Part A
AD7655ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5580 PCS
- Package
- LQFP-48
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7655ASTZ and AD7652ASTZRL are both 16-bit successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a compatible digital interface and reference architecture. The AD7655ASTZ offers a dual-channel simultaneous-sampling front end, while the AD7652ASTZRL is a single-channel device, so the primary functional gap is channel count. Designers substituting the AD7652ASTZRL for the AD7655ASTZ must account for the loss of the second simultaneous-sampling channel, while the reverse substitution provides additional capability with minimal interface redesign. Overall, the pair represents a viable functional replacement candidate with channel configuration as the key differentiator.
Channel Count
Validation required
Resolution
High match
Package Type
High match
Digital Interface
High match
Parts at a glance
Part B
AD7652ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 8882 PCS
- Package
- LQFP-48
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (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 | AD7655ASTZ | AD7652ASTZRL | Why it matters |
|---|---|---|---|
| Number of ADC Channels | 2 (simultaneous sampling) | 1 | Determines how many analog signals can be digitized; the AD7655 supports two simultaneous channels while the AD7652 supports only one, affecting system architecture. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so precision and dynamic range are equivalent for substitutability in this respect. |
| Sampling Rate | 500 kSPS | 500 kSPS | Identical throughput means both can handle the same signal bandwidth requirements. |
| Input Configuration | 4-channel, 2 simultaneous (pseudo-differential) | Single-ended/pseudo-differential, 1 channel | Input topology affects how many sensors can be connected and whether simultaneous sampling is possible. |
| Package / Pin Count | 48-lead LQFP | 48-lead LQFP | Same package and pin count simplifies PCB footprint compatibility, though pin functions may differ. |
| Supply Voltage | 5 V analog (AVDD), 2.7–5.25 V digital (DVDD) | 5 V analog (AVDD), 2.7–5.25 V digital (DVDD) | Matching supply requirements allow reuse of the same power rail design. |
| Interface | Parallel and serial (SPI/QSPI/MICROWIRE/DSP) | Parallel and serial (SPI/QSPI/MICROWIRE/DSP) | Identical digital interfaces enable drop-in compatibility with the same host controller. |
| Internal Reference | Yes (2.5 V) | Yes (2.5 V) | Both include an on-chip reference, reducing external component count equally. |
| Power Consumption | ~120 mW typical | ~90 mW typical | Lower power in the AD7652 may matter for thermally constrained or battery-powered designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7655ASTZ | AD7652ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 1M | 500k |
| Number of Inputs | 2, 4 | 1 |
| Input Type | Pseudo-Differential, Single Ended | Pseudo-Differential |
| Data Interface | SPI, Parallel, DSP | SPI, Parallel, DSP |
| Configuration | MUX-S/H-MUX-ADC | S/H-ADC |
| Ratio - S / H: ADC | 2:1 | 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 |
| Features | Simultaneous Sampling | - |
Frequently asked questions
What are the key differences between the AD7655ASTZ and the AD7652ASTZRL?
The AD7655ASTZ is a dual-channel, 16-bit, 500 kSPS successive-approximation ADC, while the AD7652ASTZRL is a single-channel, 16-bit, 500 kSPS PulSAR ADC. The AD7655 provides two simultaneous-sampling input channels in a 48-lead LQFP package, whereas the AD7652 offers one channel in a 48-lead LQFP package. Both share the same 16-bit resolution and 500 kSPS throughput but differ in channel count and input configuration.
Are the AD7655ASTZ and AD7652ASTZRL pin-compatible?
No. Although both devices are offered in a 48-lead LQFP package, their pinouts differ because the AD7655 is a dual-channel converter and the AD7652 is a single-channel converter. The pin functions and signal assignments are not interchangeable, so a direct drop-in replacement on the same PCB land pattern is not supported without design verification against the respective datasheets.
Do both parts support the same digital interface?
Both devices provide a parallel digital interface and support serial communication modes, but the exact interface configuration and timing differ. The AD7655 offers a parallel 16-bit interface plus serial options, while the AD7652 provides a parallel interface and a serial interface. Designers must confirm the specific interface mode, timing, and control signals against each device's datasheet before reusing a common digital host interface.
What is the throughput and resolution of each device?
Both the AD7655ASTZ and AD7652ASTZRL are 16-bit successive-approximation ADCs with a maximum throughput of 500 kSPS. The AD7655 achieves this with two simultaneously sampled channels, while the AD7652 achieves it with a single channel. Resolution and sample rate are therefore identical, but the effective per-channel throughput differs when both AD7655 channels are used.
Can the AD7652ASTZRL replace the AD7655ASTZ in an existing dual-channel design?
No. The AD7652ASTZRL is a single-channel ADC, so it cannot directly replace the dual-channel AD7655ASTZ where two simultaneous input channels are required. A replacement would require redesigning the analog front end to multiplex or sequence inputs, and revalidating timing, accuracy, and PCB layout against the AD7652 datasheet.
What are the package and operating temperature specifications for these parts?
Both the AD7655ASTZ and AD7652ASTZRL are supplied in a 48-lead LQFP package. The "ASTZ" suffix indicates an industrial temperature range device per Analog Devices' ordering nomenclature. Designers should confirm the exact operating temperature range and package dimensions from the official Analog Devices datasheet for each specific part number before finalizing the design.
Which part is better suited for simultaneous multi-channel sampling?
The AD7655ASTZ is better suited for simultaneous multi-channel sampling because it integrates two ADC channels that sample at the same instant, preserving phase relationships between signals. The AD7652ASTZRL, being single-channel, requires external multiplexing and sequential conversion, which introduces channel-to-channel timing skew and is unsuitable where simultaneous sampling is mandatory.