ADS7817U - 12-Bit 200kHz Differential ADC | Texas Instruments
MPN: ADS7817U ✓ ActiveADS7817U Overview
An ADC is an analog-to-digital converter, a data-acquisition IC that samples an analog voltage and converts it into a numeric code for processing or transmission. The ADS7817U belongs to the SAR ADC family, where successive-approximation conversion provides accurate measurement at relatively low power consumption. Its differential input structure supports measurement of the voltage difference between two analog nodes rather than measuring a single node relative to ground.
Key features of the ADS7817U include 12-bit resolution, a 200 kHz sampling rate, a fully differential input, and automatic power-down. The reference range of 100 mV to 2.5 V allows the converter to be matched to low-amplitude sensor signals. The manufacturer describes the device as micropower and identifies differential input, low power, automatic power-down, and small size as central advantages for direct sensor-interface applications.
The conversion performance is also supported by a serial interface suitable for embedded measurement systems. The serial output can be connected to a microcontroller or other digital controller for conversion and data processing. The differential input architecture is particularly useful when the source has a small signal amplitude and common-mode voltage varies, because the useful measurement is the difference between the two input nodes.
Typical applications include industrial process measurement, battery and power-system monitoring, sensor signal acquisition, portable instrumentation, and low-power embedded control. The ADS7817U is appropriate when the design requires a compact, low-power SAR converter with a differential input and a selectable reference range.
When laying out the circuit, use short, symmetrical analog traces and place the input and reference components close to the converter. Confirm the supply, reference, analog input, digital interface, and ground connections against the manufacturer datasheet before fabrication. Treat the differential input and reference network as precision signal paths rather than general-purpose routing.
Drop-in alternatives for ADS7817U — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ADS7817U (same form factor and footprint) — differing in Converter Type, Package, Resolution, Sampling Rate.
ADS7809U
✅ Drop-InContact for price
View Datasheet →ADS7817/2K5
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7817U Maximum Ratings & Electrical Characteristics
| Converter Type | SAR ADC |
| Resolution | 12 bit |
| Sampling Rate | 200 kHz |
| Input Architecture | Fully differential analog input |
| Input Impedance | High impedance |
| Reference Voltage Range | 100 mV to 2.5 V |
| Input-Referred Resolution | 49 uV to 1.22 mV |
| Power-Down Current | 3 uA maximum |
| Power Consumption | Micropower at 200 kHz |
| Input Range | Bipolar differential input |
| Interface | Serial interface |
| Package | 8-SOIC |
| Mounting Type | Surface mount |
| Operating Temperature Range | -40 C to +85 C |
| RoHS Status | Compliant |
| Lead-Free Status | Lead-free |
ADS7817U 8-soic Pin Configuration Guide
Pin configuration for ADS7817U (8-soic package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for ADS7817U.
Refer to the datasheet for full pin configuration.
Typical Applications
ADS7817U is suitable for 6 applications: Industrial Sensor Signal Acquisition, Battery and Power-System Monitoring, Portable Instrumented Measurement, Precision Process-Control Front End, Embedded Data Acquisition Module, Analog Feedback and Monitoring System.
Industrial Sensor Signal Acquisition
The ADS7817U suits low-level differential measurements from sensors in industrial monitoring equipment. Its 12-bit resolution and 200 kHz sampling rate provide a practical balance between measurement speed and power consumption, while the high-impedance fully differential input helps acquire the voltage difference between a sensor output and its reference node. Setting the reference to 100 mV yields 49 uV input-referred resolution according to the manufacturer product page, improving sensitivity to small changes within the analog signal. Place the sensor and converter on the same side of the divider network, route the differential pair symmetrically, and keep the reference path short to preserve the benefit of the low-reference operating range.
Recommended
Battery and Power-System Monitoring
The ADS7817U can monitor differential voltage changes in battery-management and power-system feedback circuits. The 200 kHz sampling rate allows repeated measurements of system dynamics, while automatic power-down and a 3 uA maximum shutdown current are useful when the converter operates intermittently. The differential input can reduce sensitivity to common-mode voltage if the signal source and converter share a suitable reference arrangement. For protection and control loops, the reference must remain within 100 mV to 2.5 V and the sampled signal must remain inside the device input limits. Use the manufacturer pin and electrical tables to establish startup sequencing, grounding, and digital-interface timing.
