ADS869x 支持双极输入范围的 18 位 500kSPS 4 和 8 通道、单电源 SAR ADC
- ZHCSDW2 July 2015 ADS8694 , ADS8698
  
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ADS869x 支持双极输入范围的 18 位 500kSPS 4 和 8 通道、单电源 SAR ADC

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1 特性

具有集成模拟前端的 18 位模数转换器 (ADC)
具有自动和手动扫描功能的 4 通道、8 通道多路复用器
通道独立可编程输入：
- ±10.24V、±5.12V、±2.56V
- 10.24V、5.12V
5V 模拟电源：1.65V 到 5V I/O 电源
恒定的阻性输入阻抗：1MΩ
输入过压保护：高达 ±20V
低漂移的片上 4.096V 基准电压
出色的性能：
- 500kSPS 的总吞吐量
- 差分非线性 (DNL)：±0.5 最低有效位 (LSB)；最大积分非线性 (INL)：±1.5 LSB
- 增益误差和偏移误差的漂移均较低
- 信噪比 (SNR)：93.5dB；总谐波失真 (THD)：–105dB
- 低功耗：65mW
AUX 输入 → 直接连接到 ADC 输入
ALARM → 每通道的高低阈值
SPI™- 兼容接口，支持菊花链连接
工业温度范围：-40°C 至 125°C
TSSOP-38 封装 (9.7mm × 4.4mm)

框图

ADS8694 ADS8698 frontpage_ads8698_sbas686.gif

2 应用

电力自动化
保护中继器
PLC 模拟输入模块

3 说明

ADS8694 和 ADS8698 是基于 18 位逐次逼近寄存器 (SAR) 模数转换器 (ADC) 的 4 通道、8 通道集成数据采集系统，工作吞吐量达 500kSPS。这些器件提供了用于各输入通道的集成模拟前端电路（过压保护高达 ±20V）、支持自动和手动两种扫描模式的 4 通道或 8 通道多路复用器、以及低温度漂移的片上 4.096V 基准电压。这些器件由单个 5V 模拟电源供电，每个输入通道均可支持真正的双极输入范围（±10.24V、 ±5.12V 和 ±2.56V）和单极输入范围（0V 至 10.24V 以及 0V 至 5.12V）。模拟前端在所有输入范围内的增益均经过了精确调整，以确保高直流精度。输入范围的选择可通过软件进行编程，各通道输入范围的选择相互独立。该器件提供了一个 1MΩ 的恒定阻性输入阻抗（无论所选输入范围为何）。

ADS8694 和 ADS8698 为数字主机提供了一个兼容串行外设接口 (SPI) 的简单串行接口，同时支持以菊花链方式连接多个器件。数字电源可提供 1.65V 到 5.25V 范围内的电压，因此可直接连接各种主机控制器。

器件信息⁽¹⁾

器件型号	封装	封装尺寸（标称值）
ADS869x	TSSOP (38)	9.70mm x 4.40mm

要了解所有可用封装，请见数据表末尾的可订购米6体育平台手机版_好二三四附录。

增益误差与温度的关系曲线

4 修订历史记录

日期	修订版本	注释
2014 年 7 月	*	首次发布。

5 Device Comparison Table

PRODUCT	RESOLUTION (Bits)	CHANNELS	SAMPLE RATE (kSPS)
ADS8694	18	4, single-ended	500
ADS8698	18	8, single-ended	500

6 Pin Configuration and Functions

DBT Package

38-Pin TSSOP

Top View (Not to Scale)

