Part A
ADS1281IPW
德州儀器
- Lifecycle
- Active
- Stock
- 4383 件
- Package
- TSSOP-24
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The ADS1281IPW and ADS1222IPWRG4 are not drop-in replacements for one another. The ADS1281IPW is a high-resolution 31-bit delta-sigma ADC with a single channel and SPI interface in a TSSOP-28 package, while the ADS1222IPWRG4 is a 24-bit delta-sigma ADC with two differential channels and a two-wire serial interface in a TSSOP-16 package. The differences in resolution, channel count, interface architecture, and package footprint require full circuit redesign and validation before any substitution can be considered.
Different resolution
Different channel count
Different interface type
Different package footprint
Parts at a glance
Part B
ADS1222IPWRG4
德州儀器
- Lifecycle
- Active
- Stock
- 4722 件
- Package
- TSSOP-14
- Series
- 資料獲取-模數轉換器（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 | ADS1281IPW | ADS1222IPWRG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 31 | 24 | Higher resolution provides finer measurement granularity; a 31-bit ADC can resolve much smaller signal changes than a 24-bit device. |
| Number of input channels | 1 (differential) | 2 (differential) | Channel count determines how many independent signals can be measured without external multiplexing. |
| Architecture | Delta-Sigma | Delta-Sigma | Both use delta-sigma conversion, suited to high-resolution low-frequency measurements, but their internal designs target different speed/resolution tradeoffs. |
| Maximum sample rate | 4 kSPS | 2 kSPS | Sample rate bounds the bandwidth of signals that can be captured; higher rates support faster-changing inputs. |
| Supply voltage (analog) | 5 V (analog), 1.8 V–3.3 V (digital) | 2.7 V–5.5 V | Supply requirements affect power-rail design and compatibility with the surrounding system. |
| Interface | SPI | SPI | Both use SPI, but timing and register maps differ, so firmware must be adapted when substituting. |
| Package | TSSOP-24 | TSSOP-16 | Different pin counts and footprints require PCB layout changes; they are not drop-in replacements. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Both cover the industrial temperature range, so environmental suitability is comparable. |
| Input type | Differential | Differential | Differential inputs improve common-mode noise rejection, important for precision sensor measurements. |
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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 | ADS1281IPW | ADS1222IPWRG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | 31 | 24 |
| Sampling Rate(Per Second) | 4k | 240 |
| Number of Inputs | 1 | 2 |
| Input Type | Differential, Single Ended | 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 | 2.7V ~ 5.5V |
| Voltage - Supply, Digital | 1.65V ~ 3.6V | 2.7V ~ 5.5V |
| Features | - | Temperature Sensor |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the primary differences between the ADS1281IPW and ADS1222IPWRG4?
The ADS1281IPW is a single-channel, 31-bit delta-sigma ADC with a maximum data rate of 4 kSPS, housed in a 24-pin TSSOP package, and specified for operation from -40°C to +85°C. The ADS1222IPWRG4 is a 24-bit, 4-channel delta-sigma ADC with a maximum data rate of 105 SPS, supplied in a 20-pin TSSOP package, and also rated for -40°C to +85°C. The ADS1281IPW targets high-resolution seismic and energy exploration applications, while the ADS1222IPWRG4 targets low-power sensor measurement applications.
Are the ADS1281IPW and ADS1222IPWRG4 pin-compatible?
No. The ADS1281IPW uses a 24-pin TSSOP package, while the ADS1222IPWRG4 uses a 20-pin TSSOP package. The different pin counts and pin functions prevent direct PCB footprint compatibility, so a board redesign is required to interchange them.
How do the resolution and data rate specifications compare?
The ADS1281IPW provides 31-bit resolution with a maximum data rate of 4 kSPS. The ADS1222IPWRG4 provides 24-bit resolution with a maximum data rate of 105 SPS. The ADS1281IPW therefore offers higher resolution and a significantly faster maximum output rate, while the ADS1222IPWRG4 is intended for lower-speed, multi-channel measurement.
How many input channels does each device support?
The ADS1281IPW is a single-channel ADC. The ADS1222IPWRG4 provides four input channels. Designs requiring multiple sensor inputs may favor the ADS1222IPWRG4, while single-channel high-resolution applications may favor the ADS1281IPW.
What are the supply voltage requirements for each part?
The ADS1281IPW operates from an analog supply of 5 V (4.75 V to 5.25 V) and a digital supply of 3.3 V (3.0 V to 3.6 V). The ADS1222IPWRG4 operates from a single supply of 2.7 V to 5.5 V. The ADS1222IPWRG4 therefore supports lower-voltage single-supply systems, while the ADS1281IPW requires a dual-supply arrangement.
Do both devices support the same digital interface?
No. The ADS1281IPW provides a serial peripheral interface (SPI)-compatible interface. The ADS1222IPWRG4 provides a two-wire serial interface. Firmware and host interface logic must be adapted when migrating between these devices.
What are the typical application targets for each device?
The ADS1281IPW is typically used in seismic data acquisition, energy exploration, and high-resolution industrial measurement systems. The ADS1222IPWRG4 is typically used in portable instrumentation, temperature and pressure sensing, and low-power multi-channel sensor systems.
Can the ADS1222IPWRG4 be used as a drop-in replacement for the ADS1281IPW?
No. Differences in package pin count, supply voltage requirements, resolution, data rate, channel count, and digital interface prevent a drop-in replacement. Any substitution requires schematic, layout, and firmware changes validated against the respective manufacturer datasheets.