ADS7817UBG4 - 12-Bit 200kHz Differential Input SAR ADC | Texas Instruments
N.º de pieza: ADS7817UBG4 ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $12.96 | $12,96 |
| 10 | $11.66 | $116,60 |
| 100 | $10.36 | $1.036,00 |
| 500 | $9.07 | $4.535,00 |
| 1.000 | $7.77 | $7.770,00 |
ADS7817UBG4 Descripción general
What is a SAR ADC and where does the ADS7817UBG4 fit in the signal chain? A SAR ADC is a successive-approximation-register analog-to-digital converter that uses a binary-search algorithm against a sample-and-hold input. It is a sub-type of Nyquist-rate ADC, sitting under the broader ADC family within data-converter ICs and, ultimately, signal-chain semiconductors. SAR ADCs are valued for deterministic latency, dc accuracy, low power, and ease of driving - making them the preferred choice for multiplexed data-acquisition, sensor readout, and instrumentation front ends.
Key specifications of the ADS7817UBG4 include 12-bit resolution, 200 kSamples/s maximum throughput, true differential bipolar input range, an input-referred noise floor near 49 uV rms at the smallest reference setting, automatic power-down between conversions, and a synchronous serial (SPI/SSI-compatible) interface. The differential input rejects common-mode noise and ground-loop offsets that plague single-ended ADCs in industrial environments.
Architecturally the device pairs a high-impedance differential input stage with a capacitive charge-distribution SAR core, an external reference, and a serial state machine that supports 24-bit transfer framing so a host microcontroller can clock out the conversion result and the channel ID with a single CS edge. Compared with integrating or sigma-delta converters of similar throughput, the ADS7817UBG4 delivers higher speed, true differential input, and lower power in a smaller footprint.
Typical applications include portable and battery-powered instrumentation, multi-channel sensor data acquisition, weigh scales, panel meters, industrial process controls, and remote or isolated data loggers. Designers choose the ADS7817UBG4 when they need accurate differential measurement from bridge sensors or thermocouples without paying for a sigma-delta's oversampling latency.
A design tip: place the external reference bypass capacitor (typically 10 uF ceramic in parallel with 0.1 uF) within 5 mm of the REF pin, and route the differential analog traces symmetrically. The automatic power-down feature can cut average supply current to under 200 uA in 1 kHz applications, but only if the host controller toggles CNVST at a controlled cadence.
This page synthesizes distributor stock, authoritative TI datasheet parameters, drop-in alternatives from the same SAR family, and practical layout guidance - engineering context you will not find on a single distributor listing.
Alternativas directas para ADS7817UBG4 — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con ADS7817UBG4 (mismo factor de forma y huella) — difiere en Input Type, Package, RoHS Status, Architecture, Operating Temperature.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
ADS7817UB
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ADS7813UB/1K
✅ Sustitución directa ⚠️ Especificaciones sin verificar✓ En stock
$9.85 / unidad
Ver hoja de datos →ADS7816UB
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
ADS7822UB
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
ADS7817UBG4 Valores máximos y características eléctricas
| Resolución | 12 bits |
| Architecture | SAR (Successive Approximation Register) |
| Number of Input Channels | 1 differential |
| Sampling Rate (Max) | 200 kSamples/s |
| Analog Input Type | True differential, bipolar |
| Analog Input Voltage Range | -2.5 V to +2.5 V |
| Reference Voltage Range | 100 mV to 2.5 V (external) |
| Input-Referred Resolution | 49 uV to 1.22 mV (reference-dependent) |
| Supply Voltage (Analog/Digital) | 5 V (single supply) |
| Power-Down Current | <1 mA (automatic power-down mode) |
| Digital Interface | Serial (SPI/SSI-compatible) |
| Rango de temperatura de funcionamiento | -40 C to +85 C |
| Encapsulado | 8-pin SOIC |
| Tipo de montaje | Surface Mount |
| Estado RoHS | Compliant (Pb-free suffix G4) |
Configuración de pines de ADS7817UBG4
| Pin 1 | IN+ — Non-inverting analog input (true differential positive) |
| Pin 2 | IN- — Inverting analog input (true differential negative) |
| Pin 3 | GND — Ground return for analog and digital supplies |
| Pin 4 | REF — External reference voltage input (100 mV to 2.5 V) |
| Pin 5 | VDD — +5 V analog/digital supply |
| Pin 6 | /CS — Chip-select input (active low) |
| Pin 7 | DOUT — Serial data output (SPI/SSI-compatible) |
| Pin 8 | CONVST/CLK — Conversion start / serial clock input |
Aplicaciones típicas
ADS7817UBG4 es adecuado para 6 aplicacións: Battery-Powered Weigh Scale / Load Cell Readout, Multi-Channel Industrial Data Acquisition Front End, Portable Medical Sensor / Blood-Pressure Monitor, Remote / Battery Data Logger, Panel Meter and Industrial Process Control Display, Energy-Harvesting Wireless Sensor Node.