Recommended
Portable Instrumented Measurement
The ADS7817U is appropriate for compact handheld or portable test equipment where each milliampere of operating power affects battery life. Its micropower operation at 200 kHz, automatic shutdown capability, and 8-SOIC package help reduce board area and energy use. A 12-bit converter also provides enough nominal resolution for monitoring many slow or moderate-bandwidth analog quantities without using a larger multiplexed converter. For portable designs, enable the converter only during measurement bursts, select capacitors suitable for the reference network, and verify settling behavior between acquisition cycles. The serial interface reduces parallel wiring and supports compact connections to a low-power microcontroller.
Recommended
Precision Process-Control Front End
The ADS7817U can serve as the conversion stage in a process-control front end when the sensed variable is represented by a low-level differential voltage. The fully differential input supports cancellation of common-mode voltage, and the adjustable 100 mV to 2.5 V reference range lets designers match conversion resolution to the signal span. At the fastest stated 200 kHz sampling rate, the device is appropriate for supervisory control signals, though loop bandwidth and acquisition latency must be included in the control design. Use low-noise reference components and a symmetric PCB layout, and confirm input settling through the recommended application circuit rather than assuming the source impedance is unrestricted.
Recommended
Embedded Data Acquisition Module
The ADS7817U fits embedded acquisition modules that convert one analog differential channel and transfer the result through a serial interface. Its 200 kHz sampling rate supports responsive measurements, while 12-bit resolution limits code granularity according to the selected reference. The 8-SOIC package keeps the converter compact without requiring a large package with unused pins. In an embedded controller design, use the serial clock and data lines for isolated or short board-level communication, and confirm logic levels against the controlling device. Automatic power-down is particularly useful in cyclic acquisition systems, where the controller can disable the converter between bursts to reduce standby current.
Recommended
Analog Feedback and Monitoring System
The ADS7817U can digitize a differential feedback signal for supervision, diagnostics, or adaptive control in mixed-signal systems. Its high-impedance input avoids loading the measured node more than necessary, and the selectable reference supports either fine resolution on small signals or a wider range on larger signals. The 12-bit result is especially practical for supervisory loops where the controller must observe operating conditions without replacing the main high-resolution measurement channel. Keep the converter reference and analog input away from fast digital return currents, provide a quiet ground path, and follow the manufacturer grounding arrangement. Digital reads of the serial interface should be synchronized to the specified conversion and clock timing.
Recommended
Recommended Products Summary
Engineering reference data for ADS7817U — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS7809U | ADS7817/2K5 |
|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-SOIC | 8-SOIC | 8-SOIC |
| Resolution | 12 bit | 12 bit | 12 bit |
| Input Architecture | Fully differential | Differential | Fully differential |
| Reference Voltage | 100 mV to 2.5 V | 2.5 V reference option | 2.5 V |
| Interface | Serial | Serial | Serial |
Key Differentiators
- Lower nominal input-referred resolution with a reduced reference (vs ADS7817/2K5)
- Fully differential high-impedance input (vs ADS7809U)
- Low standby consumption with automatic power-down (vs ADS7817/2K5)
Design Notes
Route the differential analog input as a compact, symmetrical pair and keep it away from digital clock and serial-data traces. Place input and reference components close to their associated pins, and use a continuous ground plane without splitting return paths beneath the converter. The small reference range can improve nominal resolution to 49 uV, but reference noise, source impedance, and layout leakage can still affect the usable measurement noise.
Use the manufacturer recommended bypass capacitance and power-supply arrangement for the ADS7817U. Automatic power-down can reduce standby demand to no more than 3 uA, so control enable sequencing carefully when the converter shares a supply with sensitive analog circuitry. Confirm that reference settling and supply startup occur in the required order to avoid invalid early conversion results.
Do not treat the 12-bit nominal resolution as complete system accuracy. Include reference tolerance, analog front-end noise, source impedance, settling time, and differential-input common-mode limits in the error budget. Also verify the exact ordering suffix: ADS7817U and ADS7817/2K5 have different reference configurations, and a family-level comparison does not by itself prove that a device is a drop-in replacement.
Compliance Information
RoHS-compliant and lead-free status are identified for the ADS7817U. Other environmental, automotive, halogen-free, and conflict-minerals status requires manufacturer confirmation.
