Part A
AD7663ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5007 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7663ASTZ and AD7661AST are both 16-bit successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a compatible parallel interface and similar analog input architecture, making the AD7663ASTZ a viable functional replacement candidate for the AD7661AST in many designs. However, the two parts differ in sampling rate, power consumption, and specified operating temperature range, so engineers should validate timing margins, thermal budget, and application-specific accuracy requirements before substituting one for the other in production.
Resolution and ADC Architecture
High match
Sampling Rate
Validation required
Power Consumption
Validation required
Package and Pin Configuration
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7663ASTZ | AD7661AST | Why it matters |
|---|---|---|---|
| Resolution | 16 bits | 16 bits | Both are 16-bit SAR ADCs, so nominal resolution is equivalent for substitutability. |
| Sampling Rate | 250 kSPS | 100 kSPS | The AD7663 supports a higher throughput; a slower replacement may not meet timing requirements in fast acquisition systems. |
| Number of Input Channels | 2 (differential) | 1 (single-ended) | Channel count and input topology affect whether the part can directly replace the other in a given signal chain. |
| Input Type | Differential | Single-ended | Differential vs single-ended inputs change noise performance and require different front-end circuitry. |
| Supply Voltage (Analog) | 5 V | 5 V | Matching analog supply simplifies power rail reuse in a drop-in replacement scenario. |
| Interface | Parallel / Serial (SPI-compatible) | Parallel / Serial (SPI-compatible) | Both offer flexible digital interfaces, easing host-side integration when swapping parts. |
| Package | 48-lead LQFP | 48-lead LQFP | Identical package and footprint allow physical board compatibility without layout changes. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±2.5 LSB max | Equivalent linearity ensures comparable accuracy in precision measurement applications. |
| Power Consumption | ~87 mW typical | ~70 mW typical | Lower power in the AD7661 may benefit portable designs, while the AD7663 trades power for speed. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7663ASTZ | AD7661AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 100k |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 1 | - |
| Input Type | Differential | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | True Bipolar | - |
Frequently asked questions
What are the key differences between the AD7663ASTZ and the AD7661AST?
The AD7663ASTZ is a 16-bit, 250 kSPS bipolar input successive-approximation ADC, while the AD7661AST is a 16-bit, 100 kSPS pseudo-differential input SAR ADC. The AD7663ASTZ offers higher throughput and true bipolar input ranges, whereas the AD7661AST provides lower power consumption and a pseudo-differential input structure. Both are housed in 48-lead LQFP packages but differ in speed grade, input configuration, and power dissipation.
Are the AD7663ASTZ and AD7661AST pin-compatible?
Both devices are offered in a 48-lead LQFP package, but pin compatibility cannot be assumed solely from package type. Pin functions, input configurations, and control signal assignments differ between the two parts. A direct drop-in replacement should only be attempted after verifying pinout and function against the respective Analog Devices datasheets.
What are the maximum sampling rates of these two ADCs?
The AD7663ASTZ supports a maximum throughput of 250 kSPS. The AD7661AST supports a maximum throughput of 100 kSPS. Designs requiring higher sampling bandwidth should select the AD7663ASTZ, while the AD7661AST is suited to lower-speed, lower-power applications.
How do the input configurations of the AD7663ASTZ and AD7661AST differ?
The AD7663ASTZ provides true bipolar input ranges, supporting configurations such as ±10 V, ±5 V, and ±2.5 V, making it suitable for industrial signal acquisition. The AD7661AST uses a pseudo-differential input structure with unipolar ranges. The choice depends on whether the application requires bipolar signal handling or unipolar pseudo-differential acquisition.
How does power consumption compare between the AD7663ASTZ and AD7661AST?
The AD7661AST is specified for lower power operation, consistent with its lower 100 kSPS throughput. The AD7663ASTZ, operating at up to 250 kSPS, dissipates more power during conversion. Exact power figures should be taken from the respective Analog Devices datasheets, as they depend on supply configuration and operating mode.
Can the AD7661AST be used as a replacement for the AD7663ASTZ in an existing design?
Direct substitution is not recommended without validation. The AD7661AST has a lower maximum sampling rate (100 kSPS vs. 250 kSPS) and a different input configuration (pseudo-differential unipolar vs. true bipolar). System timing, input range, and firmware may require modification. Replacement should only proceed after confirming all parameters against the manufacturer datasheets.
What interface do the AD7663ASTZ and AD7661AST use for digital communication?
Both devices provide a parallel digital interface for output data and support serial communication modes, consistent with the Analog Devices SAR ADC family. The specific interface timing, word length, and control signals should be verified in the respective datasheets before designing the digital host connection.