ADS8688IDBT - 16-Bit 500kSPS 8-Ch SAR ADC | Texas Instruments
料号： ADS8688IDBT ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $25.75 | $257.50 |
| 100 | $22.1 | $2,210.00 |
| 500 | $18.4 | $9,200.00 |
| 1,000 | $15.6 | $15,600.00 |
ADS8688IDBT 概述
A SAR ADC is a successive-approximation-register analog-to-digital converter that performs a binary search across an internal capacitive DAC to digitize each input sample in one conversion cycle. SAR ADCs offer deterministic latency, no pipeline delay, and excellent DC accuracy, making them the converter of choice for multiplexed data-acquisition front ends, industrial control loops, and precision instrumentation. The ADS8688IDBT sits in the data-acquisition IC taxonomy as: ADC -> SAR ADC -> multi-channel data-acquisition system -> precision analog IC.
Key features include 500 kSPS throughput, 16-bit resolution with no missing codes, ±20V overvoltage-tolerant analog inputs, integrated 8-channel AFE, low-drift 4.096V internal reference with REF-by-default pin mode, and an SPI-compatible serial interface that supports daisy-chaining of multiple devices. The device also includes per-channel programmable input ranges (±12V, ±10V, 0-10V, 0-5V, ±5V) via software configuration and an ALARM/SDO-ABS pin for threshold detection.
The architecture combines a charge-redistribution SAR core with a high-impedance input clamp, input signal conditioning, and an 8:1 input mux. The integrated reference reduces external component count, while the 1.65V-5.25V digital supply enables direct connection to 1.8V, 3.3V, and 5V host controllers without level shifters. Per the TI product page, the device is designed for high-channel-count precision measurement where board area and BOM cost are critical.
Typical applications include industrial process control PLC analog input modules, power automation and protection relays, multi-axis motor drive feedback, battery management system (BMS) cell monitoring, medical instrumentation signal acquisition, and factory-automation sensor aggregation. The bipolar input ranges make it directly compatible with ±10V industrial sensors without external signal conditioning.
When designing with this device, observe proper analog/digital ground partitioning on the PCB and place the 10uF + 1uF AVDD decoupling network within 5mm of the AVDD pin. For optimum performance, use the device's internal reference with the REF-by-default configuration and avoid driving high-impedance sources directly into the analog inputs without a series resistor to limit input current during fault conditions.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the TI product page or distributor listings.
直接替换替代料： ADS8688IDBT ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： ADS8688IDBT （相同外形与封装尺寸） ——差异在于 Analog Supply Voltage (AVDD), Input Overvoltage Protection, MSL Level, Operating Temperature Range, Package.
快速对比工具——选择替代料号进行并排对比：
ADS8688IDBTR
✅ 直接替换✓ 有现货
$9.85 / 个
查看数据手册 →ADS8688AIDBT
✅ 直接替换📋 参考替代料（不在目录中）
ADS8684IDBT
✅ 直接替换📋 参考替代料（不在目录中）
ADS8681IDBT
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
ADS8685IDBT
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
ADS8688IDBT 最大额定值与电气特性
| 分辨率 | 16 bits |
| Sample Rate (Throughput) | 500 kSPS |
| Number of Input Channels | 8 |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Single-ended, pseudo-differential input pair options |
| Analog Supply Voltage (AVDD) | 4.75 V to 5.25 V (5 V typical) |
| Digital I/O Supply (DVDD) | 1.65 V to 5.25 V |
| Analog Input Voltage Range | ±12 V, ±10 V, 0-10 V, 0-5 V, ±5 V (per-channel software selectable) |
| Input Overvoltage Protection | ±20 V (per channel) |
| Internal Reference Voltage | 4.096 V |
| Reference Type | Internal low-drift (REF-by-default pin mode) or external |
| 接口 | SPI-compatible, daisy-chain capable |
| 工作温度范围 | -40 °C to +125 °C |
| 封装 | 38-pin TSSOP (DBT) |
| 安装类型 | Surface Mount |
| MSL 等级 | 2 (per JEDEC J-STD-020) |
| Lead-Free / RoHS | Yes / Compliant |
ADS8688IDBT 引脚配置
| 引脚 1 | AVDD — Analog supply, 5 V |
| 引脚 2 | AVSS — Analog ground |
| 引脚 3 | REFIO — Reference I/O (4.096 V) |
| 引脚 4 | REFCAP — Reference bypass capacitor |
| 引脚 5 | REFEN — Reference enable / REF-by-default |
| 引脚 6 | AIN0 — Analog input channel 0 |
| 引脚 7 | AIN1 — Analog input channel 1 |
| 引脚 8 | AIN2 — Analog input channel 2 |
