Part A
AD7655ASTZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1730 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7655ASTZRL and AD7654AST are both 16-bit successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a comparable architecture and supply scheme. However, they differ in channel configuration and throughput, so the AD7654AST can serve as a functional substitute only where the system's input multiplexing and sampling-rate requirements align with its dual-channel, lower-speed design.
Channel Configuration
Validation required
Sampling Rate
Validation required
Package Type
High match
Resolution
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 | AD7655ASTZRL | AD7654AST | Why it matters |
|---|---|---|---|
| Number of ADC Channels | 2 (dual, simultaneous sampling) | 2 (dual, simultaneous sampling) | Both are dual simultaneous-sampling ADCs, so channel count alone does not differentiate them for substitutability. |
| Resolution | 16 bits | 16 bits | Identical resolution means both provide the same nominal measurement precision, a key functional match. |
| Sampling Rate | 500 kSPS | 500 kSPS | Matching throughput ensures either part can meet the same signal bandwidth and timing requirements. |
| Input Type | Pseudo-differential (single-ended inputs referenced to a common) | Pseudo-differential (single-ended inputs referenced to a common) | Same input configuration allows direct substitution in the analog front end without redesign. |
| Supply Voltage (Analog) | 5 V | 5 V | Identical analog supply requirements mean the same power rail can be reused. |
| Interface | Parallel and serial (SPI/QSPI/MICROWIRE/DSP) | Parallel and serial (SPI/QSPI/MICROWIRE/DSP) | Same digital interface options allow either part to connect to the same host processor without glue logic changes. |
| Package | 48-lead LQFP | 48-lead LQFP | Identical package and pinout enable drop-in board replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range means both suit the same environmental conditions. |
| Internal Reference | Yes (2.5 V on-chip reference) | Yes (2.5 V on-chip reference) | Both include an internal reference, simplifying design and supporting equivalent full-scale accuracy. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7655ASTZRL | AD7654AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 1M | 500k |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 2, 4 | - |
| Input Type | Pseudo-Differential, Single Ended | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | MUX-S/H-MUX-ADC | - |
| Ratio - S / H: ADC | 2:1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | Simultaneous Sampling | - |
Frequently asked questions
What are the key architectural differences between the AD7655ASTZRL and the AD7654AST?
The AD7655ASTZRL is a 16-bit, 1 MSPS, dual-channel simultaneous-sampling successive-approximation (SAR) ADC with two on-chip track-and-hold amplifiers and a flexible parallel/serial interface. The AD7654AST is a 16-bit, 500 kSPS, dual-channel simultaneous-sampling SAR ADC with two on-chip track-and-hold amplifiers. The primary differences are throughput (1 MSPS vs. 500 kSPS) and the corresponding internal timing and power characteristics.
Are the AD7655ASTZRL and AD7654AST pin-compatible?
Both devices are offered in a 48-lead LQFP package, but pin compatibility must be confirmed against the respective manufacturer pinout diagrams. The AD7655ASTZRL and AD7654AST share the same package family, yet the pin functions and configuration options differ, so a direct drop-in replacement should not be assumed without verifying each pin against the official datasheets.
What is the maximum sampling rate of each device?
The AD7655ASTZRL supports a maximum throughput of 1 MSPS. The AD7654AST supports a maximum throughput of 500 kSPS. Both are 16-bit SAR converters with simultaneous sampling on two channels.
Do both parts support simultaneous sampling of two channels?
Yes. Both the AD7655ASTZRL and the AD7654AST are dual-channel, simultaneous-sampling SAR ADCs. Each device contains two on-chip track-and-hold amplifiers that acquire both inputs at the same instant, which is suitable for applications requiring phase-coherent measurement of two signals.
What digital interfaces do these ADCs provide?
The AD7655ASTZRL provides a flexible parallel interface and a serial interface, selectable by configuration. The AD7654AST provides a parallel interface and a serial interface as well. Designers should consult the official datasheets for the exact interface modes, word lengths, and timing specifications of each part.
What are the analog input voltage ranges for these devices?
Both the AD7655ASTZRL and the AD7654AST support selectable analog input ranges, typically including 0 V to 5 V, 0 V to 10 V, ±5 V, and ±10 V, configured through the device's input range selection. The exact range options and their accuracy specifications should be verified in the respective manufacturer datasheets.
Can the AD7654AST be used as a drop-in replacement for the AD7655ASTZRL?
No, a drop-in replacement is not recommended without validation. Although both are 16-bit dual simultaneous-sampling SAR ADCs in a 48-lead LQFP package, they differ in maximum throughput (1 MSPS vs. 500 kSPS), timing, and possibly pin configuration. The system timing, interface configuration, and PCB layout must be re-verified against the AD7654AST datasheet before substitution.
What are the typical applications for these dual simultaneous-sampling ADCs?
Both the AD7655ASTZRL and the AD7654AST are suited to applications requiring simultaneous acquisition of two channels, such as motor control, power monitoring, data acquisition systems, and industrial instrumentation. The higher 1 MSPS rate of the AD7655ASTZRL supports faster control loops, while the 500 kSPS AD7654AST suits lower-speed, cost-sensitive designs.