ADS7817UG4 - 12-Bit 200kSPS Differential ADC | Texas Instruments
MPN： ADS7817UG4 ✓ 啟用中ADS7817UG4 概覽
A SAR ADC is a successive-approximation-register analog-to-digital converter: it uses an internal DAC, a comparator, and a SAR logic block to perform a binary search against the input voltage, producing a digital output word in one conversion cycle. SAR ADCs sit in the broader hierarchy of analog-to-digital converters -> data converters -> mixed-signal ICs, offering an attractive middle ground between slow but precise delta-sigma ADCs and fast but power-hungry flash ADCs. The ADS7817UG4 specifically targets low-power, high-impedance, differential applications such as sensor signal chains and instrumentation front ends.
Differentiating features of the ADS7817UG4 include true differential input (rejecting common-mode noise in industrial environments), an automatic power-down mode that drops supply current between conversions, a serial (SPI/QSPI/MICROWIRE-compatible) interface, and 4.75 V to 5.25 V single-supply operation. Power dissipation is approximately 1.8 mW at 200 kSPS and falls to microwatt levels during power-down, making the part well suited to battery-powered or energy-harvesting data acquisition systems.
Architecturally, the device uses a charge-redistribution switched-capacitor DAC with a sample-and-hold front end, allowing direct connection to high-impedance sources without external buffering. The internal conversion clock is generated on-chip, so the only external clock needed is the serial interface clock. The differential input structure inherently rejects common-mode noise and is particularly useful when digitizing bridge sensors, thermocouples, or shunt currents in noisy industrial environments.
Typical applications include portable instrumentation, industrial process control loops, weigh scales, thermocouple and RTD front ends, battery monitoring systems, and isolated data acquisition modules. The wide input range and adjustable reference also make it a strong fit for transducer signal conditioning where dynamic range must be matched to the sensor output.
When designing with this ADC, pay attention to the reference bypass network and analog input common-mode voltage; place a 10 uF tantalum and 0.1 uF ceramic on REF and follow the recommended layout in the datasheet typical-application schematic. Use the CS/FSYNC pin for framing conversions and avoid driving AINP and AINN outside the input common-mode range, which can introduce distortion.
This page synthesizes distributor pricing, drop-in alternatives in the SOIC-8 footprint, and practical design notes that complement (but do not replace) the manufacturer datasheet.
直接替換替代品，適用於 ADS7817UG4 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： ADS7817UG4 （相同外形與佔位） — 差異在於 Architecture, Input-Referred Resolution, Package, Reference Voltage Range.
ADS7817UBG4
✅ 直接替換聯絡詢價
查看資料表 →ADS7817E/250
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7817UBG4
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →ADS7866IDBVR
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7867IDBVR
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7817UG4 最大額定值與電氣特性
| 解析度 | 12 bits |
| 取樣率 | 200 kSPS |
| Number of Channels | 1 |
| Input Type | True differential, bipolar |
| 輸入電壓範圍 | -2.5 V to +2.5 V (differential) |
| Reference Voltage Range | 100 mV to 2.5 V |
| Input-Referred Resolution | 49 uV to 1.22 mV (depending on VREF) |
| 供應電壓 | 4.75 V to 5.25 V |
| Supply Current (Power-Down) | Microwatt range (auto power-down between conversions) |
| 介面 | Serial (SPI/QSPI/MICROWIRE-compatible) |
| Architecture | Successive Approximation (SAR) with charge-redistribution CDAC |
| 工作溫度 | -40 C to +85 C |
| 封裝 | 8-pin SOIC (D) |
| Screening Level | Industrial |
| Pb-Free / RoHS | Yes (G4 green assembly) |
ADS7817UG4 腳位配置
| 腳位 1 | AINP — Positive analog input (differential) |
| 腳位 2 | AINN — Negative analog input (differential) |
| 腳位 3 | GND — Ground |
| 腳位 4 | REF — Reference voltage input (100 mV to 2.5 V) |
| 腳位 5 | VDD — Analog supply (4.75 V to 5.25 V) |
| 腳位 6 | GND — Ground |
| 腳位 7 | CS/FSYNC — Chip select / frame sync, active low |
| 腳位 8 | DOUT — Serial data output (MSB first) |
典型應用
ADS7817UG4 適用於 6 應用s: Weigh Scale Signal Chain, Portable Data Acquisition Module, Industrial Process Control Loop, Thermocouple and RTD Front End, Battery Monitoring System, Isolated Sensor Interface.
Weigh Scale Signal Chain
The ADS7817UG4 is well matched to load-cell and weigh-scale front ends where the 12-bit / 200 kSPS throughput resolves bridge outputs with milligram-class accuracy. Its true differential input rejects common-mode noise in industrial factory floors, while the adjustable 100 mV to 2.5 V reference lets the designer trade off input range against LSB size for the specific sensor sensitivity. The auto power-down mode keeps average current in the microwatt range for battery-powered scales. Connect the bridge output directly to AINP/AINN, place the 10 uF/0.1 uF reference bypass network on REF, and use the SPI interface to stream conversions into a microcontroller or host DSP. Compared to 24-bit delta-sigma ADCs, the ADS7817UG4 trades raw resolution for higher sample rate and lower latency.
推薦
Portable Data Acquisition Module
The ADS7817UG4's combination of 200 kSPS throughput, serial SPI interface, and auto power-down makes it a strong fit for handheld and battery-powered data loggers. The 5 V single-supply operation simplifies power-tree design, and the true-differential input allows direct connection to instrumentation signals without external op-amps. The 8-SOIC package footprint is hand-solderable, easing prototype iteration. Place the part in sleep mode between conversions to extend battery life to multi-month runtimes. The compact pinout leaves space on the PCB for an LC filter and an isolated front end. Designers should pay attention to the CS/FSYNC timing described in the TI datasheet to avoid bus contention on the DOUT line.
