Overview
The ADS8691IPW, produced by Texas Instruments, is a high-speed, high-precision 18-bit successive approximation (SAR) analog-to-digital converter (ADC) integrated into a data acquisition system. This device features an integrated analog front-end (AFE) input driver circuit, overvoltage protection up to ±20 V, and an on-chip 4.096-V reference with extremely low temperature drift. It operates on a single 5-V analog supply and supports both bipolar and unipolar input ranges, making it versatile for various applications. The ADS8691IPW is part of the ADS8691, ADS8695, and ADS8699 family, with the ADS8691 model specifically offering a sampling rate of 1 MSPS.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Resolution | 18 Bits | |
| Sampling Rate | 1 MSPS | |
| Input Ranges (Bipolar) | ±12.288 V, ±10.24 V, ±6.144 V, ±5.12 V, ±2.56 V | V |
| Input Ranges (Unipolar) | 0 V–12.288 V, 0 V–10.24 V, 0 V–6.144 V, 0 V–5.12 V | V |
| Analog Supply Voltage | 4.75 to 5.25 V | V |
| Digital Supply Voltage | 1.65 to 3.3 V | V |
| Input Overvoltage Protection | Up to ±20 V | V |
| On-chip Reference Voltage | 4.096 V | V |
| Differential Nonlinearity (DNL) | ±0.6 LSB | LSB |
| Integral Nonlinearity (INL) | ±1.75 LSB | LSB |
| Signal-to-Noise Ratio (SNR) | 92.5 dB | dB |
| Total Harmonic Distortion (THD) | –110 dB | dB |
| Operating Temperature Range | –40°C to +125°C | °C |
| Package Type | TSSOP (16 pins) |
Key Features
- 18-bit SAR ADC with integrated analog front-end (AFE) input driver circuit
- High-speed sampling rate of 1 MSPS for the ADS8691 model
- Software programmable input ranges: bipolar (±12.288 V, ±10.24 V, ±6.144 V, ±5.12 V, ±2.56 V) and unipolar (0 V–12.288 V, 0 V–10.24 V, 0 V–6.144 V, 0 V–5.12 V)
- Constant resistive input impedance ≥ 1 MΩ
- Input overvoltage protection up to ±20 V
- On-chip 4.096-V reference with low temperature drift
- Excellent performance: DNL ±0.6 LSB, INL ±1.75 LSB, SNR 92.5 dB, THD –110 dB
- ALARM feature with high and low threshold settings
- multiSPI™ digital interface with daisy-chain capability, backward-compatible to traditional SPI protocol
- Extended industrial temperature range: –40°C to +125°C
Applications
- Analog input modules
- Data acquisition (DAQ) systems
- Semiconductor testing
- LCD testing
Q & A
- What is the resolution of the ADS8691IPW ADC?
The ADS8691IPW has a resolution of 18 bits.
- What are the sampling rates for the ADS8691, ADS8695, and ADS8699 models?
The sampling rates are 1 MSPS for the ADS8691, 500 kSPS for the ADS8695, and 100 kSPS for the ADS8699.
- What are the input voltage ranges supported by the ADS8691IPW?
The device supports bipolar ranges of ±12.288 V, ±10.24 V, ±6.144 V, ±5.12 V, and ±2.56 V, as well as unipolar ranges of 0 V–12.288 V, 0 V–10.24 V, 0 V–6.144 V, and 0 V–5.12 V.
- What is the input overvoltage protection limit of the ADS8691IPW?
The input overvoltage protection is up to ±20 V.
- What is the on-chip reference voltage and its temperature drift?
The on-chip reference voltage is 4.096 V with a temperature drift of 4 to 7 ppm/°C.
- What is the operating temperature range of the ADS8691IPW?
The operating temperature range is –40°C to +125°C.
- What type of digital interface does the ADS8691IPW use?
The device uses a multiSPI™ digital interface that is backward-compatible to the traditional SPI protocol.
- What are the power supply requirements for the ADS8691IPW?
The analog supply voltage is 4.75 to 5.25 V, and the digital supply voltage is 1.65 to 3.3 V.
- What are some typical applications of the ADS8691IPW?
Typical applications include analog input modules, data acquisition systems, semiconductor testing, and LCD testing.
- What is the package type of the ADS8691IPW?
The device is packaged in a TSSOP (16 pins) package.