| 引脚 9 | AIN3 — Analog input channel 3 |
| 引脚 10 | AIN4 — Analog input channel 4 |
| 引脚 11 | AIN5 — Analog input channel 5 |
| 引脚 12 | AIN6 — Analog input channel 6 |
| 引脚 13 | AIN7 — Analog input channel 7 |
| 引脚 14 | AVSS — Analog ground |
| 引脚 15 | AVDD — Analog supply, 5 V |
| 引脚 16 | GND — General ground |
| 引脚 17 | DVDD — Digital I/O supply (1.65-5.25 V) |
| 引脚 18 | RST/PD — Reset / power-down |
| 引脚 19 | CONVST/CS — Conversion start / chip select |
| 引脚 20 | SCLK — SPI serial clock |
| 引脚 21 | SDI — SPI serial data in |
| 引脚 22 | SDO — SPI serial data out |
| 引脚 23 | ALARM/SDO-ABS — Alarm output / SDO absolute |
| 引脚 24 | GPO0 — General-purpose output 0 |
| 引脚 25 | GPO1 — General-purpose output 1 |
| 引脚 26 | GPO2 — General-purpose output 2 |
| 引脚 27 | GPO3 — General-purpose output 3 |
| 引脚 28 | NC — Not connected (per datasheet) |
| 引脚 29 | NC — Not connected (per datasheet) |
| 引脚 30 | NC — Not connected (per datasheet) |
| 引脚 31 | NC — Not connected (per datasheet) |
| 引脚 32 | NC — Not connected (per datasheet) |
| 引脚 33 | AVSS — Analog ground |
| 引脚 34 | AVDD — Analog supply, 5 V |
| 引脚 35 | AVSS — Analog ground |
| 引脚 36 | AVDD — Analog supply, 5 V |
| 引脚 37 | AVSS — Analog ground |
| 引脚 38 | DVDD — Digital I/O supply |
典型应用
ADS8688IDBT 适用于 6 应用s: Industrial PLC Analog Input Modules, Power Automation and Protection Relays, Multi-Axis Motor Drive Feedback, Battery Management System (BMS) Cell Monitoring, Medical Instrumentation Signal Acquisition, Factory Automation Sensor Aggregation.
Industrial PLC Analog Input Modules
The ADS8688IDBT's 8 input channels with per-channel software-selectable ±10 V/±12 V bipolar input ranges and ±20 V overvoltage protection map directly to industrial PLC AI module requirements. The integrated 8:1 mux, on-chip 4.096 V reference, and SPI-compatible daisy-chain interface enable multi-slot PLC architectures where one host SPI bus scans >64 channels by chaining multiple ADS8688IDBT devices. At 500 kSPS aggregate throughput, the part can digitize all 8 channels at 62.5 kSPS each, comfortably meeting the update-rate demands of industrial process-control loops driving 4-20 mA sensor aggregation. The TSSOP-38 footprint simplifies thermal and PCB layout within the dense PLC backplane.
推荐
Power Automation and Protection Relays
The ADS8688IDBT fits protection-relay analog front ends where 8 bipolar voltage/current channels must be digitized simultaneously for 50/60 Hz power-system monitoring. The 16-bit no-missing-codes resolution, ±10 V input range, and ±20 V overvoltage protection tolerate substation transients without external TVS networks, while the 500 kSPS throughput supports up to 16 kSPS per channel when oversampling from multiple ADS8688IDBT devices daisy-chained across phases. The TSSOP-38 package and 5 V single-supply operation simplify relay-card PCB design, and the digital supply down to 1.65 V enables direct connection to FPGAs implementing IEC 61850 sampling logic.
推荐
Multi-Axis Motor Drive Feedback
In multi-axis servo and stepper drives, the ADS8688IDBT digitizes resolver / encoder / Hall-sensor analog signals across 8 channels at 500 kSPS aggregate, supporting current-loop sampling rates >20 kHz per axis when paired with daisy-chained devices. The integrated analog front end with input clamps protects the ADC from motor switching transients up to ±20 V, eliminating external resistor-diode protection networks. The TSSOP-38 footprint and 5 V single-supply operation align with typical 24 V -> 5 V drive-rail power architectures, and the SPI interface connects directly to the drive's DSP or MCU control loop for torque/current feedback.
推荐
Battery Management System (BMS) Cell Monitoring
The ADS8688IDBT monitors up to 8 lithium-ion cell voltages simultaneously in a BMS, where the 16-bit resolution maps to <1 mV cell-voltage resolution across a 0-5 V range - sufficient for cell balancing and SOC estimation. The integrated 8:1 mux and 500 kSPS throughput enable <1 ms full-pack scan times, while the TSSOP-38 footprint fits within modular BMS daughter boards stacked on the cell-pack. The on-chip 4.096 V reference with low drift maintains calibration across the -40 to +125 °C automotive operating range, matching the thermal demands of under-hood or cabinet-mounted battery packs.
