Part A
ADS1278HPAP
Texas Instruments
- Lifecycle
- Active
- Stock
- 1933 PCS
- Package
- HTQFP-64
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1258IPHPREP and ADS1278HPAP are not drop-in replacements for one another. Although both are multi-channel delta-sigma ADCs in the same HTQFP-64 package family, they differ fundamentally in channel count, output data interface, and conversion architecture, so a direct board-level swap is not feasible without redesign and validation.
Different channel count
Different output interface
Different conversion architecture
Different footprint
Parts at a glance
Part B
ADS1258IPHPREP
Texas Instruments
- Lifecycle
- Active
- Stock
- 4609 PCS
- Package
- HTQFP-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 | ADS1258IPHPREP | ADS1278HPAP | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma ADCs, so resolution alone does not differentiate them for substitutability. |
| Number of input channels | 16 (single-ended) / 8 (differential) | 8 (differential) | Channel count determines how many signals can be digitized; the ADS1258 offers more single-ended inputs via multiplexing. |
| Maximum data rate (SPS) | 125 kSPS | 144 kSPS | Data rate affects achievable sampling bandwidth and throughput for the target application. |
| Architecture | Delta-sigma with multiplexer (multiplexed) | Delta-sigma, simultaneous-sampling | Simultaneous sampling preserves phase relationships across channels, while multiplexed designs trade that for channel count. |
| Interface | SPI | SPI | Both use SPI, so host-side digital interfacing is compatible for drop-in consideration. |
| Supply voltage (analog) | 5 V (analog) | 5 V (analog) | Matching analog supply simplifies power-rail reuse when evaluating substitution. |
| Package | 48-pin HTQFP (PowerPAD) | 64-pin HTQFP (PowerPAD) | Different package footprint and pin count prevent direct board-level drop-in replacement. |
| Operating temperature range | -40°C to +125°C | -40°C to +125°C | Both are rated for extended temperature, suitable for harsh-environment applications. |
| Input type | Single-ended / differential (multiplexed) | Differential (simultaneous) | Input configuration affects sensor interfacing flexibility and signal conditioning requirements. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1278HPAP | ADS1258IPHPREP |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 144k | 125k |
| Number of Inputs | 8 | 8, 16 |
| Input Type | Differential | Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | ADC | MUX-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 1.65V ~ 1.95V | 2.7V ~ 5.25V |
| Operating Temperature | -55°C ~ 175°C | -40°C ~ 105°C |
Frequently asked questions
What are the primary functional differences between the ADS1258IPHPREP and the ADS1278HPAP?
The ADS1258IPHPREP is a 16-channel, 24-bit delta-sigma ADC with an integrated multiplexer and a maximum data rate of 125 kSPS. The ADS1278HPAP is an octal, simultaneous-sampling, 24-bit delta-sigma ADC with a maximum data rate of 144 kSPS per channel. The ADS1258IPHPREP is designed for multiplexed multi-channel scanning, while the ADS1278HPAP is designed for simultaneous sampling of eight independent channels.
Do the ADS1258IPHPREP and ADS1278HPAP use the same package and pinout?
No. The ADS1258IPHPREP is supplied in a 48-pin HTQFP (PHP) package, while the ADS1278HPAP is supplied in a 64-pin HTQFP (PAP) package. The pin counts and pin functions differ, so the two devices are not pin-compatible and cannot be interchanged on the same PCB land pattern without redesign.
How do the input architectures of the ADS1258IPHPREP and ADS1278HPAP differ?
The ADS1258IPHPREP provides a single-ended or differential input multiplexer that routes one of 16 single-ended or 8 differential input channels to a single ADC. The ADS1278HPAP provides eight independent differential input channels, each with its own dedicated delta-sigma modulator and simultaneous-sampling capability, which preserves channel-to-channel phase relationships.
What are the maximum data rates of the ADS1258IPHPREP and ADS1278HPAP?
The ADS1258IPHPREP supports a maximum data rate of 125 kSPS. The ADS1278HPAP supports a maximum data rate of 144 kSPS per channel in high-speed mode. Both devices are 24-bit delta-sigma converters, but the ADS1278HPAP offers higher per-channel throughput with simultaneous sampling.
Are the ADS1258IPHPREP and ADS1278HPAP specified for the same operating temperature range?
Both devices are specified over the industrial temperature range of -40°C to +125°C, consistent with their HTQFP package and high-temperature "H" grade designation. Designers should still confirm the exact temperature specification in the respective manufacturer datasheets for the specific grade ordered.
Which device is better suited for simultaneous multi-channel acquisition?
The ADS1278HPAP is better suited for simultaneous multi-channel acquisition because it contains eight independent delta-sigma modulators that sample all channels at the same instant. The ADS1258IPHPREP uses a multiplexed front end, so its channels are sampled sequentially rather than simultaneously, which introduces channel-to-channel timing skew.
Can the ADS1258IPHPREP and ADS1278HPAP operate from the same analog supply voltage?
Both devices support a 5 V analog supply (AVDD) as their nominal analog supply, with separate digital supplies for the interface. However, the exact supply rail requirements, including the digital I/O supply range, should be verified against the respective manufacturer datasheets before designing a common power tree.
What serial interface do the ADS1258IPHPREP and ADS1278HPAP provide?
Both devices provide an SPI-compatible serial interface for configuration and data readout. The ADS1258IPHPREP uses a multiplexed conversion result readout with a dedicated DRDY signal, while the ADS1278HPAP provides per-channel data output with framing suitable for simultaneous-sampling systems. Interface timing and register maps differ between the two devices.