Part A
AD7656BSTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3438 PCS
- Package
- LQFP-64
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The AD7656BSTZ and AD7652AST are not drop-in replacements for one another. The AD7656BSTZ is a six-channel simultaneous-sampling bipolar ADC in a 64-lead LQFP, while the AD7652AST is a single-channel unipolar ADC in a 48-lead LQFP. They differ in channel count, input configuration, package footprint, and digital interface, so a direct board-level substitution is not possible without redesign.
Different channel count
Different input configuration
Different footprint
Different digital interface
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7656BSTZ | AD7652AST | Why it matters |
|---|---|---|---|
| Number of ADC Channels | 6 | 1 | Determines how many independent analog signals can be sampled simultaneously; a 6-channel device cannot be substituted by a single-channel device in multi-channel systems. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so precision and dynamic range are equivalent for signal conversion accuracy. |
| Sampling Rate | 250 kSPS | 500 kSPS | Maximum throughput affects the highest frequency signal that can be digitized; the AD7652AST supports faster sampling per channel. |
| Input Type | Single-ended (bipolar) | Single-ended (bipolar) | Input configuration must match the sensor or signal source topology for correct measurement. |
| Supply Voltage | 5 V analog, 5 V digital | 5 V analog, 5 V digital | Supply requirements determine power rail compatibility and whether the part can drop into an existing board design. |
| Interface | Parallel / Serial (SPI) | Parallel | The host microcontroller or FPGA must support the available digital interface; serial-only hosts cannot use the parallel-only AD7652AST. |
| Package | 64-lead LQFP | 48-lead LQFP | Footprint and pin count must match the PCB layout; different packages are not drop-in compatible. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Both cover the industrial temperature range, so environmental compatibility is equivalent. |
| Power Consumption | ~140 mW (typical) | ~90 mW (typical) | Power budget and thermal design differ; the multi-channel AD7656BSTZ consumes more power overall. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7656BSTZ | AD7652AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | iCMOS® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 500k |
| Number of A/D Converters | 6 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 6 | - |
| Input Type | Single Ended | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Architecture | SAR | - |
| Reference Type | External, Internal | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | Simultaneous Sampling, True Bipolar | - |
Frequently asked questions
What are the key differences between the AD7656BSTZ and the AD7652AST?
The AD7656BSTZ is a 16-bit, 6-channel simultaneous-sampling SAR ADC offering 250 kSPS per channel, while the AD7652AST is a 16-bit, single-channel SAR ADC offering 500 kSPS. The AD7656BSTZ is housed in a 64-lead LQFP package, whereas the AD7652AST is housed in a 48-lead LQFP package. The AD7656BSTZ targets multi-phase power monitoring and motor control applications requiring simultaneous sampling, while the AD7652AST targets single-channel high-speed data acquisition.
Can the AD7656BSTZ and AD7652AST be used interchangeably in the same design?
No. The two devices differ in channel count (6 vs. 1), package footprint (64-lead LQFP vs. 48-lead LQFP), pinout, and throughput (250 kSPS vs. 500 kSPS). They are not pin-compatible or functionally interchangeable, and a redesign of the PCB and digital interface would be required to substitute one for the other.
What is the resolution and throughput of each device?
Both devices provide 16-bit resolution. The AD7656BSTZ offers a throughput of 250 kSPS per channel across six simultaneous-sampling channels. The AD7652AST offers a throughput of 500 kSPS on a single channel.
What analog input configuration does each ADC support?
The AD7656BSTZ provides six independent analog input channels that can be configured as either true bipolar or unipolar inputs, supporting simultaneous sampling of all six channels. The AD7652AST provides a single analog input channel with a bipolar input range and a successive-approximation register architecture.
What digital interface do the AD7656BSTZ and AD7652AST use?
Both devices provide a parallel digital interface for connection to a host processor or DSP. The AD7656BSTZ also supports a serial interface mode, allowing flexibility in system architecture. The AD7652AST provides a parallel interface for reading conversion results.
What are the typical applications for each device?
The AD7656BSTZ is typically used in multi-phase power quality monitoring, motor control, and industrial instrumentation where simultaneous sampling of multiple channels is required. The AD7652AST is typically used in single-channel data acquisition systems, medical instrumentation, and general-purpose high-speed signal digitization.
What are the package and pin-count differences between the two devices?
The AD7656BSTZ is supplied in a 64-lead LQFP package. The AD7652AST is supplied in a 48-lead LQFP package. The different pin counts and footprints mean the two devices cannot share the same PCB land pattern.
Do both devices operate from the same supply voltage?
Both devices operate from a 5 V analog supply and a separate digital supply for the interface. The AD7656BSTZ additionally requires a high-voltage supply for its analog input structure to accommodate true bipolar input ranges. Designers should verify the exact supply requirements against the respective manufacturer datasheets before finalizing the power architecture.