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18-Bit, Single-Channel, Ultra-Low-Power, Delta-

Sigma ADCs with Programmable Gain and GPIO

Pin Description

Pin Configuration

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

GPIO1

GPIO4

CLK

SCLK

RDY/DOUT

DIN

CS

DVDD

AVDD

TOP VIEW

QSOP

GPIO2

GPIO3

REFN

GND

REFP

AINN

AINP

+

MAX11209

MAX11211

PIN

NAME

FUNCTION

1

GPIO1

General-Purpose I/O 1. Register controllable using SPI.

2

GPIO2

General-Purpose I/O 2. Register controllable using SPI.

3

GPIO3

General-Purpose I/O 3. Register controllable using SPI.

4

GND

Ground. Ground reference for analog and digital circuitry.

5

REFP

Differential Reference Positive Input. REFP must be more positive than REFN. Connect REFP to a voltage

between AVDD and GND.

6

REFN

Differential Reference Negative Input. REFN must be more negative than REFP. Connect REFN to a volt-

age between AVDD and GND.

7

AINN

Negative Fully Differential Analog Input

8

AINP

Positive Fully Differential Analog Input

9

AVDD

Analog Supply Voltage. Connect a supply voltage between +2.7V and +3.6V with respect to GND.

10

DVDD

Digital Supply Voltage. Connect a digital supply voltage between +1.7V and +3.6V with respect to GND.

11

CS

Active-Low, Chip-Select Logic Input

12

DIN

Serial-Data Input. Data present at DIN is shifted to the device’s internal registers at the rising edge of the

serial clock at SCLK, when the device is accessed for an internal register write or for a command opera-

tion.

13

RDY/DOUT

Data Ready Output/Serial-Data Output. This output serves a dual function. In addition to the serial-data

output function, the RDY/DOUT also indicates that the data is ready when the RDY is logic-low. RDY/

DOUT changes on the falling edge of SCLK.

14

SCLK

Serial-Clock Input. Apply an external serial clock to SCLK.

15

CLK

External Clock Signal Input. When external clock mode is selected (EXTCLK = 1), provide a 2.4576MHz

or 2.048MHz clock signal at CLK. Other frequencies can be used, but the data rate and digital filter

notch frequencies scale accordingly.

16

GPIO4

General-Purpose I/O 4. Register controllable using SPI.