ADS816x 8-Channel, 16-Bit, 1MSPS, SAR ADC With Direct Sensor Interface

1 Features

Compact low-power data acquisition system:
- MUX breakout enables single external driver amplifier
- 16-bit SAR ADC
- Low-drift integrated reference and buffer
- 0.5 × V_REF output for analog input DC biasing
Excellent AC and DC performance:
- SNR: 92dB, THD: –110dB
- INL: ±0.3LSB, 16-bit no missing codes
Multiplexer with channel sequencer:
- Multiple channel-sequencing options:
  - Manual mode, on-the-fly mode, auto sequence mode, custom channel sequencing
- Fast response time with on-the-fly mode
System monitoring features:
- Per channel programmable window comparator
- False trigger avoidance with programmable hysteresis
Enhanced-SPI digital interface:
- 1MSPS throughput with 16MHz SCLK
- High-speed, 50MHz digital interface
Wide operating range:
- External V_REF input range: 2.5V to 5V
- AVDD from 3V to 5.5V
- DVDD from 1.65V to 5.5V
- –40°C to +125°C temperature range

2 Applications

3 Description

The ADS816x is a family of 16-bit, 8-channel, high-precision successive approximation register (SAR) analog-to-digital converters (ADCs). The ADCs operate from a single 5V supply with a 1MSPS (ADS8168), 500kSPS (ADS8167), and 250kSPS (ADS8166) total throughput.

The input multiplexer supports extended settling time, which makes driving the analog inputs easier. The output of the multiplexer and ADC analog inputs are available as device pins. This configuration allows one ADC driver op amp to be used for all eight analog inputs of the multiplexer.

The ADS816x features a digital window comparator with programmable high and low alarm thresholds per analog input channel. The single op-amp solution with programmable alarm thresholds enables low power, low cost, and smallest form-factor applications.

Package Information

PART NUMBER	PACKAGE⁽¹⁾	PACKAGE SIZE⁽²⁾
ADS816x	RHB (VQFN, 32)	5mm × 5mm

(1) For more information, see the Mechanical, Packaging, and Orderable Information.

(2) The package size (length × width) is a nominal value and includes pins, where applicable.

ADS816x Block Diagram

4 Pin Configuration and Functions

ADS8166 ADS8167 ADS8168 RHB Package,32-Pin VQFN(Top View)

Figure 4-1 RHB Package,32-Pin VQFN(Top View)

Table 4-1 Pin Functions

PIN		FUNCTION	DESCRIPTION
NAME	NO.	FUNCTION	DESCRIPTION
ADC-INM	20	Analog input	Negative ADC analog input.
ADC-INP	17	Analog input	Positive ADC analog input.
AIN0	9	Analog input	Analog input channel 0.
AIN1	10	Analog input	Analog input channel 1.
AIN2	11	Analog input	Analog input channel 2.
AIN3	12	Analog input	Analog input channel 3.
AIN4	13	Analog input	Analog input channel 4.
AIN5	14	Analog input	Analog input channel 5.
AIN6	15	Analog input	Analog input channel 6.
AIN7	16	Analog input	Analog input channel 7.
AIN-COM	8	Analog input	Common analog input.
ALERT	22	Digital output	Digital ALERT output; active high. This pin is the output of the logical OR of the enabled channel ALERTs.
AVDD	32	Power supply	Analog power-supply pin. Connect a 1µF capacitor from this pin to GND.
CS	23	Digital input	Chip-select input pin; active low. The device starts converting the active input channel on the rising edge of CS. The device takes control of the data bus when CS is low. The SDO-x pins go Hi-Z when CS is high.
DECAP	2	Power supply	Connect a 1µF capacitor to GND for the internal power supply.
DVDD	30	Power supply	Interface power-supply pin. Connect a 1µF capacitor from this pin to GND.
GND	1, 21, 31	Power supply	Ground.
MUXOUT-M	19	Analog output	MUX negative analog output.
MUXOUT-P	18	Analog output	MUX positive analog output.
READY	28	Digital output	Multifunction output pin. When CS is held high, READY reflects the device conversion status. READY is low when a conversion is in process. When CS is low, the status of READY depends on the output protocol selection.
REFby2	7	Analog output	The output voltage on this pin is equal to half the voltage on the REFP pin. Connect a 1µF capacitor from this pin to GND.
REFIO	3	Analog input/output	External reference voltage input; internal reference is a 4.096V output. Connect a 1µF capacitor from this pin to GND.
REFM	4	Analog input	Reference ground potential; short this pin to GND externally.
REFP	5, 6	Analog input/output	Reference buffer output, ADC reference input. Short pins 5 and 6 together.
RST	29	Digital input	Asynchronous reset input pin. A low pulse on the RST pin resets the device. All register bits return to the default states.
SCLK	25	Digital input	Clock input pin for the serial interface. All system-synchronous data transfer protocols are timed with respect to the SCLK signal.
SDI	24	Digital input	Serial data input pin. This pin transfers data or commands into the device.
SDO-0	26	Digital output	Serial communication pin: data output 0.
SDO-1/ SEQSTS	27	Digital output	Multifunction output pin. By default, this pin indicates the channel scanning status in the auto and custom channel sequence modes. In dual SDO data transfer mode, this pin functions as a serial communication pin: data output 1.
Thermal pad		Supply	Exposed thermal pad; connect to GND.