Part A
ADS7809U
Texas Instruments
- Lifecycle
- Active
- Stock
- 6471 PCS
- Package
- SOIC-20
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS7804UB is a viable functional replacement candidate for the ADS7809U, sharing the same 12-bit SAR architecture, 5 V supply, and 28-pin SOIC footprint, though the designer must validate the faster 10 µs conversion time, the narrower 0 V to 4 V input range, and the absence of the internal reference buffer before committing to the substitution.
Resolution and Architecture
High match
Package and Pinout
High match
Analog Input Range
Validation required
Conversion Time
Validation required
Parts at a glance
Part B
ADS7804UB
Burr Brown
- Lifecycle
- Active
- Stock
- 7035 PCS
- Package
- SOIC-28
- 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 | ADS7804UB | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 12 bit | Resolution determines the smallest analog signal change the ADC can distinguish; a 16-bit device offers far finer quantization than a 12-bit device, so they are not functionally interchangeable in precision applications. |
| Sampling Rate | 100 kSPS | 100 kSPS | Throughput sets the maximum signal bandwidth the converter can digitize; matching rates mean timing budgets are similar, but resolution differences still dominate substitutability. |
| Input Type | Single-ended | Single-ended | Input configuration must match the signal source topology; both being single-ended simplifies direct replacement at the analog front end. |
| Interface | Parallel (byte/word) | Parallel (12-bit) | The digital interface must match the host bus width and protocol; differing data bus formats affect wiring and firmware, complicating drop-in substitution. |
| Supply Voltage | 5 V | 5 V | Supply voltage compatibility ensures the part operates in the same rail environment; identical 5 V operation supports reuse of the existing power design. |
| Package | 28-SOIC | 28-SOIC | Package and pinout determine board footprint and solderability; matching SOIC packages allow the same PCB land pattern to be used. |
| INL (Integral Nonlinearity) | ±1.5 LSB (typ) | ±0.5 LSB (typ) | INL measures deviation from an ideal transfer function and directly affects accuracy; the tighter INL of the 12-bit part reflects its different resolution and accuracy class. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range confirms suitability for industrial environments; identical ratings mean both can serve the same application conditions. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7809U | ADS7804UB |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 16 | 12 |
| Sampling Rate(Per Second) | 100k | 100k |
| 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 | External, Internal |
| Voltage - Supply, Analog | 5V | 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 ADS7804UB?
The ADS7809U is a 16-bit successive-approximation ADC with a 10 µs conversion time and a 100 kHz sampling rate, while the ADS7804UB is a 12-bit successive-approximation ADC with a 10 µs conversion time and a 100 kHz sampling rate. The primary difference is resolution (16-bit vs 12-bit), along with corresponding differences in linearity, SNR, and output data format.
Are the ADS7809U and ADS7804UB pin-compatible?
Yes. Both devices are offered in the same 28-pin SOIC (DW) package and share a compatible pinout, including the parallel data bus, control signals (CS, R/C, BYTE, BUSY), and analog input pins. This allows the ADS7804UB to be used as a drop-in replacement in many existing ADS7809U sockets, provided the system can accept 12-bit resolution.
What is the analog input voltage range for each device?
Both the ADS7809U and ADS7804UB feature a ±10 V bipolar analog input range with a 20 V peak-to-peak span. The input configuration is set via the internal reference and external connections, supporting both bipolar and unipolar modes depending on the wiring of the reference and input pins.
Do both parts use the same internal reference voltage?
Yes. Both the ADS7809U and ADS7804UB integrate an internal 2.5 V reference. The reference is used to establish the full-scale input range, and both devices allow the internal reference to be overdriven by an external reference if higher accuracy or a different range is required.
How do the SNR and THD specifications compare?
The ADS7809U, being a 16-bit converter, specifies a signal-to-noise ratio (SNR) of typically 87 dB and total harmonic distortion (THD) of typically −95 dB. The ADS7804UB, as a 12-bit converter, specifies SNR of typically 72 dB and THD of typically −80 dB. These differences reflect the resolution and linearity capabilities of each device.
What is the maximum sampling rate and conversion time for both devices?
Both the ADS7809U and ADS7804UB have a maximum sampling rate of 100 kHz and a conversion time of 10 µs. The acquisition time and throughput are identical, so the choice between them is driven by resolution and accuracy requirements rather than speed.
What digital interface and output format do these ADCs provide?
Both devices provide a parallel digital interface with a 16-bit-wide data bus for the ADS7809U and a 12-bit-wide data bus for the ADS7804UB. The output data is available in two's complement or straight binary format, selectable via the BYTE and control pins, and both support byte-swapping for 8-bit microprocessor interfaces.
What are the operating temperature ranges and package options?
Both the ADS7809U and ADS7804UB are specified for the industrial temperature range of −40 °C to +85 °C and are available in a 28-pin SOIC (DW) package. The "U" and "UB" suffixes denote the SOIC package and grade, respectively, and both parts are RoHS-compliant.