Part A
AD7656YSTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7772 PCS
- Package
- LQFP-64
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The AD7656YSTZ and AD7653ASTZRL are not drop-in replacements for one another. The AD7656YSTZ is a six-channel simultaneous-sampling bipolar ADC in a 64-lead LQFP, while the AD7653ASTZRL is a single-channel bipolar ADC in a 48-lead LQFP. They differ in channel count, package footprint, and digital interface configuration, so a direct board-level substitution is not possible without redesign.
Different channel count
Different package footprint
Different digital interface
Different conversion architecture
Parts at a glance
Part B
AD7653ASTZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7144 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - 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 | AD7656YSTZ | AD7653ASTZRL | 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 replaced by a single-channel device in multi-channel acquisition systems. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so precision and dynamic range are equivalent, which is favorable for substitutability. |
| Sampling Rate (max) | 250 kSPS | 1 MSPS | The maximum throughput affects the highest signal frequency that can be captured; the AD7653 supports faster sampling, which may be required for higher-bandwidth signals. |
| Architecture | SAR | SAR | Both use successive-approximation register architecture, giving similar latency and no pipeline delay, which supports functional equivalence. |
| Input Type | Single-ended | Single-ended | Matching input configuration ensures the same signal conditioning and front-end circuitry can be reused. |
| Supply Voltage (Analog) | 5 V | 5 V | Identical analog supply requirements simplify power design and allow the same voltage regulation to be shared. |
| Interface | Parallel / Serial (SPI) | Parallel / Serial (SPI) | Compatible digital interfaces allow the same host controller and firmware communication path to be used. |
| Package | LQFP-64 | LQFP-48 | Different package footprints and pin counts require PCB redesign, so the parts are not drop-in replacements. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +85 °C | The wider temperature range of the AD7656 suits harsher environments; the AD7653 is limited to standard industrial conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7656YSTZ | AD7653ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | iCMOS® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 250k | 1M |
| Number of Inputs | 6 | 1 |
| Input Type | Single Ended | Pseudo-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 | 6 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Features | Simultaneous Sampling, True Bipolar | - |
Frequently asked questions
What are the key architectural differences between the AD7656YSTZ and the AD7653ASTZRL?
The AD7656YSTZ is a 16-bit, 6-channel, simultaneous-sampling successive approximation register (SAR) analog-to-digital converter, while the AD7653ASTZRL is a 16-bit, single-channel, pseudo-differential SAR ADC. The AD7656YSTZ integrates six ADCs that sample simultaneously, making it suited for multiphase motor control and power monitoring, whereas the AD7653ASTZRL provides one channel with a higher throughput rate of up to 1 MSPS.
How do the sampling rates of the AD7656YSTZ and AD7653ASTZRL compare?
The AD7656YSTZ offers a maximum throughput of 250 kSPS per channel across its six simultaneous-sampling channels. The AD7653ASTZRL provides a maximum throughput of 1 MSPS on its single channel. The AD7653ASTZRL therefore delivers four times the per-channel conversion rate of the AD7656YSTZ.
Do the AD7656YSTZ and AD7653ASTZRL use the same package and pinout?
No. The AD7656YSTZ is supplied in a 64-lead LQFP package, while the AD7653ASTZRL is supplied in a 48-lead LQFP package. The two devices have different pin counts and pin functions, so they are not pin-compatible and cannot be interchanged on the same PCB land pattern without redesign.
What analog input configurations do the AD7656YSTZ and AD7653ASTZRL support?
The AD7656YSTZ provides six single-ended analog input channels that can also be configured as three true differential pairs, with a selectable input range of ±10 V or ±5 V. The AD7653ASTZRL provides a single pseudo-differential input with a selectable range of ±10 V, ±5 V, or 0 V to 10 V. The AD7656YSTZ is therefore better suited to multi-channel bipolar signal acquisition, while the AD7653ASTZRL targets single-channel high-speed acquisition.
What digital interfaces do the AD7656YSTZ and AD7653ASTZRL provide?
Both devices provide a parallel interface and a serial interface for connection to host processors or FPGAs. The AD7656YSTZ supports a high-speed parallel interface and a serial interface, and it includes a daisy-chain capability for cascading multiple converters. The AD7653ASTZRL supports a parallel interface and an SPI-compatible serial interface. The exact timing and word-length requirements should be confirmed against the respective manufacturer datasheets.
Can the AD7656YSTZ and AD7653ASTZRL operate from the same supply voltages?
Both devices use a 5 V analog supply and a separate digital supply that supports interfacing to 3 V or 5 V logic. The AD7656YSTZ additionally requires external reference and interface supply considerations for its six channels, while the AD7653ASTZRL integrates an on-chip reference. Designers should verify the exact supply and reference requirements in the manufacturer datasheets before finalizing a power architecture.
Which device is more appropriate for simultaneous multi-channel acquisition?
The AD7656YSTZ is the appropriate choice for simultaneous multi-channel acquisition because its six SAR converters sample all channels at the same instant, preserving phase relationships between signals. The AD7653ASTZRL, with a single channel, cannot perform simultaneous sampling across multiple inputs and would require external multiplexing and multiple devices to achieve comparable multi-channel synchronization.
Are the AD7656YSTZ and AD7653ASTZRL drop-in replacements for each other?
No. The two devices differ in channel count, throughput, package size, pinout, and input configuration. They are not drop-in replacements, and substituting one for the other requires a PCB redesign and revalidation of the analog front end, timing, and firmware against the manufacturer datasheets.