MAX5021/MAX5022 19-2066 Rev 1 9/01 Current-Mode PWM Controllers for Isolated Power Supplies General Description Features The MAX5021/MAX5022 current-mode PWM controllers Available in a Tiny 6-Pin SOT23 Package contain all the control circuitry required for the design 50A Typical Startup Current of wide input voltage range isolated power supplies. These devices are well suited for use in universal input 1.2mA Typical Operating Current (85VAC to 265VAC) off-line or telecom (-36VDC to Large UVLO Hysteresis of 14V -72VDC) power supplies. Fixed Switching Frequency of 262kHz 12% An undervoltage lockout (UVLO) circuit with large hys- teresis coupled with low startup and operating current 50% Maximum Duty Cycle Limit (MAX5021) reduce power dissipation in the startup resistor and allow use of ceramic bypass capacitors. The 262kHz 75% Maximum Duty Cycle Limit (MAX5022) switching frequency is internally trimmed to 12% 60ns Cycle-by-Cycle Current-Limit Response accuracy this allows the optimization of the magnetic Time and filter components resulting in compact, cost-effec- tive power supplies. The MAX5021 with 50% maximum duty cycle and MAX5022 with 75% maximum duty Ordering Information cycle are recommended for forward converters and fly- back converters, respectively. The MAX5021/MAX5022 MAX are available in 6-pin SOT23, 8-pin MAX, and 8-pin TEMP. PIN- TOP DUTY PART DIP packages and are rated for operation over the RANGE PACKAGE MARK CYCLE -40C to +85C temperature range. MAX5021EUT 50% -40C to +85C 6 SOT23-6 AASQ Applications MAX5021EUA 50% -40C to +85C 8 MAX Universal Off-Line Power Supplies MAX5021EPA 50% -40C to +85C 8 PDIP Standby Power Supplies MAX5022EUT 75% -40C to +85C 6 SOT23-6 AASR Isolated Power Supplies MAX5022EUA 75% -40C to +85C 8 MAX Isolated Telecom Power Supplies MAX5022EPA 75% -40C to +85C 8 PDIP Mobile Phone Chargers WARNING: The MAX5021/MAX5022 are designed to work with high voltages. Exercise caution Typical Operating Circuit Pin Configuration V SUPPLY TOP VIEW V OUT OPTO 1 8 CS CS16 OPTO V 2 7 GND IN MAX5021 MAX5021 GND 2 5 V IN MAX5022 MAX5022 V V 3 6 NDRV IN CC V CC N.C. 4 5 N.C. MAX5021 NDRV34 V CC MAX5022 OPTO NDRV PDIP/ MAX SOT23 CS GND Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLECurrent-Mode PWM Controllers for Isolated Power Supplies ABSOLUTE MAXIMUM RATINGS V to GND .............................................................-0.3V to +30V 8-Pin MAX (derate 4.5mW/C above +70C) ..............362mW IN V to GND............................................................-0.3V to +13V 8-Pin PDIP (derate 9.1mW/C above +70C)................727mW CC NDRV to GND.............................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C CC CS, OPTO to GND....................................................-0.3V to +6V Storage Temperature Range .............................-55C to +150C NDRV Short-Circuit to GND........................................Continuous Lead Temperature (soldering 10s) ..................................+300C Continuous Power Dissipation (T = +70C) A 6-Pin SOT23 (derate 8.7mW/C above +70C).............696mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = +11V to +28V, V = 0, OPTO is unconnected, 10nF bypass capacitors at V and V , NDRV unconnected, T = -40C to IN CS IN CC A +85C, unless otherwise noted. Typical values are at V = +12V, T = +25C, unless otherwise noted.) (Note 1) IN A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS UNDERVOLTAGE LOCKOUT/STARTUP Undervoltage Lockout Wakeup V V rising 22 24 26 V UVR IN Level Undervoltage Lockout Shutdown V V falling 9.3 10 10.9 V UVF IN Level V Supply Current at Startup I V = +22V 50 85 A IN START IN V Range V 11 28 V IN IN T V steps up from +9V to +26V 5 Undervoltage Lockout UVR IN s Propagation Delay T V steps down from +26V to +9V 1 UVF IN INTERNAL SUPPLY V = +11V to +28V, sourcing 1A to 5mA IN V Regulator Set Point V 7.0 10.5 V CC CCSP from V CC V = +28V, OPTO connected to GND 0.9 2.43 IN V Supply Current after Startup I mA IN IN V = +28V, OPTO unconnected (Note 2) 0.4 IN GATE DRIVER R Measured at NDRV sinking 5mA 10 20 ON(LOW) Driver Output Impedance R Measured at NDRV sourcing 5mA 20 40 ON(HIGH) Driver Peak Sink Current I 250 mA SINK Driver Peak Source Current I 150 mA SOURCE PWM COMPARATOR Comparator Offset Voltage VO V - V 600 750 900 mV PWM OPTO CS CS Input Bias Current I -2 +2 A CS Propagation Delay from T 25mV overdrive 60 ns PWM Comparator Input to NDRV Minimum On-Time T 150 ns ON(MIN) CURRENT-LIMIT COMPARATOR Current-Limit Trip Threshold V 540 600 660 mV CS Current-Limit Propagation Delay T 25mV overdrive 60 ns CL from Comparator Input to NDRV 2 MAX5021/MAX5022