Part A
ADS1256IDBT
Texas Instruments
- Lifecycle
- Active
- Stock
- 4833 PCS
- Package
- SSOP-28
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1220IPWR and ADS1256IDBT are both 24-bit delta-sigma ADCs, but they differ fundamentally in resolution architecture, channel count, interface protocol, and package footprint. The ADS1256IDBT offers higher effective resolution and more input channels, while the ADS1220IPWR provides a simpler SPI interface in a smaller package. These differences in core specifications and pinout mean the two devices are not functionally interchangeable without redesign of the surrounding circuitry, firmware, and PCB layout.
Different channel count
Different interface protocol
Different package footprint
Different data rate capability
Parts at a glance
Part B
ADS1220IPWR
Texas Instruments
- Lifecycle
- Active
- Stock
- 6260 PCS
- Package
- TSSOP-16
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (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 | ADS1220IPWR | ADS1256IDBT | 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 | 4 (2 differential / 4 single-ended) | 8 (4 differential / 8 single-ended) | Channel count determines how many sensors can be multiplexed; the ADS1256 supports twice the input count. |
| Maximum sample rate (SPS) | 2000 | 30000 | Higher sample rate enables faster signal acquisition and wider bandwidth; the ADS1256 is roughly 15x faster. |
| PGA gain range | 1 to 128 | 1 to 64 | PGA gain sets the smallest resolvable input signal; the ADS1220 offers one extra gain step for low-level signals. |
| Interface | SPI | SPI | Both use SPI, so the host microcontroller interface is compatible between the two parts. |
| Supply voltage (analog) | 2.3 V to 5.5 V | 5 V (4.75 V to 5.25 V) | The ADS1220 supports low-voltage and battery-powered rails, while the ADS1256 requires a regulated 5 V analog supply. |
| Package | TSSOP-16 | SSOP-28 | Different footprints and pin counts mean the two parts are not drop-in PCB replacements. |
| Internal oscillator | Yes | No (external crystal required) | An internal oscillator simplifies design and saves board space; the ADS1256 needs an external clock source. |
| Operating temperature range | -40 °C to +125 °C | -40 °C to +85 °C | The wider temperature range of the ADS1220 suits harsher environments and industrial applications. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1256IDBT | ADS1220IPWR |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 30k | 2k |
| Number of Inputs | 4, 8 | 2, 4 |
| Input Type | Differential, Single Ended | Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | MUX-PGA-ADC | MUX-PGA-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External, Internal, Supply |
| Voltage - Supply, Analog | 5V | 2.3V ~ 5.5V, ±2.5 |
| Voltage - Supply, Digital | 1.8V ~ 3.6V | 2.3V ~ 5.5V |
| Features | PGA | PGA, Temperature Sensor |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
Frequently asked questions
What are the primary differences between the ADS1220IPWR and ADS1256IDBT?
The ADS1220IPWR is a 24-bit, 4-channel delta-sigma ADC with an integrated PGA, offering data rates up to 2 kSPS and housed in a TSSOP-16 package. The ADS1256IDBT is a 24-bit, 8-channel delta-sigma ADC with a PGA, supporting data rates up to 30 kSPS and packaged in a TSSOP-28. The ADS1256 provides more input channels and higher throughput, while the ADS1220 offers a smaller footprint and lower channel count.
Are the ADS1220IPWR and ADS1256IDBT pin-compatible?
No. The ADS1220IPWR uses a 16-pin TSSOP package, while the ADS1256IDBT uses a 28-pin TSSOP package. The pin counts, pin functions, and PCB land patterns differ, so they are not drop-in replacements for each other.
How do the maximum data rates of the ADS1220IPWR and ADS1256IDBT compare?
The ADS1220IPWR supports programmable data rates up to 2 kSPS. The ADS1256IDBT supports data rates up to 30 kSPS. The ADS1256 is therefore better suited for higher-speed acquisition, while the ADS1220 targets lower-speed, high-resolution applications.
How many input channels does each device provide?
The ADS1220IPWR provides 4 input channels (configurable as 4 single-ended or 2 differential inputs). The ADS1256IDBT provides 8 input channels (configurable as 8 single-ended or 4 differential inputs). The ADS1256 offers twice the channel count of the ADS1220.
Do both devices include a programmable gain amplifier (PGA)?
Yes. Both the ADS1220IPWR and ADS1256IDBT integrate a programmable gain amplifier. The ADS1220 PGA supports gains from 1 to 128, and the ADS1256 PGA also supports gains from 1 to 64. The PGA allows direct connection of low-level sensors without external amplification.
What are the supply voltage requirements for the ADS1220IPWR and ADS1256IDBT?
The ADS1220IPWR operates from an analog supply (AVDD) of 2.3 V to 5.5 V and a digital supply (DVDD) of 2.3 V to 5.5 V. The ADS1256IDBT operates from an analog supply (AVDD) of 5 V (4.75 V to 5.25 V) and a digital supply (DVDD) of 1.8 V to 3.6 V. The ADS1220 offers a wider analog supply range, while the ADS1256 requires a 5 V analog supply.
Which device is more suitable for low-power portable applications?
The ADS1220IPWR is generally more suitable for low-power portable designs. It supports a wider analog supply range down to 2.3 V and offers low-power operating modes, making it adaptable to battery-powered systems. The ADS1256IDBT requires a 5 V analog supply and is oriented toward higher-throughput, multi-channel systems rather than ultra-low-power portability.
Can the ADS1220IPWR and ADS1256IDBT share the same SPI interface configuration?
Both devices use an SPI-compatible serial interface for communication with a host controller. However, the command sets, register maps, and timing specifications differ between the two devices. Firmware and driver software must be written specifically for each device; the interface protocol is not interchangeable without modification.