Part A
ADS8555SPMR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2733 PCS
- Package
- LQFP-64
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS8556IPMR and ADS8555SPMR are functionally comparable 16-bit, 6-channel simultaneous-sampling SAR ADCs sharing the same TQFP-64 footprint and pinout, making the ADS8555SPMR a viable functional replacement candidate for the ADS8556IPMR in most applications. Designers should validate the reduced maximum sampling rate and the narrower industrial temperature range against their specific system requirements before qualifying the substitution.
Maximum Sampling Rate
Validation required
Package Type
High match
Resolution and Channel Count
High match
Operating Temperature Range
Validation required
Parts at a glance
Part B
ADS8556IPMR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2848 PCS
- Package
- LQFP-64
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS8556IPMR | ADS8555SPMR | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit devices, so nominal resolution is identical and not a differentiator for substitutability. |
| Number of ADC channels | 6 | 6 | Channel count determines how many analog inputs can be sampled; both provide six simultaneous-sampling channels. |
| Sampling rate (max) | 630 kSPS | 630 kSPS | Maximum throughput affects achievable signal bandwidth and system timing; identical rates mean equivalent speed capability. |
| Input type | Single-ended / pseudo-differential | Single-ended / pseudo-differential | Input configuration must match the sensor or signal source topology for correct measurement. |
| Supply voltage (analog) | 5 V | 5 V | Analog supply range must be compatible with the board's power rails and input signal swing. |
| Interface | Parallel / Serial (SPI) | Parallel / Serial (SPI) | The digital interface must match the host controller's available bus to allow drop-in replacement. |
| Operating temperature range | -40 °C to +125 °C | -40 °C to +125 °C | Temperature range determines suitability for industrial and harsh-environment applications. |
| Package | LQFP-64 | LQFP-64 | Package and pinout must match for physical board compatibility and reflow assembly. |
| Pin count | 64 | 64 | Pin count confirms footprint compatibility between the two devices. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS8555SPMR | ADS8556IPMR |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 630k | 630k |
| Number of Inputs | 6 | 6 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, Parallel | SPI, Parallel |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 2.7V ~ 3.6V, 5V | 2.7V ~ 3.6V, 5V |
| Features | Simultaneous Sampling | Simultaneous Sampling |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
Frequently asked questions
What are the key differences between the ADS8556IPMR and ADS8555SPMR?
The ADS8556IPMR is a 16-bit, 6-channel simultaneous-sampling SAR ADC, while the ADS8555SPMR is a 16-bit, 6-channel simultaneous-sampling SAR ADC with an integrated programmable gain amplifier (PGA) front end. The ADS8555SPMR supports software-programmable input ranges via its PGA, whereas the ADS8556IPMR provides fixed analog input ranges. Both are pin-compatible 64-pin LQFP devices from Texas Instruments.
Are the ADS8556IPMR and ADS8555SPMR pin-to-pin compatible?
Yes. Both devices are offered in the same 64-pin LQFP (PM) package with the same pinout, allowing a common PCB footprint. However, because the ADS8555SPMR includes a PGA front end, the analog input signal conditioning requirements differ, so the surrounding circuitry must be validated for the selected device.
What is the maximum sampling rate of these ADCs?
Both the ADS8556IPMR and ADS8555SPMR support a maximum throughput of 630 kSPS per channel in parallel interface mode. The conversion rate depends on the selected interface mode and the external clock/reference configuration as specified in the respective datasheets.
Do both devices support simultaneous sampling of all six channels?
Yes. Both the ADS8556IPMR and ADS8555SPMR feature six independent sample-and-hold circuits that sample all six analog inputs simultaneously, which preserves phase relationships between channels in motor control, power monitoring, and multi-axis measurement applications.
What analog input ranges does the ADS8555SPMR support compared with the ADS8556IPMR?
The ADS8555SPMR integrates a PGA that provides software-selectable input ranges, including ±10 V, ±5 V, and ±2.5 V differential ranges. The ADS8556IPMR does not include a PGA and uses fixed analog input ranges as defined in its datasheet. Designers should confirm the exact range options against the official TI datasheet for each device.
What supply voltages and reference options do these ADCs require?
Both devices operate from an analog supply (AVDD) of 5 V and a digital supply (DVDD) of 2.7 V to 5.5 V, with an additional interface supply as specified by TI. Both support internal or external voltage reference options. Exact supply and reference specifications should be verified in the respective ADS8556 and ADS8555 datasheets.
What interface modes are available on the ADS8556IPMR and ADS8555SPMR?
Both devices support parallel, serial, and daisy-chain interface modes for connection to host processors, DSPs, and FPGAs. The interface mode is selected via dedicated configuration pins, and timing parameters for each mode are documented in the TI datasheets.
Can the ADS8556IPMR be used as a drop-in replacement for the ADS8555SPMR in an existing design?
Not without validation. Although the devices share the same package and pinout, the ADS8555SPMR's integrated PGA changes the analog input structure and configuration requirements. A design built for the ADS8555SPMR must be re-evaluated for input range settings, external signal conditioning, and configuration register behavior before substituting the ADS8556IPMR, and vice versa.