Part A
AD7677ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1648 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7677ASTZ and AD7674ASTZRL are both 18-bit successive-approximation ADCs from Analog Devices in the same LQFP-48 package, sharing a compatible digital interface and reference architecture. However, they differ in maximum throughput rate and analog supply configuration, so the AD7674ASTZRL can serve as a functional substitute for the AD7677ASTZ only after confirming that the system timing budget and power-supply design accommodate the faster conversion rate and differing supply requirements.
Resolution
Validation required
Maximum Throughput Rate
Not compatible
Package Type
High match
Analog Supply Voltage
Validation required
Parts at a glance
Part B
AD7674ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7785 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit 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 | AD7677ASTZ | AD7674ASTZRL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 18 | Higher resolution provides finer quantization and better dynamic range, which directly affects measurement accuracy and substitutability in precision applications. |
| Sampling Rate (SPS) | 1M | 800k | Maximum throughput determines how fast the system can acquire samples; a slower part may not meet timing requirements of the original design. |
| Number of Input Channels | 1 | 1 | Channel count must match the signal path topology; both are single-channel, so this is compatible. |
| Input Type | Differential | Differential | Differential inputs improve noise immunity and common-mode rejection; matching input type ensures the analog front end remains compatible. |
| Architecture | SAR | SAR | Converter architecture affects latency, power, and behavior; both being SAR means similar timing and no pipeline delay characteristics. |
| Supply Voltage (Analog) | 5 V | 5 V | Analog supply must match the board's rail; identical 5 V requirement allows direct substitution without power redesign. |
| Interface | SPI / DSP / Parallel | SPI / DSP / Parallel | Digital interface compatibility is essential for drop-in replacement with the host processor or FPGA. |
| Package / Case | 48-LQFP | 48-LQFP | Identical package and footprint enable physical board compatibility without layout changes. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Matching temperature ratings ensure the replacement meets the same environmental and reliability requirements. |
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 | AD7677ASTZ | AD7674ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Number of Bits | 16 | 18 |
| Sampling Rate(Per Second) | 1M | 800k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential | Differential |
| Data Interface | SPI, Parallel, DSP | SPI, Parallel, 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, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7677ASTZ and AD7674ASTZRL?
The AD7677ASTZ is a 16-bit, 1 MSPS PulSAR analog-to-digital converter, while the AD7674ASTZRL is an 18-bit, 800 kSPS PulSAR ADC. Both are offered in a 48-lead LQFP package and are pin-compatible within the PulSAR family, but they differ in resolution, throughput, and dynamic performance specifications.
Are the AD7677ASTZ and AD7674ASTZRL pin-compatible?
Yes. Both devices are supplied in the same 48-lead LQFP (ST-48) package and share the PulSAR pinout, allowing a common PCB footprint. However, pin compatibility does not guarantee functional equivalence; resolution, sample rate, and timing parameters must be validated against each datasheet before substitution.
What is the maximum sampling rate of each device?
The AD7677ASTZ supports a maximum throughput of 1 MSPS. The AD7674ASTZRL supports a maximum throughput of 800 kSPS. Designs requiring the full 1 MSPS rate cannot substitute the AD7674ASTZRL without reducing the sampling frequency.
What resolution does each ADC provide?
The AD7677ASTZ provides 16-bit resolution with no missing codes. The AD7674ASTZRL provides 18-bit resolution with no missing codes. The higher resolution of the AD7674ASTZRL yields finer LSB size and lower quantization noise for a given input range.
Do both parts support the same analog input range and interface?
Both devices use a differential analog input and provide a serial SPI-/QSPI-/MICROWIRE-compatible interface plus a parallel interface option. The AD7677ASTZ offers a selectable input range of 0 V to 2.5 V or ±2.5 V, while the AD7674ASTZRL offers a selectable input range of 0 V to 2.5 V or ±2.5 V as well. Refer to each datasheet for the exact reference and input-span configuration.
Can the AD7674ASTZRL directly replace the AD7677ASTZ in an existing design?
Direct replacement is possible only after verifying that the system can accept the lower 800 kSPS throughput and that the 18-bit output word length is handled correctly by the digital interface and downstream processing. The higher resolution also changes LSB size and noise floor, so accuracy budgets must be re-evaluated against the AD7674ASTZRL datasheet.
What package and operating temperature range do these devices share?
Both the AD7677ASTZ and AD7674ASTZRL are offered in a 48-lead LQFP package and are specified for the industrial temperature range of −40°C to +85°C. The "RL" suffix on AD7674ASTZRL denotes tape-and-reel packaging rather than a different die or temperature grade.
Which device should be selected for higher dynamic range applications?
The AD7674ASTZRL, with 18-bit resolution, provides a lower LSB size and correspondingly finer quantization than the 16-bit AD7677ASTZ, making it preferable where higher dynamic range and resolution are required, provided the 800 kSPS maximum throughput is sufficient for the application.