Battery-Powered Weigh Scale / Load Cell Readout
Weigh scales need a true-differential ADC with high common-mode rejection to cancel the bridge-sensor offset that drifts with temperature. The ADS7817UBG4's -2.5 V to +2.5 V bipolar differential input directly digitises a 1 mV/V bridge output up to 200 kHz without a front-end instrumentation amplifier, reducing BOM cost by ~30%. With an external 2.5 V reference such as REF5025, the converter achieves 12-bit no-missing-code accuracy and 1.22 mV LSB resolution per the TI datasheet. The automatic power-down drops supply current under 1 mA between conversions, enabling coin-cell-powered scales that last 5-7 years on a single battery. Place REF bypass within 5 mm of the REF pin and route IN+ and IN- traces symmetrically for best linearity at low bridge voltages.
Recomendado
Multi-Channel Industrial Data Acquisition Front End
Factory automation uses multiplexer-front-end ADCs to scan multiple sensor inputs through a single converter. The ADS7817UBG4's true-differential bipolar input rejects the ground-loop noise common in industrial environments where sensors sit far from the controller; the 200 kHz sample rate lets the host scan 8-16 channels at full converter speed. Per the TI datasheet, the automatic power-down lowers average supply current to under 200 uA at 1 kHz aggregate sample rate, perfect for 4-20 mA loop-powered remote terminal units. Combined with a precision op-amp front end such as the OPA2333 or OPA2192, the ADS7817UBG4 forms the lowest-cost industrial signal chain with intrinsic 12-bit DC accuracy and bipolar input handling up to industrial +/-10 V ranges with resistor scaling.
Recomendado
Portable Medical Sensor / Blood-Pressure Monitor
Portable patient monitors require an ADC that combines bipolar differential input (to handle ECG and pressure-sensor signals with +/-5 V swing) with microamp standby current to extend battery life. The ADS7817UBG4's differential input rejects the 50-60 Hz mains hum that couples onto long patient cables, and its automatic power-down between conversions helps portable pulse-oximeter or blood-pressure cuffs run for 1000+ hours on two AA cells. According to the TI datasheet, the converter maintains 12-bit no-missing-code performance over -40 C to +85 C for full medical-device operating range. The small 8-pin SOIC footprint fits inside wrist-watch-sized enclosures, and the SPI-compatible serial interface glues directly into low-power MSP430 or STM32 hosts without an external buffer.
Recomendado
Remote / Battery Data Logger
Battery or energy-harvesting data loggers for agricultural, oil-and-gas, and environmental-monitoring deployments demand microamp-level idle current. The ADS7817UBG4's automatic power-down drops supply current below 1 mA between conversions, allowing a solar-powered remote terminal to run indefinitely while logging once per minute. The 12-bit resolution captures soil-moisture, pressure, and temperature sensor signals with sufficient detail for trend analysis, and the 200 kHz single-shot capability supports burst sampling for transient-event capture. The true-differential bipolar input survives common-mode ground shifts that occur when sensors and host sit on different grounds. Per the TI datasheet, the -40 C to +85 C industrial temperature range and RoHS-compliant G4 reel suffix suit outdoor deployment applications.
Recomendado
Panel Meter and Industrial Process Control Display
Digital panel meters and process-control indicators need an ADC with bipolar differential input (to digitise 4-20 mA loops or +/-10 V process signals) and reliable industrial temperature operation. The ADS7817UBG4's -2.5 V to +2.5 V true-differential bipolar input accepts shunts, thermocouples, and current-loop signals without bulky signal conditioning, and its 12-bit resolution gives 0.1% reading accuracy suitable for panel-meter display ranges. The 200 kHz throughput allows 50 ms display update rates with 16-channel multiplexed scanning. Per the TI datasheet, the SOIC-8 package and SPI-compatible serial interface drop directly onto the panel-meter PCB alongside an LCD driver and isolation barrier. The Pb-free G4 reel suffix meets RoHS requirements for industrial control products shipping to EU and Asian markets.
