Data SheetADN8835TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. 100100909080807070%)%)(60(60NCY50NCYE50EICIICIF40F40FFEE30302020LOAD = 2Ω10LOAD = 1Ω10VIN = 5VLOAD = 0.5ΩVIN = 3.3V0000.51.01.52.02.53.0 007 00.51.01.52.02.53.03.5 006 TEC CURRENT (A) 14174- TEC CURRENT (A) 14174- Figure 5. Efficiency vs. TEC Current at VIN = 3.3 V at Various Loads in Cooling Figure 8. Efficiency vs. TEC Current at VIN = 3.3 V and 5 V in Heating Mode Mode with 1 Ω Load 1003.0902.580A) (70NT2.0%) (60NCY50E1.5C CURRE EICITF40F EUM1.030IM AX M20LOAD = 2Ω0.5LOAD = 2Ω10LOAD = 1ΩLOAD = 1ΩLOAD = 0.5ΩLOAD = 0.5Ω0000.51.01.52.02.53.0 008 2.73.74.7 009 TEC CURRENT (A) 14174- INPUT VOLTAGE AT PVIN (V) 14174- Figure 6. Efficiency vs. TEC Current at VIN = 3.3 V at Various Loads in Heating Figure 9. Maximum TEC Current vs. Input Voltage at PVIN at Various Loads, Mode Without Voltage and Current Limit 1000.20900.15800.1070%)%)0.05(60R (NCY50E0RROICIEF40FFRE –0.05EV30–0.1020–0.1510VIN = 5VNO LOADVIN = 3.3V5mA LOAD0–0.2000.51.01.52.02.53.03.5 005 2.53.03.54.04.55.05.56.0 010 TEC CURRENT (A) 14174- SUPPLY VOLTAGE (V) 14174- Figure 7. Efficiency vs. TEC Current at VIN = 3.3 V and 5 V in Cooling Mode Figure 10. VREF Line Regulation with 1 Ω Load Rev. B | Page 9 of 27 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY DETAILED FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE MAXIMUM POWER DISSIPATION ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ANALOG PID CONTROL DIGITAL PID CONTROL POWERING THE CONTROLLER ENABLE AND SHUTDOWN OSCILLATOR CLOCK FREQUENCY External Clock Operation Connecting Multiple ADN8835 Devices TEMPERATURE LOCK INDICATOR SOFT START ON POWER-UP TEC VOLTAGE/CURRENT MONITOR Voltage Monitor Current Monitor MAXIMUM TEC VOLTAGE LIMIT Using a Resistor Divider to Set the TEC Voltage Limit MAXIMUM TEC CURRENT LIMIT Using a Resistor Divider to Set the TEC Current Limit APPLICATIONS INFORMATION SIGNAL FLOW THERMISTOR SETUP THERMISTOR AMPLIFIER (CHOPPER 1) PID COMPENSATION AMPLIFIER (CHOPPER 2) MOSFET DRIVER AMPLIFIERS PWM OUTPUT FILTER REQUIREMENTS Inductor Selection Capacitor Selection INPUT CAPACITOR SELECTION POWER DISSIPATION PWM Regulator Power Dissipation Conduction Loss (PCOND) Switching Losses (PSW) Transition Losses (PTRAN) Linear Regulator Power Dissipation THERMAL CONSIDERATION PCB LAYOUT GUIDELINES BLOCK DIAGRAMS AND SIGNAL FLOW GUIDELINES FOR REDUCING NOISE AND MINIMIZING POWER LOSS General PCB Layout Guidelines PWM Power Stage Layout Guidelines Linear Power Stage Layout Guidelines Placing the Thermistor Amplifier and PID Components EXAMPLE PCB LAYOUT USING TWO LAYERS OUTLINE DIMENSIONS ORDERING GUIDE