Part A
ADS1281IPW
Texas Instruments
- Lifecycle
- Active
- Stock
- 4383 PCS
- Package
- TSSOP-24
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1281IPW and ADS1203IPWRG4 are not functionally interchangeable. The ADS1281IPW is a high-resolution 31-bit delta-sigma ADC with an SPI-compatible serial interface, while the ADS1203IPWRG4 is a 16-bit isolated delta-sigma modulator with a single-bit Manchester-encoded output. They differ in resolution, output interface, isolation, and package, so the ADS1203IPWRG4 cannot serve as a direct substitute for the ADS1281IPW in existing designs.
Different output interface
Different resolution
Different isolation
Different package
Parts at a glance
Part B
ADS1203IPWRG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 4572 PCS
- Package
- TSSOP-8
- Series
- Acquisição de dados - ADCs-DACs - Objetivo Especial
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS1281IPW | ADS1203IPWRG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 31 | 16 | Resolution determines the smallest signal change the ADC can distinguish; a 31-bit delta-sigma converter offers far finer measurement granularity than a 16-bit device. |
| Architecture | Delta-Sigma (2nd order) | Delta-Sigma (2nd order) | Both use delta-sigma modulation, but the ADS1281 is a high-resolution measurement ADC while the ADS1203 is a modulator-only device intended for isolated current sensing. |
| Output Interface | SPI (serial) | Digital modulator bitstream (1-bit) | The output format dictates how the host or FPGA must interface with the device; a bitstream modulator requires external digital filtering, unlike a direct SPI data output. |
| Input Type | Differential | Differential | Differential inputs reject common-mode noise, which is critical for precision measurement in noisy industrial environments. |
| Data Rate / Sample Rate | Up to 4 kSPS | Up to 40 kSPS (modulator clock dependent) | Sample rate sets the maximum signal bandwidth and update rate; the ADS1203 supports higher modulator rates suited to motor and current-loop control. |
| Supply Voltage | 5 V (analog), 3.3 V (digital) | 5 V (analog), 3.3 V (digital) | Supply requirements determine power-rail compatibility and whether level shifting is needed in the target system. |
| Package | TSSOP-24 | TSSOP-16 | Package footprint and pin count affect PCB layout and whether the parts are drop-in compatible on an existing board. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range confirms suitability for industrial environments and matches the environmental rating of the end application. |
| Typical Application | Seismic and energy exploration, precision instrumentation | Motor control, isolated current sensing, power measurement | Intended application indicates the design context; the two parts target different measurement domains and are generally not functionally substitutable. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1281IPW | ADS1203IPWRG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Obsolete |
| Type | - | Modulator |
| Number of Channels | - | 1 |
| Resolution(Bits) | - | 16 b |
| Sampling Rate(Per Second) | 4k | 40k |
| Data Interface | SPI | Serial |
| Voltage Supply Source | - | Single Supply |
| Voltage - Supply | - | 4.75V ~ 5.25V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | - | Surface Mount |
| Number of Bits | 31 | - |
| Number of Inputs | 1 | - |
| Input Type | Differential, Single Ended | - |
| Configuration | ADC | - |
| Number of A/D Converters | 1 | - |
| Architecture | Sigma-Delta | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 1.65V ~ 3.6V | - |
Frequently asked questions
What are the primary functional differences between the ADS1281IPW and ADS1203IPWRG4?
The ADS1281IPW is a high-resolution, 31-bit delta-sigma analog-to-digital converter (ADC) designed primarily for seismic and energy exploration applications, featuring a programmable gain amplifier (PGA) and operating from a single 5 V analog supply. The ADS1203IPWRG4 is a 16-bit, second-order delta-sigma modulator designed for isolated current sensing and industrial motor control, outputting a 1-bit data stream for external digital filtering. They differ fundamentally in resolution, output format, and target application.
Are the ADS1281IPW and ADS1203IPWRG4 pin-to-pin or package compatible?
No. The ADS1281IPW is supplied in a 28-pin TSSOP (PW) package, while the ADS1203IPWRG4 is supplied in a 16-pin TSSOP (PW) package. The pin counts, pin functions, and PCB land patterns differ, so they are not drop-in replacements for one another.
What are the specified resolution and data output formats of each device?
The ADS1281IPW provides up to 31-bit resolution with a serial peripheral interface (SPI) output of fully filtered digital codes. The ADS1203IPWRG4 provides 16-bit resolution via a 1-bit delta-sigma modulated output stream that requires an external digital filter (e.g., in an FPGA or microcontroller) to reconstruct the digital word.
Can the ADS1203IPWRG4 be used as a direct substitute for the ADS1281IPW in seismic or precision measurement designs?
No. The ADS1203IPWRG4 offers 16-bit resolution and a 1-bit modulator output, whereas the ADS1281IPW provides up to 31-bit resolution with an integrated digital filter and PGA. Substitution would require redesign of the digital filtering, gain stage, and system resolution budget, and is not supported as a direct replacement.
What are the typical supply voltage requirements for each part?
The ADS1281IPW operates from a 5 V analog supply (AVDD) with a separate digital supply (DVDD) in the 1.8 V to 3.3 V range. The ADS1203IPWRG4 operates from a single 5 V supply (AVDD) with a digital supply (DVDD) in the 2.7 V to 5.5 V range. Designers should confirm exact limits in the respective manufacturer datasheets.
Which device is better suited for isolated current-sense applications?
The ADS1203IPWRG4 is specifically intended for isolated current sensing and industrial motor control, as its 1-bit modulator output can be passed through a digital isolator to an external filter. The ADS1281IPW is a precision, fully filtered ADC intended for seismic and energy exploration, not for isolated current-sense signal chains.
Do both devices support the same digital interface for system integration?
No. The ADS1281IPW uses an SPI-compatible serial interface to output filtered conversion results. The ADS1203IPWRG4 outputs a 1-bit delta-sigma modulated data stream (MDAT) with a clock (MCLK), requiring an external digital filter. The interface architectures and system integration requirements are therefore different.