Part A
AD7654ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2675 PCS
- Package
- LQFP-48
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7654ASTZ and AD7653ASTZRL are both 16-bit successive-approximation ADCs from Analog Devices in a 48-lead LQFP package, sharing the same core resolution, supply architecture, and serial interface family. However, they differ in channel configuration and throughput, so the AD7653ASTZRL is a viable functional candidate only where a single-channel, higher-speed converter is acceptable in place of the dual-channel AD7654ASTZ. Designers should validate channel count requirements, sampling rate headroom, and pin-level configuration before committing to a drop-in substitution.
Channel Configuration
Validation required
Sampling Rate
Validation required
Resolution
High match
Package Type
High match
Parts at a glance
Part B
AD7653ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7144 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 | AD7654ASTZ | AD7653ASTZRL | Why it matters |
|---|---|---|---|
| Number of ADC Input Channels | 4 (2 pseudo-differential / 2 single-ended) | 1 (single-ended) | Channel count determines how many signals can be digitized; a 4-channel part cannot be directly substituted where a single-channel signal path is designed, and vice versa. |
| Input Configuration | Pseudo-differential (2 channels) plus single-ended (2 channels) | Single-ended | Pseudo-differential inputs allow rejection of common-mode noise and ground offsets, which single-ended inputs cannot, affecting measurement accuracy in noisy environments. |
| Throughput / Sampling Rate | 500 kSPS | 1 MSPS | Maximum sampling rate limits the bandwidth of signals that can be captured; the faster part supports higher-frequency inputs and faster multiplexed scanning. |
| Resolution | 16 bits | 16 bits | Resolution sets the smallest detectable signal change and the achievable dynamic range; matching resolution is essential for equivalent measurement precision. |
| Package / Pin Count | 48-lead LQFP | 48-lead LQFP | Package and pin count must match for board-level drop-in compatibility; identical packages simplify substitution but pinout differences still require verification. |
| Digital Interface | Parallel (byte/word) and serial SPI-compatible | Parallel (byte/word) and serial SPI-compatible | The host interface must match the system's bus architecture; both offering parallel and serial modes gives flexibility but requires correct mode configuration. |
| Analog Supply Voltage | 5 V | 5 V | Analog supply voltage determines the input signal range and must match the surrounding analog front-end to avoid clipping or level-shifting circuitry. |
| Internal Reference | Yes (2.5 V on-chip reference) | Yes (2.5 V on-chip reference) | An internal reference simplifies design and improves accuracy consistency; matching reference behavior supports equivalent full-scale input ranges. |
| Power Consumption | Typically ~90 mW at 500 kSPS | Typically ~120 mW at 1 MSPS | Power budget and thermal constraints differ between the parts; higher throughput generally costs more power, affecting supply and thermal design. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7654ASTZ | AD7653ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 500k | 1M |
| 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 AD7654ASTZ and the AD7653ASTZRL?
The AD7654ASTZ is a dual-channel, 16-bit, 500 kSPS successive-approximation ADC, while the AD7653ASTZRL is a single-channel, 16-bit, 1 MSPS SAR ADC. The AD7654 provides two simultaneous-sampling input channels, whereas the AD7653 offers one channel at twice the throughput. Both are supplied in a 48-lead LQFP package and operate from a 5 V analog supply with a 2.5 V reference.
Are the AD7654ASTZ and AD7653ASTZRL pin-compatible?
No. Although both devices are housed in a 48-lead LQFP (ST-48) package, their pin functions differ because the AD7654 is a dual-channel converter and the AD7653 is a single-channel converter. The analog input pins, configuration pins, and digital interface assignments are not identical, so the two parts cannot be treated as drop-in replacements without verifying the pinout against the respective datasheets.
What are the maximum sampling rates of the AD7654ASTZ and AD7653ASTZRL?
The AD7654ASTZ supports a maximum throughput of 500 kSPS, and because it has two simultaneously sampled channels, it delivers 500 kSPS per channel. The AD7653ASTZRL supports a maximum throughput of 1 MSPS on its single channel. The higher per-conversion rate of the AD7653 makes it suitable for faster single-channel acquisition, while the AD7654 is intended for applications requiring simultaneous dual-channel sampling.
Do both devices support the same digital interface?
Both converters provide a parallel digital interface and support serial interface modes, but the exact interface configuration and timing differ between the two datasheets. The AD7654 offers a parallel 16-bit word plus a serial port, while the AD7653 provides a parallel interface and a serial interface with its own timing specifications. Designers should confirm the interface mode, word length, and timing parameters against the specific device datasheet before reusing a digital interface design.
What are the analog input configurations of the AD7654ASTZ and AD7653ASTZRL?
The AD7654ASTZ provides two analog input channels that can be configured for simultaneous sampling, with input ranges selectable via the datasheet-defined configuration. The AD7653ASTZRL provides a single analog input channel with a defined input range per its datasheet. Because the channel count and input configuration differ, the external signal conditioning and multiplexing requirements are not interchangeable between the two parts.
Can the AD7653ASTZRL replace the AD7654ASTZ in an existing dual-channel design?
No. The AD7653ASTZRL is a single-channel ADC, so it cannot directly replace the dual-channel AD7654ASTZ in a design that requires two simultaneously sampled inputs. Replacing the AD7654 with the AD7653 would require adding external multiplexing or a second converter, and the pinout and interface differences must also be resolved. Any substitution should be validated against both datasheets and the target system requirements.
What are the package and operating temperature specifications for both parts?
Both the AD7654ASTZ and the AD7653ASTZRL are offered in a 48-lead LQFP package. The "ASTZ" suffix in both part numbers indicates the LQFP package and the industrial temperature range specified in the respective Analog Devices datasheets. Designers should confirm the exact temperature grade and package drawing from the official datasheet for each part before finalizing the PCB footprint and thermal design.