Part A
ADS1220IPW
Техасские инструменты
- Lifecycle
- Active
- Stock
- 4062 ПКС
- Package
- TSSOP-16
- Series
- Сбор данных - аналогово-цифровые преобразователи (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1220IPW and ADS1208IPWR are not functionally interchangeable. The ADS1220IPW is a 24-bit precision delta-sigma ADC with an integrated PGA and SPI interface, while the ADS1208IPWR is a 16-bit second-order delta-sigma modulator with a single-bit output stream. They differ in resolution, output interface, input architecture, and package pinout, so the ADS1208IPWR cannot directly replace the ADS1220IPW in an existing design without significant rework.
Different output interface
Different resolution
Different input architecture
Different package pinout
Parts at a glance
Part B
ADS1208IPWR
Техасские инструменты
- Lifecycle
- Active
- Stock
- 7626 ПКС
- Package
- TSSOP-16
- Series
- Сбор данных - ADC-DAC - Специальное назначение
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS1220IPW | ADS1208IPWR | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 16 | Higher resolution enables finer measurement of small signal changes; a 24-bit ADC can resolve much smaller increments than a 16-bit device. |
| Architecture | Delta-Sigma (with PGA and input mux) | Delta-Sigma modulator | The ADS1220 integrates a PGA and multiplexer for direct sensor connection, while the ADS1208 is a modulator requiring external digital filtering, affecting system complexity. |
| Number of input channels | 4 (differential/ single-ended via mux) | 1 (differential) | More input channels allow multiple sensors to be measured by one device, reducing component count in multi-channel systems. |
| Interface type | SPI | Serial digital (modulator bitstream) | SPI provides a standard register-based interface, whereas the ADS1208 outputs a raw modulator bitstream that must be processed by an external digital filter. |
| Integrated PGA | Yes | No | An integrated PGA allows direct amplification of low-level sensor signals without external gain stages, simplifying the analog front end. |
| Supply voltage (analog) | 2.3 V to 5.5 V | 4.5 V to 5.5 V | A wider supply range enables operation from lower-voltage rails, which is important for battery-powered and low-voltage systems. |
| Package | TSSOP-16 | TSSOP-16 | Package compatibility affects PCB footprint and assembly; identical packages ease board-level substitution. |
| Operating temperature range | -40 °C to +125 °C | -40 °C to +85 °C | A wider temperature range supports use in harsh environments and industrial applications requiring extended thermal tolerance. |
| Data rate / output rate | Up to 2000 SPS | Up to 40 kSPS (modulator clock dependent) | Output rate determines measurement throughput; the ADS1208 modulator supports higher raw sampling rates when paired with an appropriate digital filter. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1220IPW | ADS1208IPWR |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Type | - | Modulator |
| Number of Channels | - | 1 |
| Resolution(Bits) | - | 16 b |
| Sampling Rate(Per Second) | 2k | 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 ~ 125°C | -40°C ~ 85°C |
| Mounting Type | - | Surface Mount |
| Number of Bits | 24 | - |
| Number of Inputs | 2, 4 | - |
| Input Type | Differential, Single Ended | - |
| Configuration | MUX-PGA-ADC | - |
| Number of A/D Converters | 1 | - |
| Architecture | Sigma-Delta | - |
| Reference Type | External, Internal, Supply | - |
| Voltage - Supply, Analog | 2.3V ~ 5.5V, ±2.5 | - |
| Voltage - Supply, Digital | 2.3V ~ 5.5V | - |
| Features | PGA, Temperature Sensor | - |
Frequently asked questions
What are the primary functional differences between the ADS1220IPW and ADS1208IPWR?
The ADS1220IPW is a 24-bit, 4-channel, delta-sigma analog-to-digital converter (ADC) with an integrated programmable gain amplifier (PGA), voltage reference, and SPI interface, housed in a TSSOP-16 package. The ADS1208IPWR is a 16-bit, single-channel, second-order delta-sigma modulator with a differential input and a digital filter interface, housed in a TSSOP-16 package. The ADS1220 integrates a complete ADC signal chain, while the ADS1208 provides a modulated bitstream requiring external digital filtering.
Are the ADS1220IPW and ADS1208IPWR pin-compatible and directly interchangeable?
No. Although both devices are offered in a TSSOP-16 package, their pin functions and internal architectures differ. The ADS1220IPW provides SPI communication, PGA inputs, and reference pins, whereas the ADS1208IPWR provides a modulator clock input and a single-bit data output. A direct drop-in replacement is not possible without redesigning the interface and signal chain.
What are the resolution and data rate specifications of each device?
The ADS1220IPW offers up to 24-bit resolution with programmable data rates from 5 SPS to 2,000 SPS. The ADS1208IPWR is a 16-bit modulator with a typical clock frequency of 10 MHz and an oversampling ratio that determines effective resolution and output data rate when paired with an external digital filter.
Which device is better suited for directly digitizing low-level sensor signals?
The ADS1220IPW is better suited for direct low-level sensor digitization because it integrates a low-noise PGA, a precision voltage reference, and an internal oscillator, allowing direct connection of thermocouples, RTDs, and bridge sensors. The ADS1208IPWR requires external signal conditioning, a modulator clock, and a digital filter to produce a usable digital output.
Do both devices support the same supply voltage range?
No. The ADS1220IPW operates from an analog supply of 2.3 V to 5.5 V and a digital supply of 2.3 V to 5.5 V. The ADS1208IPWR operates from a single 5 V supply (4.5 V to 5.5 V) for both analog and digital sections. Power-supply design must account for these differences.
What interface does each device use to communicate with a host controller?
The ADS1220IPW uses a 4-wire SPI-compatible serial interface for configuration, data readout, and register access. The ADS1208IPWR outputs a single-bit delta-sigma modulated data stream and requires an external digital filter or a microcontroller with an appropriate modulator interface to reconstruct the digital word.
Can the ADS1208IPWR be used as a replacement for the ADS1220IPW in an existing SPI-based design?
No. The ADS1208IPWR does not provide an SPI interface or integrated PGA and reference. Replacing an ADS1220IPW with an ADS1208IPWR would require adding a modulator clock source, an external digital filter, and external signal conditioning, which constitutes a significant redesign rather than a substitution.