MAX1540A/MAX1541 19-2861 Rev 3 2/07 Dual Step-Down Controllers with Saturation Protection, Dynamic Output, and Linear Regulator General Description Features Inductor-Saturation Protection The MAX1540A/MAX1541 dual pulse-width modulation (PWM) controllers provide the high efficiency, excellent Accurate Differential Current-Sense Inputs transient response, and high DC-output accuracy nec- Dual Ultra-High-Efficiency Quick-PWMs with essary for stepping down high-voltage batteries to gen- 100ns Load-Step Response erate low-voltage chipset and RAM power supplies in MAX1540A notebook computers. 1.8V/1.2V Fixed or 0.7V to 5.5V Adjustable The Maxim proprietary Quick-PWM controllers are Output (OUT1) free running, constant on-time with input feed forward. 2.5V/1.5V Fixed or 0.7V to 5.5V Adjustable This configuration provides ultra-fast transient Output (OUT2) response, wide input-output (I/O) differential range, low Fixed 5V, 100mA Linear Regulator supply current, and tight load-regulation characteris- MAX1541 tics. The controllers can accurately sense the inductor External Reference Input (REFIN1) current across an external current-sense resistor in Dynamically Selectable Output Voltage0.7V series with the output to ensure reliable overload and to 5.5V (OUT1) inductor saturation protection. Alternatively, the con- 2.5V/1.8V Fixed or 0.7V to 5.5V Adjustable trollers can use the synchronous rectifier itself or loss- Output (OUT2) less inductor current-sensing methods to provide Optional Power-Good and Fault Blanking overload protection with lower power dissipation. During Transitions Fixed 5V or Adjustable 100mA Linear Regulator For a single step-down PWM controller with inductor- 1% V Accuracy over Line and Load saturation protection, external-reference input voltage, OUT and dynamically selectable output voltages, refer to the 2V to 28V Battery Input Range MAX1992/MAX1993 data sheet. 170kHz to 620kHz Selectable Switching Frequency Applications Overvoltage/Undervoltage-Protection Option Notebook Computers 1.7ms Digital Soft-Start Core/I/O Supplies as Low as 0.7V Drives Large Synchronous-Rectifier FETs 0.7V to 5.5V Supply Rails 2V 0.7% Reference Output Separate Power-Good Window Comparators CPU/Chipset/GPU with Dynamic Voltage Core Supplies (MAX1541) Pin Configurations DDR Memory Termination (MAX1541) Active Termination Buses (MAX1541) TOP VIEW Ordering Information 25 16 BST2 DH1 PIN- PKG PGOOD1 26 15 LX2 PART TEMP RANGE PACKAGE CODE OUT1 27 14 DH2 13 PGOOD2 FB1 28 32 Thin QFN MAX1540AETJ -40C to +85C T3255-4 MAX1540A 5mm x 5mm 29 12 OUT2 CSN1 CSP1 30 11 FB2 32 Thin QFN MAX1540AETJ+ -40C to +85C T3255-4 10 CSN2 ON2 31 5mm x 5mm 9 CSP2 ON1 32 40 Thin QFN MAX1541ETL -40C to +85C T4066-5 6mm x 6mm 40 Thin QFN MAX1541ETL+ -40C to +85C T4066-5 6mm x 6mm +Denotes a lead-free package. THIN QFN A SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES. Pin Configurations continued at end of data sheet. Quick-PWM is a trademark of Maxim Integrated Products, Inc. Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE OVP/UVP 1 24 LX1 SKIP 2 23 BST1 LSAT 3 22 LDOON TON 4 21 DL1 V 5 20 LDOOUT CC ILIM1 6 19 V+ ILIM2 7 18 DL2 REF 8 17 GNDDual Step-Down Controllers with Saturation Protection, Dynamic Output, and Linear Regulator ABSOLUTE MAXIMUM RATINGS V+, LDOON to GND ...............................................-0.3V to +28V DH to LX ..................................................-0.3V to (BST + 0.3V) LDOOUT to GND (MAX1540A, Note 1)....................-0.3V to +6V LX to GND................................................................-2V to +30V LDOOUT to GND (MAX1541, Note 1) ....................-0.3V to +28V BST to LX ..............................................................-0.3V to +6V V to GND (MAX1541, Note 1) ..............................-0.3V to +6V REF Short Circuit to GND...........................................Continuous DD V , ON to GND.....................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) CC A SKIP, PGOOD to GND............................................-0.3V to +6V 32-Pin 5mm x 5mm Thin QFN (derated 21.3mW/C FB , CSP , ILIM to GND.........................................-0.3V to +6V above +70C).............................................................1702mW TON, OVP/UVP, LSAT to GND ...................-0.3V to (V + 0.3V) 40-Pin 6mm x 6mm Thin QFN (derated 26.3mW/C CC REF, OUT to GND.....................................-0.3V to (V + 0.3V) above +70C).............................................................2105mW CC LDOIN to GND (MAX1541).....................................-0.3V to +28V Operating Temperature Range ...........................-40C to +85C REFIN1, GATE, OD, FBLDO to GND (MAX1541).....-0.3V to +6V Junction Temperature......................................................+150C FBLANK, CC1 to GND (MAX1541).............-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C CC DL to GND (Note 1) ..................................-0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) .................................+300C DD CSN to GND ............................................................-2V to +30V Note 1: For the MAX1540A, the gate-driver input supply (V ) is internally connected to the fixed 5V linear-regulator output DD (LDOOUT), and the linear-regulator input supply (LDOIN) is internally connected to the battery voltage input (V+). 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, V = V = ON1 = ON2 = 5V, SKIP = GND, LDOIN (MAX1541) = V+, T = 0C to +85C, unless otherwise noted. Typical CC DD A values are at T = +25C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS INPUT SUPPLIES (Note 1) MAX1540A: battery voltage, V+ > V 5.5 28 LDOOUT V IN MAX1541: battery voltage, V+ > V 228 LDOOUT Input Voltage Range V V V (MAX1541) 4.5 5.5 V BIAS CC, DD MAX1541: LDO input supply, V 4.5 28 LDOIN V > V LDOIN LDOOUT FB1 and FB2 forced above the regulation 0.7 1.5 point, LSAT = GND Quiescent Supply Current (V)I mA CC CC FB1 and FB2 forced above the regulation 1.8 point, ON1 or ON2 = V , V > 0.5V CC LSAT Quiescent Supply Current FB1 and FB2 forced above the regulation I <1 5 A DD (V , MAX1541 Only) point, ON1 or ON2 = V DD CC MAX1540A: FB1 and FB2 forced above the regulation point, ON1 or ON2 = V , 150 CC V = V+ = 28V LDOON Quiescent Supply Current (V+) I A V+ MAX1541: ON1 or ON2 = V , CC 25 40 V = V+ = 28V LDOON FB1 and FB2 forced above the regulation Quiescent Supply Current point, ON1 or ON2 = V , I 110 A LDOIN CC (LDOIN, MAX1541 Only) V = V+ = 28V LDOON Standby Supply Current (V ) ON1 = ON2 = GND, V = V+ = 28V <1 5 A CC LDOON 2 MAX1540A/MAX1541