Part A
ADS7822U
Texas Instruments
- Lifecycle
- Active
- Stock
- 7079 PCS
- Package
- SOIC-8
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7822U and ADS7808U/1K are not drop-in replacements for one another. Although both are 12-bit successive-approximation ADCs, they differ in resolution architecture, sampling rate, package footprint, and supply voltage range, so the ADS7808U/1K cannot be substituted directly for the ADS7822U without circuit and layout redesign.
Different sampling rate
Different package footprint
Different supply voltage range
Different interface timing
Parts at a glance
Part B
ADS7808U/1K
Texas Instruments
- Lifecycle
- Active
- Stock
- 9730 PCS
- Package
- SOIC-20
- 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 | ADS7822U | ADS7808U/1K | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Sampling Rate | 75 kSPS | 100 kSPS | The ADS7808U offers a higher maximum throughput, which matters for faster signal acquisition requirements. |
| Number of Input Channels | 1 (single-ended) | 1 (single-ended) | Both are single-channel devices, so channel count does not affect substitutability. |
| Input Type | Single-ended | Single-ended | Identical input configuration means the same signal source topology can be used. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V (single supply) | The ADS7822U supports lower supply voltages, enabling use in low-power 3.3 V systems where the ADS7808U cannot operate. |
| Interface | SPI / QSPI / Microwire (serial) | Parallel | Different digital interfaces require different host connections, so they are not directly drop-in interchangeable. |
| Package | SOIC-8 | SOIC-28 | Different package footprints and pin counts prevent direct board-level substitution. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings mean both suit the same environmental conditions. |
| Power Consumption | Low power (micropower, ~1.6 mW at 5 V) | Higher power (~100 mW typical) | The ADS7822U is significantly lower power, which is critical for battery-powered or energy-sensitive designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7822U | ADS7808U/1K |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 200k | 100k |
| Number of Inputs | 1 | 1 |
| Input Type | Pseudo-Differential | Single Ended |
| Data Interface | SPI | SPI, DSP |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External | External, Internal |
| Voltage - Supply, Analog | 2.7V ~ 3.6V, 5V | 5V |
| Voltage - Supply, Digital | 2.7V ~ 3.6V, 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Series | microPOWER™ | - |
Frequently asked questions
What are the key architectural differences between the ADS7822U and the ADS7808U/1K?
The ADS7822U is a 12-bit, micropower, successive-approximation register (SAR) analog-to-digital converter (ADC) that operates from a single 2.7 V to 5.25 V supply and communicates via a synchronous serial (SPI-compatible) interface. The ADS7808U/1K is a 12-bit SAR ADC that operates from a single 5 V supply and provides a parallel 8-bit/12-bit data bus interface. The ADS7822U is optimized for low power and small package size, while the ADS7808U/1K is designed for higher throughput parallel-interface applications.
Are the ADS7822U and ADS7808U/1K pin-compatible or package-compatible?
No. The ADS7822U is supplied in an 8-pin SOIC (D) package, while the ADS7808U/1K is supplied in a 28-pin SOIC (DW) package. The pin counts, pin functions, and PCB land patterns differ, so these devices are not drop-in replacements for one another.
How do the sampling rates of the ADS7822U and ADS7808U/1K compare?
The ADS7822U offers a maximum sampling rate of 75 kSPS at a 5 V supply (and 75 kSPS at 2.7 V). The ADS7808U/1K offers a maximum sampling rate of 100 kSPS. The ADS7808U/1K therefore provides a higher maximum throughput, while the ADS7822U targets lower-power, lower-speed applications.
What are the power consumption characteristics of each device?
The ADS7822U is specified for micropower operation, drawing approximately 1.6 mW at 75 kSPS with a 5 V supply, and it features a power-down mode that reduces consumption to microwatt levels between conversions. The ADS7808U/1K typically dissipates approximately 100 mW from a 5 V supply during normal operation. The ADS7822U is therefore significantly better suited to battery-powered and portable systems.
What digital interface does each ADC provide?
The ADS7822U provides a synchronous serial interface compatible with SPI, QSPI, and Microwire, using a serial clock, serial data output, and chip-select/frame-sync signals. The ADS7808U/1K provides a parallel interface with a 12-bit data output available as a full 12-bit word or as two 8-bit bytes, along with standard control signals such as CS, R/C, and BYTE. The choice depends on whether the host system favors a serial or parallel bus.
What are the analog input configurations of the ADS7822U and ADS7808U/1K?
The ADS7822U provides a single pseudo-differential analog input pair (IN+ and IN−) and is specified for a 0 V to VREF unipolar input range. The ADS7808U/1K provides a single-ended analog input with a 0 V to 10 V unipolar input range (using its internal or external reference). The input signal conditioning and reference requirements therefore differ between the two devices.
Do both devices include an internal voltage reference?
No. The ADS7822U requires an external reference voltage applied to the VREF pin and does not include an internal reference. The ADS7808U/1K includes an internal 2.5 V reference (with the input range scaled to 0 V to 10 V) and also allows use of an external reference. This difference affects system-level component count and accuracy budgeting.
In what applications would the ADS7822U be preferred over the ADS7808U/1K, and vice versa?
The ADS7822U is preferred in portable, battery-powered, and space-constrained systems that require low power, a small 8-pin package, and a serial interface, such as handheld instruments and remote sensors. The ADS7808U/1K is preferred in systems that need a parallel microprocessor bus interface, a wider 0 V to 10 V input range, an internal reference, and higher throughput, such as industrial data acquisition and control systems.