MAX730A/MAX738A/MAX744A 19-0165 Rev 2 1/96 5V, Step-Down, Current-Mode PWM DC-DC Converters General Description Features The MAX730A/MAX738A/MAX744A are 5V-output 750mA Load Currents (MAX738A/MAX744A) CMOS, step-down switching regulators. The MAX738A/ High-Frequency, Current-Mode PWM MAX744A accept inputs from 6V to 16V and deliver 750mA. The MAX744A guarantees 500mA load capa- 159kHz to 212.5kHz Guaranteed Oscillator bility for inputs above 6V and has tighter oscillator fre- Frequency Limits (MAX744A) quency limits for low-noise (radio) applications. The 85% to 96% Efficiencies MAX730A accepts inputs between 5.2V and 11V and delivers 450mA for inputs above 6V. Typical efficien- 1.7mA Quiescent Current cies are 85% to 96%. Quiescent supply current is 6A Shutdown Supply Current 1.7mA and only 6A in shutdown. Pulse-width modulation (PWM) current-mode control Single Preselected Inductor Value, provides precise output regulation and excellent tran- No Component Design Required sient responses. Output voltage accuracy is guaran- Overcurrent, Soft-Start, and Undervoltage teed to be 5% over line, load, and temperature varia- tions. Fixed-frequency switching allows easy filtering of Lockout Protection output ripple and noise, as well as the use of small Cycle-by-Cycle Current Limiting external components. These regulators require only a 8-Pin DIP/SO Packages (MAX730A) single inductor value to work in most applications, so no inductor design is necessary. Ordering Information The MAX730A/MAX738A/MAX744A also feature cycle- by-cycle current limiting, overcurrent limiting, undervolt- PART TEMP. RANGE PIN-PACKAGE age lockout, and programmable soft-start protection. MAX730ACPA 0C to +70C 8 Plastic DIP MAX730ACSA 0C to +70C 8 SO Applications MAX730AC/D 0C to +70C Dice* Portable Instruments MAX730AEPA -40C to +85C 8 Plastic DIP Cellular Phones and Radios MAX730AESA -40C to +85C 8 SO MAX730AMJA -55C to +125C 8 CERDIP Personal Communicators Ordering Information continued at end of data sheet. Distributed Power Systems *Contact factory for dice specifications. Computer Peripherals Pin Configurations Typical Operating Circuit INPUT 6V TO 16V TOP VIEW OUTPUT 33H V+ 5V 68F LX SHDN 1 8 V+ 100F MAX738A REF 2 LX 7 MAX744A MAX730A ON/OFF SHDN OUT SS 3 GND 6 MAX738A MAX744A 4 OUT CC 5 REF CC DIP SS GND Pin Configurations continued on last page. Maxim Integrated Products 1 For free samples & the latest literature: 5V, Step-Down, Current-Mode PWM DC-DC Converters ABSOLUTE MAXIMUM RATINGS Pin Voltages Operating Temperature Ranges: V+ (MAX730A)......................................................+12V, -0.3V MAX7 AC ....................................................0C to +70C V+ (MAX738A/MAX744A).....................................+18V, -0.3V MAX7 AE .................................................-40C to +85C LX (MAX730A) .................................(V+ - 12V) to (V+ + 0.3V) MAX7 AMJA ..............................................-55C to +125C LX (MAX738A/MAX744A) ................(V+ - 21V) to (V+ + 0.3V) Junction Temperatures: OUT.................................................................................25V MAX7 AC /AE ...................................................+150C SS, CC, SHDN .........................................-0.3V to (V+ + 0.3V) MAX7 AMJA.............................................................+175C Peak Switch Current (I ) ........................................................2A Storage Temperature Range ............................-65C to +160C LX Reference Current (I ) ...................................................2.5mA Lead Temperature (soldering, 10sec).............................+300C REF Continuous Power Dissipation (T = +70C) A 8-Pin Plastic DIP (derate 9.09mW/C above +70C)...727mW 8-Pin SO (derate 5.88mW/C above +70C) ...............471mW 16-Pin Wide SO (derate 9.52mW/C above +70C).....762mW 8-Pin CERDIP (derate 8.00mW/C above +70C) .......640mW 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 (Circuit of Figure 3, V+ = 9V for the MAX730A, V+ = 12V for the MAX738A/MAX744A, I = 0mA, T = T to T , LOAD A MIN MAX unless otherwise noted.) MAX730A MAX738A MAX744A PARAMETER CONDITIONS UNITS MIN TYP MAX MIN TYP MAX MIN TYP MAX 0mA < I < 450mA, LOAD MAX730AC V+ = 6.0V 0mA < I < 450mA, LOAD 4.75 5.00 5.25 to 11.0V MAX730AE 0mA < I < 300mA, LOAD MAX730AM 0mA < I < 450mA, LOAD MAX738AC/AE 0mA < I < 350mA, LOAD MAX738AM V+ = 6.0V 4.75 5.00 5.25 4.75 5.00 5.25 to 16.0V Output Voltage V 0mA < I < 500mA, LOAD MAX744AC/AE 0mA < I < 375mA, LOAD MAX744AM V+ = 10.2V to 16.0V, 4.75 5.00 5.25 0mA < I < 750mA LOAD 0mA < I < 750mA, LOAD MAX744AC/AE V+ = 9.0V 4.75 5.00 5.25 to 16.0V 0mA < I < 600mA, LOAD MAX744AM Input Voltage 5.2 11.0 6.0 16.0 6.0 16.0 V Range V+ = 5.2V to 11.0V 0.15 Line Regulation %/V V+ = 6.0V to 16.0V 0.15 0.15 2 MAX730A/MAX738A/MAX744A