MAX5025MAX5028 19-2239 Rev 2 3/09 500kHz, 36V Output, SOT23, PWM Step-Up DC-DC Converters General Description Features The MAX5025MAX5028 constant-frequency, pulse- Input Voltage Range: width modulating (PWM), low-noise boost converters 3V to 11V (MAX5026/MAX5028) are intended for low-voltage systems that often need a 4.5V to 11V (MAX5025/MAX5027) locally generated high voltage. These devices are Wide Output Voltage Range: V to 36V capable of generating low-noise, high output voltages CC required for varactor diode biasing in TV tuners, set-top Output Power: 120mW (max) boxes, and PCI cable modems. The MAX5025 User-Adjustable Output Voltage with MAX5028 operate from as low as 3V and switch at 500kHz. MAX5025/MAX5026 Using External Feedback Resistors The constant-frequency, current-mode PWM architec- ture provides for low output noise that is easy to filter. A Fixed 30V Output Voltage: MAX5027/MAX5028 40V lateral DMOS device is used as the internal power Internal 1.3 (typ), 40V Switch switch, making the devices ideal for boost converters up to 36V. The MAX5025/MAX5026 adjustable versions Constant PWM Frequency Provides Easy Filtering require the use of external feedback resistors to set the in Low-Noise Applications output voltage. The MAX5027/MAX5028 offer a fixed 500kHz (typ) Switching Frequency 30V output. These devices are available in a small, 6- pin SOT23 package. 1A (max) Shutdown Current Applications Small, 6-Pin SOT23 Package TV Tuner Power Supply Low-Noise Varactor Diode Biasing Ordering Information Set-Top Box Tuner Power Supply PART TEMP RANGE PIN-P ACKAG E PCI Cable Modem MAX5025EUT-T -40C to +85C 6 SOT23-6 Voice-Over-Cable MAX5026EUT-T -40C to +85C 6 SOT23-6 LCD Power Supply MAX5027EUT-T -40C to +85C 6 SOT23-6 Avalanche Photodiode Biasing MAX5028EUT-T -40C to +85C 6 SOT23-6 Typical Operating Circuit Selector Guide appears at end of data sheet. V = 4.5V TO 11V CC L1 (MAX5027) V = 3V TO 11V CC Pin Configuration D1 (MAX5028) V OUT V LX CC 30V TOP VIEW MAX5027 MAX5028 SHDN FB PGND16LX C1 C2 PGND MAX5025 GND 2 5V CC MAX5028 GND FB34 SHDN SOT23-6 Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE500kHz, 36V Output, SOT23, Step-Up DC-DC Converters ABSOLUTE MAXIMUM RATINGS V to GND............................................................-0.3V to +12V Operating Temperature Range ...........................-40C to +85C CC PGND to GND .......................................................-0.1V to +0.1V Continuous Power Dissipation (T = +70C) A FB to GND (MAX5025/MAX5026)...............-0.3V to (V + 0.3V) 6-Pin SOT23 (derate 8.7mW/C above +70C)..........695.7mW CC FB to GND (MAX5027/MAX5028)...........................-0.3V to +40V Junction Temperature......................................................+150C SHDN to GND.............................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +165C CC LX to GND ..............................................................-0.3V to +45V Lead Temperature (soldering 10s) ..................................+300C Peak LX Current................................................................600mA 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 = 5V, SHDN = V , T = -40C to +85C, unless otherwise noted. Typical values are at T = +25C.) (Note 1) CC CC A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUPPLY VOLTAGE MAX5026/MAX5028 3.0 11 Input Voltage Range V V CC MAX5025/MAX5027 4.5 11 Undervoltage Lockout V Rise/fall, hysteresis = 3mV 2.25 2.65 2.95 V UVLO MAX5025/MAX5026, FB = 1.4V Supply Current I 350 1000 A CC MAX5027/MAX5028, FB = 35V Shutdown Current I SHDN = GND 0.01 1A SHDN BOOST CONVERTER MAX5025/MAX5027 345 500 1000 Switching Frequency f kHz SW MAX5026/MAX5028, V = 3.3V 410 500 670 CC MAX5025/MAX5027, I = 2mA, V = 4.5V to 11V, 0.25 LOAD CC V = 30V OUT Line Regulation %/V MAX5026/MAX5028, I = 0.5mA, V = 3V to 11V, 0.25 LOAD CC V = 30V OUT MAX5025/MAX5027, V = 5V, I = 0 to 4mA, 2.0 CC LOAD V = 30V OUT Load Regulation % MAX5026/MAX5028, V = 3.3V, I = 0 to 1mA, 1.0 CC LOAD V = 30V OUT Thermal Shutdown 140 C Thermal Shutdown Hysteresis 2C 2 MAX5025MAX5028