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MAX11208

20-Bit, Single-Channel, Ultra-Low-Power,

Delta-Sigma ADC with 2-Wire Serial Interface

19-5246; Rev 0; 4/10

Ordering Information

Selector Guide

General Description

The MAX11208 is an ultra-low-power (< 300FA active

current), high-resolution, serial-output ADC. This device

provides the highest resolution per unit power in the

industry and is optimized for applications that require

very high dynamic range with low power, such as sen-

sors on a 4mA to 20mA industrial control loop. The

MAX11208 provides a high-accuracy internal oscillator

that requires no external components.

When used with the specified data rates, the internal

digital filter provides more than 80dB rejection of 50Hz or

60Hz line noise. The MAX11208 provides a simple 2-wire

serial interface in the space-saving, 10-pin FMAX

pack-

age. The MAX11208 operates over the -40NC to +85NC

temperature range.

Applications

Sensor Measurement (Temperature and

Pressure)

Portable Instrumentation

Battery Applications

Weigh Scales

Features

S 20-Bit Full-Scale Resolution

20-Bit Noise-Free Resolution at 13.75sps

19-Bit Noise-Free Resolution at 120sps

S 720nV

RMS

Noise (MAX11208B)

S 3ppm INL

S No Missing Codes

S Ultra-Low Power Dissipation

Operating Mode Current Drain < 300µA (max)

Sleep Mode Current Drain < 0.1µA

S 2.7V to 3.6V Analog Supply Voltage Range

S 1.7V to 3.6V Digital and I/O Supply Voltage Range

S Fully Differential Signal Inputs

S Fully Differential Reference Inputs

S Internal System Clock

2.4576MHz (MAX11208A)

2.2528MHz (MAX11208B)

S External Clock

S Serial 2-Wire Interface (Clock Input and Data

Output)

S On-Demand Offset and Gain Self-Calibration

S -40°C to +85°C Operating Temperature Range

S ±2kV ESD Protection

S Lead(Pb)-Free and RoHS-Compliant µMAX

Package

Note: All devices are specified over the -40NC to +85NC oper-

ating temperature range.

+Denotes a lead(Pb)-free/RoHS-compliant package.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

PART PIN-PACKAGE

OUTPUT RATE

(sps)

MAX11208AEUB+

10 FMAX

120

MAX11208BEUB+

10 FMAX

13.75

RESOLUTION

(BITS)

4-WIRE SPI, 16-PIN QSOP,

PROGRAMMABLE GAIN

4-WIRE SPI,

16-PIN QSOP

2-WIRE SERIAL,

10-PIN µMAX

24 MAX11210 MAX11200

MAX11201 (with buffers)

MAX11202 (without buffers)

20 MAX11206 MAX11207 MAX11208

18 MAX11209 MAX11211 MAX11212

16 MAX11213 MAX11203 MAX11205

Summary of content (14 pages)

