Part A
ADS7809U
Texas Instruments
- Lifecycle
- Active
- Stock
- 6471 PCS
- Package
- SOIC-20
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7809U and ADS7800KU/1K are both 12-bit successive-approximation ADCs, but they differ in resolution architecture, package, and interface configuration, so the ADS7800KU/1K cannot serve as a direct drop-in substitute for the ADS7809U without design validation.
Different package type
Different interface configuration
Different conversion architecture
Different supply configuration
Parts at a glance
Part B
ADS7800KU/1K
Texas Instruments
- Lifecycle
- Active
- Stock
- 780 PCS
- Package
- SOIC-24
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS7809U | ADS7800KU/1K | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 12 bit | Resolution determines the smallest analog increment the ADC can distinguish; a 16-bit part offers 16x finer quantization than a 12-bit part, so they are not functionally interchangeable in precision applications. |
| Sampling Rate | 100 kSPS | 333 kSPS | Maximum throughput limits the bandwidth of signals that can be digitized; the faster ADS7800 supports higher-frequency inputs than the ADS7809. |
| Input Type | Single-ended | Single-ended | Input configuration affects how the signal source must be connected; both are single-ended, so the same front-end topology can generally be reused. |
| Interface | Serial (SPI/QSPI compatible) | Parallel | The digital interface dictates the host connection and pin count; a serial device uses fewer I/O lines while a parallel device offers faster data transfer, so board redesign is required when swapping. |
| Supply Voltage | 5 V (single supply) | 5 V and -15 V (dual supply) | Supply requirements determine power rail design; the ADS7800 needs an additional negative rail, so it cannot drop into a single-supply socket without hardware changes. |
| Analog Input Range | ±10 V | ±10 V | The full-scale input span must match the signal source to avoid clipping or loss of dynamic range; both parts accept the same ±10 V range. |
| Package | 28-pin SOIC | 28-pin SOIC | Package and pinout determine physical and footprint compatibility; identical SOIC packages ease mechanical substitution but pin functions still differ. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range defines the environments in which the part is guaranteed to meet specifications; matching ranges mean similar application suitability. |
| Integral Nonlinearity (INL) | ±2 LSB (max) | ±0.5 LSB (max) | INL measures deviation from an ideal transfer function; the tighter INL of the ADS7800 provides better absolute accuracy relative to its resolution. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7809U | ADS7800KU/1K |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 12 |
| Sampling Rate(Per Second) | 100k | 333k |
| Number of Inputs | 1 | 1 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, DSP | Parallel |
| 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, Internal | Internal |
| Voltage - Supply, Analog | 5V | 5V, -11.4V ~ 16.5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the ADS7809U and the ADS7800KU/1K?
The ADS7809U is a 16-bit successive-approximation ADC with a serial (SPI-compatible) interface, while the ADS7800KU/1K is a 12-bit successive-approximation ADC with a parallel interface. The ADS7809U offers higher resolution (16-bit vs 12-bit) and a serial output, whereas the ADS7800KU/1K provides a parallel data bus and lower resolution. Both are single-channel, monolithic ADCs from Texas Instruments (Burr-Brown), but they differ in resolution, interface type, and package/pinout.
Are the ADS7809U and ADS7800KU/1K pin-compatible or package-compatible?
No. The ADS7809U is supplied in a 28-pin SOIC (DW) package, while the ADS7800KU/1K is supplied in a 24-pin SOIC (DW) package. The pin counts and pin functions differ, so they are not drop-in replacements and require different PCB footprints.
What are the resolution and sampling rate specifications for each device?
The ADS7809U provides 16-bit resolution with a maximum sampling rate of 100 kSPS. The ADS7800KU/1K provides 12-bit resolution with a maximum sampling rate of 333 kSPS. The ADS7800KU/1K therefore offers a higher throughput at lower resolution, while the ADS7809U prioritizes resolution over speed.
How do the digital interfaces of the ADS7809U and ADS7800KU/1K differ?
The ADS7809U uses a serial interface compatible with SPI and similar synchronous serial protocols, outputting data on a single serial data line with associated clock and frame signals. The ADS7800KU/1K uses a parallel interface with a 12-bit-wide data bus plus control signals. System designers must account for this difference in microcontroller or FPGA I/O requirements when comparing the two parts.
Do the ADS7809U and ADS7800KU/1K have the same analog input range and reference requirements?
Both devices support bipolar analog input ranges and require an external reference for full-scale definition, but the exact input span configuration and reference voltage requirements should be verified against the respective Texas Instruments datasheets. The ADS7809U supports software-selectable input ranges, while the ADS7800KU/1K input range configuration is set per its datasheet. Designers must confirm reference and input-range settings for each part individually.
Can the ADS7809U directly replace the ADS7800KU/1K in an existing design?
No. Because the two devices differ in resolution (16-bit vs 12-bit), interface type (serial vs parallel), package pin count (28-pin vs 24-pin), and sampling rate, a direct replacement is not possible. Any substitution requires a redesign of the digital interface, PCB footprint, and system firmware, followed by validation against the target device's datasheet.
Which device is better suited for high-resolution, low-speed measurement applications?
The ADS7809U is better suited for high-resolution, lower-speed applications because it provides 16-bit resolution at up to 100 kSPS, making it appropriate for precision measurement, instrumentation, and data-acquisition systems where accuracy is prioritized over throughput. The ADS7800KU/1K, with 12-bit resolution and up to 333 kSPS, is better suited for faster, lower-resolution applications.