ADS8694 ADS8698 po_ads8694_ads8698_sbas686.gif

Pin Functions

PIN			I/O	DESCRIPTION
NO.	NAME
NO.	ADS8694	ADS8698
1	SDI		Digital input	Data input for serial communication.
2	RST/PD		Digital input	Active low logic input. Dual functionality to reset or power-down the device.
3	DAISY		Digital input	Chain the data input during serial communication in daisy-chain mode.
4	REFSEL		Digital input	Active low logic input to enable the internal reference. When low, the internal reference is enabled; REFIO becomes an output that includes the V_REF voltage. When high, the internal reference is disabled; REFIO becomes an input to apply the external V_REF voltage.
5	REFIO		Analog input, output	Internal reference output and external reference input pin. Decouple with REFGND on pin 6.
6	REFGND		Power supply	Reference GND pin; short to the analog GND plane. Decouple with REFIO on pin 5 and REFCAP on pin 7.
7	REFCAP		Analog output	ADC reference decoupling capacitor pin. Decouple with REFGND on pin 6.
8	AGND		Power supply	Analog ground pin. Decouple with AVDD on pin 9.
9	AVDD		Power supply	Analog supply pin. Decouple with AGND on pin 8.
10	AUX_IN		Analog input	Auxiliary input channel: positive input. Decouple with AUX_GND on pin 11.
11	AUX_GND		Analog input	Auxiliary input channel: negative input. Decouple with AUX_IN on pin 10.
12	NC	AIN_6P	Analog input	Analog input channel 6, positive input. Decouple with AIN_6GND on pin 13. No connection for the ADS8694; this pin can be left floating or connected to AGND.
13	NC	AIN_6GND	Analog input	Analog input channel 6, negative input. Decouple with AIN_6P on pin 12. No connection for the ADS8694; this pin can be left floating or connected to AGND.
14	NC	AIN_7P	Analog input	Analog input channel 7, positive input. Decouple with AIN_7GND on pin 15. No connection for the ADS8694; this pin can be left floating or connected to AGND.
15	NC	AIN_7GND	Analog input	Analog input channel 7, negative input. Decouple with AIN_7P on pin 14. No connection for the ; this pin can be left floating or connected to AGND.
16	AIN_0P		Analog input	Analog input channel 0, positive input. Decouple with AIN_0GND on pin 17.
17	AIN_0GND		Analog input	Analog input channel 0, negative input. Decouple with AIN_0P on pin 16.
18	AIN_1P		Analog input	Analog input channel 1, positive input. Decouple with AIN_1GND on pin 19.
19	AIN_1GND		Analog input	Analog input channel 1, negative input. Decouple with AIN_1P on pin 18.
20	AIN2_GND		Analog input	Analog input channel 2, negative input. Decouple with AIN_2P on pin 21.
21	AIN_2P		Analog input	Analog input channel 2, positive input. Decouple with AIN_2GND on pin 20.
22	AIN_3GND		Analog input	Analog input channel 3, negative input. Decouple with AIN_3P on pin 23.
23	AIN_3P		Analog input	Analog input channel 3, positive input. Decouple with AIN_3GND on pin 22.
24	NC	AIN_4GND	Analog input	Analog input channel 4, negative input. Decouple with AIN_4P on pin 25. No connection for the ADS8694; this pin can be left floating or connected to AGND.
25	NC	AIN_4P	Analog input	Analog input channel 4, positive input. Decouple with AIN_4GND on pin 24. No connection for the ADS8694; this pin can be left floating or connected to AGND.
26	NC	AIN_5GND	Analog input	Analog input channel 5, negative input. Decouple with AIN_5P on pin 27. No connection for the ADS8694; this pin can be left floating or connected to AGND.
27	NC	AIN_5P	Analog input	Analog input channel 5, positive input. Decouple with AIN_5GND on pin 26. No connection for the ADS8694; this pin can be left floating or connected to AGND.
28	AGND		Power supply	Analog ground pin
29	AGND		Power supply	Analog ground pin
30	AVDD		Power supply	Analog supply pin. Decouple with AGND on pin 31.
31	AGND		Power supply	Analog ground pin. Decouple with AVDD on pin 30.
32	AGND		Power supply	Analog ground pin
33	DGND		Power supply	Digital ground pin. Decouple with DVDD on pin 34.
34	DVDD		Power supply	Digital supply pin. Decouple with DGND on pin 33.
35	ALARM		Digital output	Active high alarm output
36	SDO		Digital output	Data output for serial communication
37	SCLK		Digital input	Clock input for serial communication
38	CS		Digital input	Active low logic input; chip-select signal