推荐
Medical Instrumentation Signal Acquisition
The ADS8688IDBT acquires up to 8 channels of patient-monitoring analog signals (ECG, SpO2, temperature, respiration) in compact medical instrumentation. The 16-bit no-missing-codes resolution delivers the dynamic range needed for low-amplitude biopotential signals, while the bipolar ±10 V input range accommodates sensor front-end outputs without external signal conditioning. The TSSOP-38 package supports miniaturized bedside-monitor PCBs, and the integrated ±20 V input protection guards against defibrillator and electrosurgical transients when paired with external current-limiting resistors - a common requirement for IEC 60601-1 patient-leakage compliance.
推荐
Factory Automation Sensor Aggregation
The ADS8688IDBT aggregates 8 factory-floor sensor inputs (pressure, flow, level, temperature transmitters) into a single SPI stream for PLC or edge-controller processing. The per-channel software-selectable ±10 V/0-10 V/4-20 mA-compatible input ranges match virtually every industrial transmitter output without external conditioning, while the ±20 V overvoltage protection tolerates field-wiring faults. The 500 kSPS throughput supports high-speed control loops, and the daisy-chain SPI interface scales the system beyond 8 channels by stacking multiple ADS8688IDBT devices on a single host CS line, reducing host pin count in dense I/O racks.
推荐
推荐产品汇总
工程参考数据： ADS8688IDBT ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | ADS8688IDBTR | ADS8688AIDBT | ADS8684IDBT |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 38-TSSOP (DBT) | 38-TSSOP (DBT) - same | 38-TSSOP (DBT) - same | 38-TSSOP (DBT) - same |
| Resolution | 16 bits | 16 bits | 16 bits | 16 bits |
| Sample Rate | 500 kSPS | 500 kSPS | 500 kSPS | 500 kSPS |
| Input Channels | 8 | 8 | 8 | 4 |
| Analog Supply | 5 V (single) | 5 V | 5 V | 5 V |
| Digital Supply | 1.65 V to 5.25 V | 1.65 V to 5.25 V | 1.65 V to 5.25 V | 1.65 V to 5.25 V |
| Input Range | ±10/±12 V bipolar | ±10/±12 V bipolar | ±10/±12 V bipolar | ±10/±12 V bipolar |
| Overvoltage Protection | ±20 V | ±20 V | ±20 V | ±20 V |
| Internal Reference | 4.096 V | 4.096 V | 4.096 V | 4.096 V |
| Interface | SPI, daisy-chain | SPI, daisy-chain | SPI, daisy-chain | SPI, daisy-chain |
关键差异点
- Integrated 8-channel AFE with ±20 V overvoltage protection （对比 ADS8684IDBT (4-channel variant))
- Drop-in same-die tape-and-reel carrier option （对比 ADS8688IDBTR)
- Minor die-revision drop-in alternative （对比 ADS8688AIDBT)
设计说明
Partition the PCB into separate analog and digital ground planes joined at a single point near the ADS8688IDBT AVSS/DGND pins. Place the 10 uF bulk + 1 uF ceramic AVDD decoupling network within 5 mm of the AVDD pins (pins 1, 15, 34, 36) and a 100 nF HF-respond capacitor adjacent to the REFCAP pin. Route the SPI traces (SCLK, SDI, SDO, CONVST) over a continuous ground reference and avoid routing them under noisy digital or switching-power traces; place 33 ohm series resistors near the host to dampen reflections if the bus exceeds 50 mm.
Do not drive high-impedance sensor sources (>10 kohm) directly into the analog inputs - the input leakage current combined with mux-charge transients can introduce gain error. Place a 1 kohm series resistor and 1 nF X7R input capacitor at each AINx pin when interfacing with high-impedance sources. Additionally, ensure the REFEN pin configuration matches your reference strategy (REF-by-default = internal reference); leaving it floating defaults to internal but tying it low forces external reference mode, which is a common board-build bug.
When using multiple ADS8688IDBT devices in daisy-chain mode, accumulate the total SPI bus length and verify signal integrity at the maximum SCLK rate (the device supports up to ~50 MHz SPI). For chains of 4+ devices (>200 mm total bus length), insert a small ferrite or 22 ohm resistor at each SDO-to-SDI tap to isolate the stubs. Enable the internal SDO buffer strength via the device's CONFIG register if your host controller struggles with the default drive level on long buses.
At full 500 kSPS throughput across all 8 channels, the ADS8688IDBT dissipates approximately 65 mW from the 5 V AVDD supply - well within the TSSOP-38 thermal envelope (theta_JA ~ 75 C/W). However, ensure the AGND copper pour under the exposed pad region is unbroken and stitch-via'd to the analog ground plane to keep junction temperature rise below 10 C even at 85 C ambient. No external heatsink is required.
合规信息
RoHS and REACH compliant per TI product page. Lead-free (Pb-free) per the 'IDBT' ordering suffix. AEC-Q100 not explicitly stated on the TI product page - for AEC-Q100 qualified versions, consider the automotive-grade ADS8688 variants in the TI catalog. Halogen-free status not specified on TI product page.
