Part A
AD7655ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5580 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7655ASTZ and AD7653ASTZRL are both 16-bit successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a compatible supply and reference architecture, so the AD7655ASTZ can serve as a functional replacement candidate for the AD7653ASTZRL where dual simultaneous sampling is acceptable. However, the two devices differ in channel configuration and digital interface, so the replacement requires validation against the target design's input topology and timing requirements before adoption.
Channel Configuration
Validation required
Resolution and Architecture
High match
Digital Interface
Validation required
Package Type
High match
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 | AD7655ASTZ | AD7653ASTZRL | Why it matters |
|---|---|---|---|
| Number of ADC Input Channels | 4 (2 differential / 4 single-ended, multiplexed) | 1 (single-ended) | Determines how many signal sources can be digitized; the AD7655 supports multiplexed multi-channel acquisition while the AD7653 handles only one channel. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so dynamic range and LSB size are equivalent for a given input span. |
| Maximum Sampling Rate | 1 MSPS | 1 MSPS | Identical throughput allows either part to meet the same acquisition bandwidth requirements. |
| Input Configuration / Range | Pseudo-differential, 0 V to 5 V (with 2.5 V reference) | Single-ended, 0 V to 5 V (with 2.5 V reference) | Input topology affects signal conditioning and grounding; the AD7655 can accept differential or pseudo-differential signals while the AD7653 is single-ended only. |
| Interface Type | Parallel (byte/word) and Serial (SPI/QSPI/MICROWIRE/DSP) | Parallel (byte/word) and Serial (SPI/QSPI/MICROWIRE/DSP) | Both offer the same host interface options, simplifying drop-in compatibility with existing digital back-ends. |
| Supply Voltage | 5 V analog (AVDD), 5 V digital (DVDD), 3 V to 5 V VDRIVE | 5 V analog (AVDD), 5 V digital (DVDD), 3 V to 5 V VDRIVE | Matching supply rails means the same power design and level-shifting can be reused for either device. |
| Package | 48-lead LQFP | 48-lead LQFP | Identical package and pin count allow the same PCB footprint, though pin functions must be verified for direct substitution. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range ensures equivalent environmental robustness for both parts. |
| Power Consumption (Typical) | Approximately 120 mW at 1 MSPS | Approximately 120 mW at 1 MSPS | Comparable power draw means thermal and supply budgeting remain essentially unchanged between the two devices. |
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Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7655ASTZ | AD7653ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 1M | 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 AD7655ASTZ and the AD7653ASTZRL?
The AD7655ASTZ is a dual-channel, 16-bit, 1 MSPS successive-approximation ADC with two simultaneous-sampling SAR cores, while the AD7653ASTZRL is a single-channel, 16-bit, 1 MSPS SAR ADC. The AD7655 provides two independent ADC channels in a 48-lead LQFP package, whereas the AD7653 offers one channel in a 48-lead LQFP package. Both are pin-compatible in package footprint but differ in channel count and internal architecture.
Are the AD7655ASTZ and AD7653ASTZRL pin-to-pin compatible?
No. Although both devices are offered in a 48-lead LQFP package, their pin functions differ because the AD7655ASTZ integrates two ADC channels with separate analog inputs and conversion control, while the AD7653ASTZRL is a single-channel device. A direct PCB drop-in replacement is not possible without verifying pin assignments against the respective datasheets.
Do both parts support the same sampling rate and resolution?
Yes. Both the AD7655ASTZ and AD7653ASTZRL are 16-bit SAR ADCs with a maximum throughput of 1 MSPS. The AD7655 achieves this with two simultaneous-sampling channels, while the AD7653 achieves it with a single channel.
What analog input configurations do these ADCs support?
The AD7655ASTZ provides two independent analog input channels that can be configured for either single-ended or differential operation, with simultaneous sampling on both channels. The AD7653ASTZRL provides a single analog input channel configurable for either single-ended or differential input. Both devices support a 0 V to 5 V input range in unipolar mode and a ±10 V range in bipolar mode, depending on configuration.
Do the AD7655ASTZ and AD7653ASTZRL use the same digital interface?
Both devices provide a parallel digital interface for connection to a host processor or DSP, and both support a serial interface option via the SER/PAR pin. The AD7655ASTZ includes two separate conversion result registers for its dual channels, while the AD7653ASTZRL has a single result register. Interface timing and register maps should be verified against each datasheet before reuse of firmware or FPGA logic.
Can the AD7653ASTZRL be used as a replacement for the AD7655ASTZ in an existing design?
Not directly. The AD7653ASTZRL provides only one ADC channel, so any design relying on the AD7655ASTZ's dual simultaneous-sampling capability would lose one channel. Pin functions, register maps, and conversion control also differ. A replacement requires schematic, layout, and firmware changes validated against the AD7653 datasheet.
What are the power supply requirements for these devices?
Both the AD7655ASTZ and AD7653ASTZRL operate from a 5 V analog supply (AVDD) and a 5 V digital supply (DVDD), with a separate interface supply (OVDD) that can range from 2.7 V to 5.25 V to match the host logic level. Both devices also require a reference voltage, typically 2.5 V, applied to the REF pin. Exact supply tolerances and decoupling requirements should be confirmed in the respective datasheets.
Are both parts available in the same operating temperature range?
Yes. Both the AD7655ASTZ and AD7653ASTZRL are specified for the industrial temperature range of −40°C to +85°C, as indicated by the "A" grade designation in their part numbers. The "STZ" and "STZRL" suffixes denote the 48-lead LQFP package and tape-and-reel packaging option, respectively.