PAGE 1
9-5246; Rev 0; 4/10 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface Features The MAX11208 is an ultra-low-power (< 300FA active current), high-resolution, serial-output ADC. This device provides the highest resolution per unit power in the industry and is optimized for applications that require very high dynamic range with low power, such as sensors on a 4mA to 20mA industrial control loop.
PAGE 2
MAX11208 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface ABSOLUTE MAXIMUM RATINGS Any Pin to GND.....................................................-0.3V to +3.9V AVDD to GND........................................................-0.3V to +3.9V DVDD to GND.......................................................-0.3V to +3.9V Analog Inputs (AINP, AINN, REFP, REFN) to GND ............................................. -0.3V to (VAVDD + 0.
PAGE 3
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface (VAVDD = +3.6V, VDVDD = +1.8V, VREFP - VREFN = VAVDD; internal clock, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC under normal conditions, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS REF Dynamic Input Current 7.
PAGE 4
MAX11208 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface ELECTRICAL CHARACTERISTICS (continued) (VAVDD = +3.6V, VDVDD = +1.8V, VREFP - VREFN = VAVDD; internal clock, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC under normal conditions, unless otherwise noted.
PAGE 5
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface TA = +85°C TA = +25°C 160 TA = -45°C 220 140 180 TA = +25°C 160 TA = -45°C 2.85 3.00 3.15 3.30 3.45 TA = +25°C 0 2.70 2.85 3.00 3.15 3.30 3.45 3.60 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 AVDD VOLTAGE (V) ACTIVE SUPPLY CURRENT vs. TEMPERATURE (MAX11208A) ACTIVE SUPPLY CURRENT vs. TEMPERATURE (MAX11208B) SLEEP CURRENT vs. TEMPERATURE (MAX11208A/MAX11208B) 250 0.8 VAVDD = 3.
PAGE 6
Typical Operating Characteristics (continued) (VAVDD = 3.6V, VDVDD = 1.8V, VREFP - VREFN = AVDD; internal clock; TA = TMIN to TMAX, unless otherwise specified. Typical values are at TA = +25NC.) 2.3 MAX11208B 1.0 0.5 TA = +85°C 0 2.2 TA = -45°C -1.0 2.70 3.00 3.15 3.30 3.45 1.5 2.0 2.5 3.0 3.5 4.0 -45 MAX11208 toc12 35 55 75 PSRR vs. FREQUENCY (MAX11208A) TA = +25°C 0 -2 -4 TA = -45°C -6 -8 8 +FS ERROR 6 0 -2.5 -2.0 -1.5 -1.0 -0.
PAGE 7
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface NORMAL MODE REJECTION OF 50Hz TO 60Hz (MAX11208B) NORMAL-MODE FREQUENCY RESPONSE (MAX11208B) -20 -20 -40 GAIN (dB) -40 GAIN (dB) MAX11208 toc20 0 MAX11208 toc19 0 -60 -80 -60 -80 -100 -100 -120 -120 -140 -140 10 1 100 40 1k 45 50 FREQUENCY (Hz) 55 60 65 70 FREQUENCY (Hz) Functional Diagram TIMING AVDD CLOCK GENERATOR CLK DIGITAL LOGIC AND SERIALINTERFACE CONTROLLER SCLK DVDD GND AINP AINN
PAGE 8
MAX11208 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface Pin Configuration TOP VIEW GND 1 10 CLK REFP 2 REFN 3 AINN 4 7 DVDD AINP 5 6 AVDD MAX11208 9 SCLK 8 RDY/DOUT µMAX Pin Description PIN NAME 1 GND Ground. Ground reference for analog and digital circuitry. 2 REFP Differential Reference Positive Input. REFP must be more positive than REFN. Connect REFP to a voltage between AVDD and GND. 3 REFN Differential Reference Negative Input.
PAGE 9
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface The MAX11208 is an ultra-low-power (< 240FA active), high-resolution, low-speed, serial-output ADC. This device provides the highest resolution per unit power in the industry and is optimized for applications that require very high dynamic range with low power, such as sensors on a 4mA to 20mA industrial control loop. The MAX11208 provides a high-accuracy internal oscillator, which requires no external components.
PAGE 10
MAX11208 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface The RDY/DOUT is used to signal data ready, as well as reading the data out when SCLK pulses are applied. RDY/DOUT is high by default. The MAX11208 pulls RDY/ DOUT low when data is available at the end of conversion, and stays low until clock pulses are applied at SCLK input; on applying the clock pulses at SCLK, the RDY/ DOUT outputs the conversion data on every SCLK positive edge.
PAGE 11
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface MAX11208 t1 t5 t2 SCLK 1 2 3 24 t3 t4 RDY/DOUT D18 D19 0 t6 CONVERSION IS DONE DATA IS AVAILABLE CONVERSION IS DONE DATA IS AVAILABLE t7 Figure 1. Timing Diagram for Data Read After Conversion SCLK 1 2 3 24 25 25TH SLK RISING EDGE PULLS RDY/DOUT HIGH RDY/DOUT D19 D18 0 CONVERSION IS DONE DATA IS AVAILABLE CONVERSION IS DONE DATA IS AVAILABLE Figure 2.
PAGE 12
MAX11208 20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface DEVICE ENTERS SLEEP MODE SCLK 1 2 3 DEVICE EXITS OUT SLEEP MODE 1 24 2 SLEEP MODE t9 t10 RDY/DOUT D18 D19 0 D19 CONVERSION IS DONE DATA IS AVAILABLE D18 CONVERSION IS DONE DATA IS AVAILABLE t11 Figure 4.
PAGE 13
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface See Figure 6 for the RTD temperature measurement circuit and Figure 7 for a resistive bridge measurement circuit. Chip Information PROCESS: BiCMOS IREF2 Package Information REFP IREF1 RREF REFN IREF1 = K x IREF2 MAX11208 AINP For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only.
PAGE 14
20-Bit, Single-Channel, Ultra-Low-Power, Delta-Sigma ADC with 2-Wire Serial Interface MAX11208 Revision History REVISION NUMBER REVISION_ DATE 0 4/10 DESCRIPTION Initial release PAGES_ CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.