Part A
AD7656BSTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3438 Stückzahl
- Package
- LQFP-64
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The AD7656BSTZ and AD7653ASTZRL 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 AD7653ASTZRL is a single-channel bipolar ADC in a 48-lead LQFP. They differ in channel count, package footprint, and digital interface, 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
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7144 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit 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 | AD7656BSTZ | 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 substituted by a single-channel device in multi-channel systems. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so precision class is equivalent, but channel count and architecture still differ. |
| Sampling Rate | 250 kSPS | 1 MSPS | Maximum throughput affects the ability to capture fast-changing signals; the single-channel part is significantly faster per channel. |
| Input Type | Bipolar (true bipolar) | Pseudo-differential / unipolar | Input configuration must match the signal conditioning; bipolar inputs accept negative voltages while unipolar inputs do not. |
| Interface | Parallel / Serial (SPI) | Serial (SPI) | Interface compatibility determines whether the part can drop into an existing digital bus without redesign. |
| Package | 64-lead LQFP | 48-lead LQFP | Footprint and pin count must match the PCB layout; different packages require board redesign. |
| Supply Voltage | 5 V analog / 5 V digital (with separate supplies) | 5 V analog / 5 V digital | Supply rails must be compatible with the surrounding system; both operate on 5 V but the multi-channel part supports separate analog/digital rails. |
| Power Consumption | Higher (multi-channel) | Lower (single-channel) | Power budget and thermal design depend on the number of active channels and conversion rate. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7656BSTZ | 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 ~ 85°C | -40°C ~ 85°C |
| Features | Simultaneous Sampling, True Bipolar | - |
Frequently asked questions
What are the primary differences between the AD7656BSTZ and the AD7653ASTZRL?
The AD7656BSTZ is a 16-bit, 6-channel simultaneous-sampling SAR ADC offering 250 kSPS per channel, while the AD7653ASTZRL is a 16-bit, single-channel SAR ADC offering 1 MSPS. The AD7656BSTZ is housed in a 64-lead LQFP package, whereas the AD7653ASTZRL is supplied in a 48-lead LQFP. The AD7653ASTZRL is specified for operation from a single 5 V supply, while the AD7656BSTZ requires separate analog and digital supplies (typically ±5 V analog and 5 V digital).
Can the AD7656BSTZ and AD7653ASTZRL be used interchangeably in an existing design?
No. The two devices differ in channel count (6 vs. 1), throughput (250 kSPS vs. 1 MSPS), package footprint (64-lead vs. 48-lead LQFP), and supply architecture. Pin functions and PCB land patterns are not compatible, so a direct drop-in substitution is not possible without a board redesign and firmware changes.
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 AD7653ASTZRL offers a throughput of 1 MSPS on a single channel.
How do the analog input configurations differ between the two parts?
The AD7656BSTZ provides six independent analog input channels that can be configured as six single-ended inputs or three true differential pairs, with simultaneous sampling on all channels. The AD7653ASTZRL provides a single pseudo-differential analog input channel with a defined input voltage range set by the reference and configuration.
What are the supply voltage requirements for each device?
The AD7656BSTZ operates from separate analog and digital supplies, typically ±5 V for the analog section and 5 V for the digital interface. The AD7653ASTZRL operates from a single 5 V supply for both analog and digital functions.
Which device is better suited for multi-channel simultaneous-sampling applications?
The AD7656BSTZ is designed for multi-channel simultaneous-sampling applications, as it integrates six ADCs that sample all channels at the same instant, preserving phase relationships between signals. The AD7653ASTZRL, being a single-channel device, would require external multiplexing and multiple devices to achieve comparable multi-channel simultaneous sampling.
Which device is better suited for high-speed single-channel acquisition?
The AD7653ASTZRL is better suited for high-speed single-channel acquisition because it provides 1 MSPS throughput on a single channel, four times the per-channel rate of the AD7656BSTZ. The AD7656BSTZ is optimized for multi-channel simultaneity rather than maximum single-channel speed.
Do both devices support a parallel digital interface?
Yes. Both the AD7656BSTZ and the AD7653ASTZRL provide a parallel digital interface for connection to a host processor or DSP. The AD7656BSTZ also supports a high-speed serial interface option, while the AD7653ASTZRL provides a parallel interface for reading conversion results.