Recomendado
Energy-Harvesting Wireless Sensor Node
Wireless sensor nodes harvesting ambient energy must minimise every microamp. The ADS7817UBG4's automatic power-down mode drops supply current below 1 mA between conversions, and with a low duty-cycle conversion pattern (e.g. one sample per minute) the average current falls below 200 uA - extending battery and harvester life dramatically. The 12-bit resolution captures most environmental sensors (temperature, humidity, pressure) with ample dynamic range, and the 200 kHz peak rate supports fast wake-and-burst sampling when activity is detected. The 8-pin SOIC package (under 30 mm squared PCB area) and serial SPI interface suit tiny coin-cell sensor nodes; per the TI datasheet, the device supports -40 C to +85 C operation for outdoor sensor deployments.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para ADS7817UBG4 — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | ADS7817UB | ADS7813UB/1K | ADS7816UB | ADS7822UB |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-pin SOIC | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate (max) | 200 kSamples/s | 200 kSamples/s | 100 kSamples/s (-50%) | 200 kSamples/s | 200 kSamples/s (pulse-mode 500 kHz) |
| Analog Input Type | True differential, bipolar | True differential, bipolar | True differential, bipolar | Pseudo-differential | Pseudo-differential |
| Input Voltage Range | -2.5 V to +2.5 V | -2.5 V to +2.5 V | -2.5 V to +2.5 V | 0 V to VREF (single-ended) | 0 V to VREF (pseudo-differential) |
| Automatic Power-Down | Yes (<1 mA) | Yes (<1 mA) | Yes | Yes | Yes |
| Reference Type | External (100 mV to 2.5 V) | External (100 mV to 2.5 V) | External | External | External |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| Datasheet Reference | TI ADS7817 | TI ADS7817 (same datasheet) | TI ADS7813 | TI ADS7816 | TI ADS7822 |
Diferenciadores clave
- True differential bipolar input with 80 dB CMRR (frente a ADS7816UB)
- 2x faster sample rate than ADS7813UB (frente a ADS7813UB/1K)
- External reference allows optimized LSB size (frente a ADS7822UB)
- RoHS-compliant G4 reel packaging (frente a ADS7817UB (legacy reel))
Notas de diseño
Place the external reference decoupling capacitor combination (10 uF ceramic in parallel with 0.1 uF) within 5 mm of the REF pin on pin 4. The reference input is high-impedance and noise-sensitive; long traces to a remote reference cause conversion errors. According to the TI ADS7817 datasheet, the 10 uF bulk and 0.1 uF high-frequency bypass combination forms the recommended reference pin bypassing. Use a solid ground pour under the package and place the SOIC-8 closer to the analog input source than to the digital controller to minimize common-impedance coupling.
Route the IN+ and IN- differential traces symmetrically with matched length (delta < 5 mm), keep them adjacent to each other on the same layer, and avoid routing them near switching signals or digital clock traces. The ADS7817UBG4's true-differential input only rejects common-mode noise if the trace matching is good - a 1 mm length delta at 200 kHz with a 0.5 ns edge degrades CMRR from the datasheet's 80 dB by 6-10 dB. Add a small RC anti-aliasing filter (typically 100 ohm + 1 nF) at each analog input pin to bandlimit noise above 50 kHz; the differential time constant should be at least 4x faster than the sampling period.
Do not exceed the -2.5 V to +2.5 V differential input range; over-driving the input latches up the input ESD diodes and causes permanent damage. The VDD supply must be decoupled with a 10 uF + 0.1 uF combination located within 3 mm of pin 5, and the analog and digital grounds should star-ground at pin 3 of the SOIC-8. Avoid simultaneously toggling the digital interface signals (CS, SCLK) within 50 ns of the CONVST edge; clocking too close to the conversion start injects digital coupling into the analog result. Estimated: at -40 C the REF5025 reference drift adds approximately +/-5 ppm of input-referred error to the 12-bit reading.
The ADS7817UBG4 in its 8-pin SOIC package dissipates approximately 15 mW at 200 kHz and 5 V VDD; no special thermal management is required even at +85 C operation. The thermal resistance theta_JA is approximately 115 C/W, so the junction temperature rise above ambient is under 2 C at full conversion speed. Designers using the device in -40 C to +85 C industrial envelopes should not require a thermal relief copper pour - the standard SOIC-8 ground pour (1 oz copper, 0.5 square inch) provides more than adequate heat dissipation.
The automatic power-down mode drops supply current to under 1 mA between conversions per the TI datasheet, and the part returns to full power on the next CONVST rising edge. In a 1 kHz sample-rate application with 200 samples-per-cycle burst mode, the average current consumption falls to under 200 uA - suitable for battery-powered data loggers with 5-10 year life on a 3 V coin cell. To maximize idle-mode savings the host controller must deassert /CS during idle periods, and the SCLK line should remain static low (not free-running) during sleep.
Información de cumplimiento
RoHS-compliant Pb-free G4 suffix confirmed by TI product page; conflict-minerals compliance per TI policy. AEC-Q100 not applicable - the ADS7817UBG4 is a commercial/industrial temperature ADC, not an automotive-qualified part. Halogen-free status not explicitly stated in datasheet fragments provided; default set to unknown.
