Part A
ADS1281IPW
Texas Instruments
- Lifecycle
- Active
- Stock
- 4383 Stückzahl
- Package
- TSSOP-24
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1281IPW and ADS1208IPWRG4 are not drop-in replacements for one another. The ADS1281IPW is a high-resolution 31-bit delta-sigma ADC with a serial SPI interface in a TSSOP-24 package, while the ADS1208IPWRG4 is a 16-bit delta-sigma modulator with a different output format and a TSSOP-16 footprint. The differing resolution, output interface, channel architecture, and package pinout require board-level redesign and firmware changes, so the two parts cannot be substituted without validation.
Different resolution
Different output interface
Different channel architecture
Different package footprint
Parts at a glance
Part B
ADS1208IPWRG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 4872 Stückzahl
- Package
- TSSOP-16
- Series
- Datenerfassung von ADCs-DACs für besonderen Zweck
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 | ADS1208IPWRG4 | 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 resolution than a 16-bit device, so they are not functionally interchangeable in high-precision applications. |
| Architecture | Delta-sigma (high-resolution) | Delta-sigma modulator | The ADS1281 is a complete high-resolution ADC, while the ADS1208 is a modulator-only device requiring external digital filtering, which fundamentally changes the system design and interface requirements. |
| Output Interface | SPI (serial) | Serial bit-stream modulator output | The output format dictates how the host processor receives data; a filtered SPI output versus a raw modulator bit-stream means different firmware and signal-processing paths are needed. |
| Number of Input Channels | 1 (single-ended/differential) | 1 (differential) | Channel configuration affects how many signals can be measured and the input wiring; differing input topologies impact direct board-level substitution. |
| Supply Voltage | 5 V analog, 3.3 V digital (dual supply) | 5 V (single supply) | Supply requirements determine power-rail compatibility; a dual-supply device cannot be dropped into a single-supply socket without redesign. |
| Package | TSSOP-24 | TSSOP-16 | Package footprint and pin count must match for physical board compatibility; different pin counts prevent direct drop-in replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range defines the environments in which the part can reliably operate; matching ranges indicate similar environmental robustness. |
| Typical Application Focus | Seismic and high-resolution energy exploration, precision instrumentation | Motor control, current sensing, isolated measurement | Target applications reveal the intended signal chain; a seismic-grade precision ADC and a motor-control modulator serve very different system roles and are not substitutes. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1281IPW | ADS1208IPWRG4 |
|---|---|---|
| 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 | - | Analog and Digital |
| Voltage - Supply | - | 2.7V ~ 5.5V, 4.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°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 ADS1208IPWRG4?
The ADS1281IPW is a single-channel, 31-bit delta-sigma analog-to-digital converter designed for high-resolution seismic and energy exploration applications, featuring a programmable gain amplifier and operating from a 5 V analog supply. The ADS1208IPWRG4 is a 16-bit, second-order delta-sigma modulator with an integrated driver for current measurement and isolated signal path applications, operating from a 5 V supply with a digital output interface. They differ fundamentally in resolution, architecture, and intended application.
Are the ADS1281IPW and ADS1208IPWRG4 pin-compatible or package-compatible?
No. The ADS1281IPW is supplied in a 24-pin TSSOP (PW) package, while the ADS1208IPWRG4 is supplied in a 16-pin TSSOP (PW) package. The pin counts and pin functions differ, so they are not drop-in replacements for each other.
What are the resolution and output data rate specifications for each device?
The ADS1281IPW provides 31-bit resolution with programmable output data rates from 250 SPS to 4 kSPS. The ADS1208IPWRG4 is a 16-bit modulator with an output data rate determined by the external clock and digital filter, typically operating with a clock input up to 20 MHz.
Do both devices support the same analog input configuration?
No. The ADS1281IPW features a differential analog input with a programmable gain amplifier (PGA) supporting gains of 1 to 64, suitable for direct sensor connection. The ADS1208IPWRG4 provides a differential input intended for current measurement through an external shunt resistor, with an integrated driver stage, and does not include a PGA.
What are the supply voltage requirements for the ADS1281IPW and ADS1208IPWRG4?
The ADS1281IPW operates from a 5 V analog supply (AVDD) and a 1.8 V to 3.3 V digital supply (DVDD). The ADS1208IPWRG4 operates from a 5 V analog supply and a 2.7 V to 5.5 V digital supply, with an integrated voltage reference option.
Which device is better suited for high-resolution seismic or energy exploration data acquisition?
The ADS1281IPW is specifically designed for high-resolution seismic and energy exploration applications, offering 31-bit resolution, low noise, and a PGA. The ADS1208IPWRG4, with 16-bit resolution and a modulator architecture, is intended for current measurement and isolated signal path applications rather than high-resolution seismic acquisition.
Can the ADS1208IPWRG4 be used as a direct substitute for the ADS1281IPW in an existing design?
No. The devices differ in resolution (16-bit vs. 31-bit), package (16-pin vs. 24-pin TSSOP), input architecture (modulator with driver vs. PGA-based ADC), and digital interface. A direct substitution is not possible without redesigning the signal chain, PCB layout, and digital filtering.