MAX786 19-0160 Rev 2 4/97 Dual-Output Power-Supply Controller for Notebook Computers General Description Features The MAX786 is a system-engineered power-supply Dual PWM Buck Controllers (+3.3V and +5V) controller for notebook computers or similar battery- Two Precision Comparators or Level Translators powered equipment. It provides two high-performance step-down (buck) pulse-width modulators (PWMs) 95% Efficiency for +3.3V and +5V. Other features include dual, 420A Quiescent Current, 70A in Standby low-dropout, micropower linear regulators for CMOS/RTC back-up, and two precision low-battery- (linear regulators alive) detection comparators. 25A Shutdown Current (+5V linear alive) High efficiency (95% at 2A greater than 80% at loads 5.5V to 30V Input Range from 5mA to 3A) is achieved through synchronous recti- fication and PWM operation at heavy loads, and Small SSOP Package TM Idle Mode operation at light loads. The MAX786 uses Fixed Output Voltages: physically small components, thanks to high operating 3.3V (standard) frequencies (300kHz/200kHz) and a new current-mode PWM architecture that allows for output filter capacitors 3.45V (High-Speed Pentium) as small as 30F per ampere of load. Line- and load- 3.6V (PowerPC) transient responses are terrific, with a high 60kHz unity- Ordering Information gain crossover frequency allowing output transients to be corrected within four or five clock cycles. Low sys- PART TEMP. RANGE PIN-PACKAGE V OUT tem cost is achieved through a high level of integration MAX786CAI 0C to +70C 28 SSOP 3.3V and the use of low-cost, external N-channel MOSFETs. MAX786RCAI 0C to +70C 28 SSOP 3.45V Other features include low-noise, fixed-frequency PWM operation at moderate to heavy loads, and a synchro- Ordering Information continued at end of data sheet. nizable oscillator for noise-sensitive applications such Pin Configuration as electromagnetic pen-based systems and communi- cating computers. The MAX786 is a monolithic, BiCMOS IC available in fine-pitch, surface-mount TOP VIEW SSOP packages. CS3 FB3 Applications 1 28 SS3 DH3 Notebook Computers 2 27 Portable Data Terminals ON3 3 LX3 26 Communicating Computers D1 BST3 4 25 Pen-Entry Systems MAX786 D2 5 24 DL3 VH V+ 6 23 Q2 7 22 VL Typical Application Diagram Q1 FB5 8 21 GND PGND 9 20 +3.3V REF 10 19 DL5 P 5.5V POWER MEMORY TO SYNC 11 BST5 SECTION 18 30V +5V PERIPHERALS MAX786 SHDN 12 17 LX5 SHUTDOWN 13 ON5 16 DH5 POWER-GOOD 5V ON/OFF SS5 14 15 CS5 3.3V ON/OFF LOW-BATTERY WARNING SYNC SUSPEND POWER SSOP Idle Mode is a trademark of Maxim Integrated Products. Pentium is a trademark of Intel Corp. PowerPC is a trademark of IBM Corp. Maxim Integrated Products 1 For free samples & the latest literature: Dual-Output Power-Supply Controller for Notebook Computers ABSOLUTE MAXIMUM RATINGS V+ to GND................................................................-0.3V to 36V DH3 to LX3 ..............................................-0.3V to (BST3 + 0.3V) PGND to GND .......................................................................2V DH5 to LX5 ..............................................-0.3V to (BST5 + 0.3V) VL to GND ..................................................................-0.3V to 7V REF, VL Short to GND................................................Momentary BST3, BST5 to GND .................................................-0.3V to 36V REF Current........................................................................20mA LX3 to BST3 ...............................................................-7V to 0.3V VL Current ..........................................................................50mA LX5 to BST5 ...............................................................-7V to 0.3V Continuous Power Dissipation (T = +70C) A Inputs/Outputs to GND SSOP (derate 9.52mW/C above +70C)....................762mW (D1, D2, SHDN, ON5, REF, SS5, CS5, Operating Temperature Ranges FB5, SYNC, CS3,FB3, SS3, ON3)............-0.3V to (VL + 0.3V) MAX786CAI/MAX786 CAI .................................0C to +70C VH to GND ...............................................................-0.3V to 20V MAX786EAI/MAX786 EAI ...............................-40C to +85C Q1, Q2 to GND ............................................-0.3V to (VH + 0.3V) Lead Temperature (soldering, 10sec) ............................+300C DL3, DL5 to PGND.......................................-0.3V to (VL + 0.3V) 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+ = 15V, GND = PGND = 0V, I = I = 0mA, SHDN = ON3 = ON5 = 5V, other digital input levels are 0V or +5V, VL REF T = T to T , unless otherwise noted.) A MIN MAX PARAMETER CONDITIONS MIN TYP MAX UNITS 3.3V AND 5V STEP-DOWN CONTROLLERS Input Supply Range 5.5 30 V 0mV < (CS5-FB5) < 70mV, 6V < V + < 30V FB5 Output Voltage 4.80 5.08 5.20 V (includes load and line regulation) MAX786 3.17 3.35 3.46 0mV < (CS3-FB3) < 70mV, 6V < V + < 30V FB3 Output Voltage MAX786R 3.32 3.50 3.60 V (includes load and line regulation) MAX786S 3.46 3.65 3.75 Load Regulation Either controller (CS -FB = 0mV to 70mV) 2.5 % Line Regulation Either controller (V+ = 6V to 30V) 0.03 %/V Current-Limit Voltage CS3-FB3 or CS5-FB5 80 100 120 mV SS3/SS5 Source Current 2.5 4.0 6.5 A SS3/SS5 Fault Sink Current 2 mA INTERNAL REGULATOR AND REFERENCE VL Output Voltage ON5 = ON3 = 0V, 5.5V < V+ < 30V, 0mA < I < 25mA 4.5 5.5 V L VL Fault Lockout Voltage Falling edge, hysteresis = 1% 3.6 4.2 V VL/FB5 Switchover Voltage Rising edge of FB5, hysteresis = 1% 4.2 4.7 V REF Output Voltage No external load (Note 1) 3.24 3.36 V REF Fault Lockout Voltage Falling edge 2.4 3.2 V REF Load Regulation 0mA < I < 5mA (Note 2) 30 75 mV L V+ Shutdown Current SHDN = D1 = D2 = ON3 = ON5 = 0V, V+ = 30V 25 40 A V+ Standby Current D1 = D2 = ON3 = ON5 = 0V, V+ = 30V 70 120 A Quiescent Power Consumption D1 = D2 = 0V, FB5 = CS5 = 5.25V, 5.5 8.6 mW (both PWM controllers on) FB3 = CS3 = 3.5V V+ Off Current FB5 = CS5 = 5.25V, VL switched over to FB5 30 60 A COMPARATORS D1, D2 Trip Voltage Falling edge, hysteresis = 1% 1.61 1.69 V D1, D2 Input Current D1 = D2 = 0V, 5V 100 nA 2 MAX786