推薦
Industrial Process Control Loop
The ADS7817UG4 is suitable for 4-20 mA loop-derived voltage measurements, RTD front ends, and pressure-transducer signal chains inside industrial process-control modules. The true-differential input rejects common-mode noise injected by long sensor cables, and the 12-bit resolution is sufficient for many control loops where the actuator granularity is the limiting factor. The serial interface integrates easily with industrial microcontrollers and PLCs. Use the bipolar -2.5 V to +2.5 V input range to digitize bi-directional sensor outputs without extra signal conditioning. Industrial EMC immunity is supported by the SOIC-8 ground-pin arrangement, but designers should still place a TVS and a common-mode choke on the input lines for IEC 61000-4-2/4-4 immunity.
推薦
Thermocouple and RTD Front End
The ADS7817UG4 pairs well with thermocouple and RTD conditioning circuits in industrial temperature monitoring. The true differential input accommodates the low-level differential thermocouple voltage directly, while the adjustable reference lets the designer match the input range to the sensor output. At 200 kSPS the part oversamples the slow thermocouple signal, allowing digital averaging to extend effective resolution beyond 12 bits. The 5 V single-supply operation simplifies the cold-junction compensation circuit. Place a low-pass RC filter between the thermocouple amplifier output and the ADC input to limit aliasing. For higher accuracy, designers may stack two ADS7817UG4 units in parallel for redundant temperature sensing.
推薦
Battery Monitoring System
Battery management and fuel-gauge ICs in 5 V-tolerant battery packs can use the ADS7817UG4 to digitize cell voltages and pack-current shunts. The true-differential input measures the shunt directly without an instrumentation amplifier, while the bipolar -2.5 V to +2.5 V range supports charge and discharge current sensing. The auto power-down mode keeps the ADC quiescent when the pack is idle, extending runtime. The 8-SOIC footprint fits compactly inside a battery-management PCB. Designers should add input protection (TVS and PTC) and place the 10 uF/0.1 uF VDD bypass network close to the IC. The serial interface reports converted values to a host microcontroller, which applies SOC and SOH algorithms.
推薦
Isolated Sensor Interface
The ADS7817UG4 is well suited to isolated sensor modules where a 4-20 mA or 0-10 V transducer is galvanically isolated from the controller. Place the ADC on the sensor side, digitize the differential input, and send the serial data across an optocoupler or digital isolator. The 200 kSPS sample rate is more than sufficient for slow control loops, and the small SOIC-8 footprint leaves room for an isolated DC/DC. The auto power-down mode keeps the isolated power budget low. Designers should use a reinforced-rated isolator and follow the datasheet grounding and bypass recommendations to meet industrial safety standards such as IEC 61010. The 5 V single-supply operation simplifies the isolated power supply design.
推薦
推薦產品摘要
工程參考資料，適用於 ADS7817UG4 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | ADS7817UBG4 | ADS7817E/250 | ADS7817U | ADS7866IDBVR | ADS7867IDBVR |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC (wider body) | 8-SOIC |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS |
| Input Type | True differential | True differential | True differential | True differential | Pseudo-differential | Pseudo-differential (8 channels) |
| Input Voltage Range | -2.5 V to +2.5 V | -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 | 0 V to VREF |
| Reference Voltage | 100 mV to 2.5 V | 100 mV to 2.5 V | 100 mV to 2.5 V | 100 mV to 2.5 V | 0.1 V to VDD | 0.1 V to VDD |
| Supply Voltage | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| Channels | 1 | 1 | 1 | 1 | 1 | 8 |
| Interface | Serial SPI/QSPI/MICROWIRE | Serial SPI/QSPI/MICROWIRE | Serial SPI/QSPI/MICROWIRE | Serial SPI/QSPI/MICROWIRE | Serial SPI | Serial SPI |
主要差異化特點
- True differential input rejects common-mode noise (對比ADS7866IDBVR)
- Bipolar -2.5 V to +2.5 V input range (對比ADS7866IDBVR)
- Adjustable reference down to 100 mV (對比ADS7867IDBVR)
設計說明
Estimated: Decouple VDD with a 10 uF tantalum and a 0.1 uF ceramic placed within 2-3 mm of the VDD pin. Place the REF bypass capacitors (10 uF + 0.1 uF) as close to the REF pin as the SOIC-8 land pattern allows. Keep the analog input traces short and symmetric; route AINP and AINN as a differential pair with a continuous ground reference plane beneath to preserve 12-bit dynamic performance.
Do not drive the AINP/AINN analog inputs outside the recommended common-mode range or apply input transients before VDD is stable; either condition can corrupt conversions or latch up the input ESD cells. Tie CS/FSYNC high when the part is not in use, and avoid SCLK activity before VDD has stabilized. Refer to the TI ADS7817 datasheet timing diagrams for proper SPI framing of the 12-bit data word.
Place a single solid analog ground plane under the ADC and reference. Use a star-ground connection at the ADC GND pins, returning digital currents from the SPI bus and the microcontroller away from the analog ground. Guard the analog input traces with ground on both sides of the SOIC-8 footprint to minimize digital switching noise coupling through the substrate. A 1 kV or higher-rated TVS diode on the analog inputs is recommended for industrial installations subject to ESD or surge events.
合規資訊
G4 suffix denotes Pb-free green assembly. RoHS and REACH compliant per TI product page. Industrial temperature grade -40 C to +85 C, not AEC-Q100 automotive qualified.