Part A
ADS1246IPWR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2336 PCS
- Package
- TSSOP-16
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1246IPWR and ADS1208IPWRG4 are not functionally interchangeable. The ADS1246IPWR is a 24-bit delta-sigma ADC with an integrated PGA and SPI interface, while the ADS1208IPWRG4 is a 16-bit second-order delta-sigma modulator with a single-bit output stream. They differ in resolution, output interface, analog front-end architecture, and package pinout, so substituting one for the other would require a complete redesign of the signal chain and board layout.
Different output interface
Different resolution
Different analog front-end
Different pinout
Parts at a glance
Part B
ADS1208IPWRG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 4872 PCS
- Package
- TSSOP-16
- Series
- Acquisition de données - ADC DAC - dédié
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS1246IPWR | ADS1208IPWRG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 16 | Resolution determines the smallest signal change the converter can distinguish; a 24-bit delta-sigma ADC offers far finer resolution than a 16-bit device. |
| Architecture | Delta-Sigma (precision ADC) | Delta-Sigma modulator | The ADS1246 is a complete precision ADC with digital filter and SPI interface, while the ADS1208 is a modulator that outputs a bitstream requiring external digital filtering, affecting system design and substitutability. |
| Number of input channels | 1 differential (2 single-ended) | 1 differential | Channel count determines how many signals can be measured; the ADS1246 supports flexible single-ended or differential input configurations. |
| Output interface | SPI (digital) | 1-bit modulator bitstream | The output format dictates how the host processor receives data; SPI provides ready-to-use digital codes, whereas a bitstream requires an external digital filter (e.g., sinc filter). |
| Supply voltage (analog) | 2.7 V to 5.25 V | 4.5 V to 5.5 V | Supply range affects compatibility with the system power rail; the ADS1246 operates over a wider low-voltage range, while the ADS1208 requires a nominal 5 V supply. |
| Data rate / output rate | Up to 2 kSPS | Up to 40 kSPS (modulator clock dependent) | Output rate determines measurement bandwidth and speed; the ADS1208 modulator supports higher sampling rates for faster control loops. |
| Integrated PGA | Yes (gain 1 to 128) | No | An integrated programmable gain amplifier allows direct connection of low-level sensors without external amplification, simplifying the signal chain. |
| Package | TSSOP-16 | TSSOP-16 | Package footprint and pinout affect board layout and drop-in compatibility; both share the same TSSOP-16 package but differ in pin function. |
| Operating temperature range | -40 °C to +105 °C | -40 °C to +85 °C | Temperature range determines suitability for harsh or industrial environments; the ADS1246 supports a wider operating range. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1246IPWR | ADS1208IPWRG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| 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 ~ 105°C | -40°C ~ 85°C |
| Mounting Type | - | Surface Mount |
| Number of Bits | 24 | - |
| Number of Inputs | 1 | - |
| Input Type | Differential, Single Ended | - |
| Configuration | MUX-PGA-ADC | - |
| Number of A/D Converters | 1 | - |
| Architecture | Sigma-Delta | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 2.7V ~ 5.25V | - |
| Voltage - Supply, Digital | 2.7V ~ 5.25V | - |
| Features | PGA, Temperature Sensor | - |
Frequently asked questions
What are the primary functional differences between the ADS1246IPWR and ADS1208IPWRG4?
The ADS1246IPWR is a 24-bit delta-sigma analog-to-digital converter (ADC) with a built-in programmable gain amplifier (PGA) and SPI interface, designed for precision sensor measurement. The ADS1208IPWRG4 is a 16-bit delta-sigma modulator with a ±250 mV input range and a digital filter interface, intended for isolated current sensing and shunt-based measurement applications. They differ in resolution, input architecture, and output interface.
Are the ADS1246IPWR and ADS1208IPWRG4 pin-compatible?
No. The ADS1246IPWR is supplied in a TSSOP-20 package, while the ADS1208IPWRG4 is supplied in a TSSOP-16 package. The differing pin counts and pin functions prevent direct PCB footprint compatibility.
Can the ADS1246IPWR and ADS1208IPWRG4 be used interchangeably in an existing design?
No. The ADS1246IPWR provides a complete ADC with digital output over SPI, whereas the ADS1208IPWRG4 outputs a 1-bit modulator stream requiring an external digital filter (e.g., FPGA or DSP). Their interfaces, supply requirements, and signal chains differ, so substitution requires redesign of the digital interface and filtering.
What are the resolution and data rate characteristics of each device?
The ADS1246IPWR offers 24-bit resolution with programmable data rates up to 2 kSPS. The ADS1208IPWRG4 is a 16-bit modulator with a typical clock frequency of 10 MHz and an oversampling ratio that determines effective resolution and bandwidth through the external digital filter.
What input signal ranges do these devices support?
The ADS1246IPWR supports differential inputs with a programmable gain amplifier, allowing small sensor signals to be amplified before conversion. The ADS1208IPWRG4 has a fixed ±250 mV input range, making it suitable for direct shunt resistor voltage measurement in current-sensing applications.
Which device is better suited for isolated current sensing?
The ADS1208IPWRG4 is specifically designed for current sensing with a ±250 mV input and a modulator output that can be galvanically isolated via a digital isolator, making it well suited for isolated shunt-based current measurement. The ADS1246IPWR is a general-purpose precision ADC and is not optimized for this isolated modulator architecture.
Do both devices operate from the same supply voltage?
No. The ADS1246IPWR operates from a single 2.7 V to 5.25 V analog supply with a separate digital supply. The ADS1208IPWRG4 operates from a 5 V analog supply and a 3 V to 5.5 V digital supply. Designers must verify supply rail compatibility against the respective datasheets.