EVALUATION KIT AVAILABLE MAX12900 Ultra-Low-Power 4-20mA Sensor Transmitter General Description Benefits and Features The MAX12900 is an ultra-low-power, highly integrated Wide Input Supply Range: 4.0V to 36V 4-20mA sensor transmitter. The MAX12900 integrates Ultra-Low-Power Consumption: 170A (typ) ten building blocks in a small package: a wide input supply High Linearity: 0.01% (Max Error) voltage LDO, two conditioner circuits for pulse-width- modulated (PWM) inputs, two low-power, low-drift, general- High Resolution: Up to 16 Bit purpose operational amplifiers (op amp) one wide bandwidth, Low Drift Voltage Reference: 10ppm/C max zero-offset drift operational amplifier two diagnostic Wide Temperature Range: -40C to +125C comparators, a power-up sequencer with power good Small Package: 5mm x 5mm x 0.8mm 32-pin TQFN output to allow for a smooth power-up, and a low-drift voltage reference. Applications The MAX12900 converts PWM data from a microcontroller Loop-Powered 4-20mA Current Transmitter into current over a 4-20mA loop with two, three, or four- Smart Sensors wire configurations. Remote Instrumentation The equivalent to an ultra-low-power, high-resolution, Industrial Automation and Process Control digital-to-analog converter is realized with the combination of two-PWM signals received from a microcontroller, the two conditioner circuits, and an active filter built with the integrated low-power op amp. The outputs of the two conditioner circuits provide a stable PWM amplitude over voltage supply and temperature variation. The wide band- width amplifier, in combination with a discrete transistor, Ordering Information appears at end of data sheet. converts a voltage input into a current output and allows HART and Foundation Fieldbus H1 signal modulation. The zero-offset operational amplifier and the low-drift voltage reference provide negligible error over wide temperature. The low-power operational amplifier and comparators provide building blocks for enhanced diagnostic features. Supply rail monitoring, output current readback, open circuit and failure detection are a few examples of diagnostic features. All these features, as well as ultra-low-power and high accuracy make the MAX12900 ideal for loop-powered smart sensor transmitters for industrial application. The MAX12900 is available in 5mm x 5mm 32-pin TQFN package and operates over a wide industrial temperature range of -40C to +125C. 19-100086 Rev 2 3/18MAX12900 Ultra-Low-Power 4-20mA Sensor Transmitter Functional Block Diagram VCCI VCCID VCC PWRGOOD VDD 1.2V VREF POWER-UP LDOFB SEQUENCER VCCI LDO VDD MAX12900 VCCI COMP2N COMP2O COMP2P VCCI VDD COMP1N COMP1O COMP1P COMPARATORS VCCI OP1N OP1O OP1 MAX12900 INTEGRATES 10 BUILDING BLOCKS: OP1P LDO POWER-UP SEQUENCER VCCI OP2N TWO COMPARATORS (COMP1, COMP2) OP2O TWO GENERAL PURPOSE OP AMPS (OP1, OP2) OP2 OP2P ONE LOW DRIFT OP AMP (OP3) 2.5V PRECISION REFERENCE VCCI TWO PWM RECEIVERS (PWMA, PWMB) OP3N OP3O OP3 OP3P OP-AMPS REFO VCCI VREF VCCI REFGND REFBUF 2.5V VREF VCCI 1V PWMAO PWMAP SHDN VCCI REFBUF 1V PWMBO PWMBP PWM EP SHDN Maxim Integrated 2 www.maximintegrated.com