | Pseudo-differential | Pseudo-differential | Matching input configuration allows similar analog front-end design and signal conditioning. |
| Supply Voltage (V) | 2.7 to 5.5 | 4.5 to 5.5 | The AD7685 supports lower supply voltages, enabling 3.3 V operation that the AD7686 cannot. |
| Interface | SPI / QSPI / MICROWIRE / DSP | SPI / QSPI / MICROWIRE / DSP | Identical serial interface simplifies drop-in digital connectivity with host controllers. |
| Package | 10-Lead LFCSP | 10-Lead LFCSP | Same package and footprint allow direct PCB replacement without layout changes. |
| Operating Temperature Range (°C) | -40 to +85 | -40 to +85 | Equivalent temperature ratings ensure comparable reliability across industrial environments. |
| Power Consumption (mW) | 3.5 (at 2.5 V, 250 kSPS) | 15 (at 5 V, 500 kSPS) | The AD7685 consumes significantly less power, which is critical for portable and low-power 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 | AD7685BCPZRL7 | AD7686CCPZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 500k |
| 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 | 5V |
| Voltage - Supply, Digital | 2.3V ~ 5.5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7685BCPZRL7 and the AD7686CCPZRL?
The AD7685BCPZRL7 is a 16-bit, 250 kSPS PulSAR ADC, while the AD7686CCPZRL is a 16-bit, 500 kSPS PulSAR ADC. Both are pin-compatible in a 10-lead LFCSP package, but the AD7686 offers twice the throughput of the AD7685. The AD7685BCPZRL7 is specified over the −40°C to +85°C industrial temperature range, whereas the AD7686CCPZRL is specified over the 0°C to +70°C commercial temperature range.
Are the AD7685BCPZRL7 and AD7686CCPZRL pin-compatible and package-compatible?
Yes. Both devices are offered in a 10-lead LFCSP (CP-10) package with the same pinout, including VDD, VIO, IN+, IN−, REF, GND, CNV, SDO, SCK, and SDI. This allows a common PCB footprint, but the different speed grades and temperature ranges must still be validated for the target design.
What is the maximum sampling rate of each device?
The AD7685BCPZRL7 supports a maximum throughput of 250 kSPS. The AD7686CCPZRL supports a maximum throughput of 500 kSPS. Both are 16-bit successive-approximation PulSAR ADCs.
Do both parts support the same serial interface?
Yes. Both use a SPI-compatible serial interface with separate CNV, SCK, SDO, and SDI pins, supporting daisy-chain and busy-indicator modes. The interface timing scales with the respective throughput rating, so the AD7686CCPZRL requires faster SCK timing to achieve 500 kSPS.
What are the operating temperature ranges for these two ADCs?
The AD7685BCPZRL7 is rated for the −40°C to +85°C industrial temperature range. The AD7686CCPZRL is rated for the 0°C to +70°C commercial temperature range. Designs requiring operation below 0°C or above +70°C should use the AD7685BCPZRL7 or another appropriately rated grade.
Can the AD7686CCPZRL directly replace the AD7685BCPZRL7 in an existing design?
Pin compatibility allows a common footprint, but a direct replacement requires validating the higher 500 kSPS throughput against the host controller's serial timing, confirming the commercial 0°C to +70°C range is acceptable, and verifying that the reference and analog input drive circuitry support the faster conversion rate. The AD7685BCPZRL7 cannot replace the AD7686CCPZRL where 500 kSPS throughput is required.
What is the resolution and architecture of both devices?
Both the AD7685BCPZRL7 and AD7686CCPZRL are 16-bit, charge-redistribution successive-approximation (SAR) ADCs in the Analog Devices PulSAR family, offering no missing codes and differential analog input capability.