MAX1964/MAX1965 19-2084 Rev 0 7/01 Tracking/Sequencing Triple/Quintuple Power-Supply Controllers General Description Features The MAX1964/MAX1965 power-supply controllers are 4.5V to 28V Input Voltage Range designed to address cost-sensitive applications Master DC-DC Step-Down Converter: demanding voltage sequencing/tracking, such as Preset 3.3V or Adjustable (1.236V to 0.75 x V ) cable modem consumer premise equipment (CPE), IN xDSL CPE, and set-top boxes. Operating off a low-cost, Output Voltage unregulated DC supply (such as a wall adapter output), Fixed Frequency (200kHz) PWM Controller the MAX1964 generates three positive outputs and the No Current-Sense Resistor MAX1965 generates four positive outputs and one neg- Adjustable Current Limit ative output to provide an inexpensive system power 95% Efficient supply. Soft-Start The MAX1964 includes a current-mode synchronous Two (MAX1964)/Four (MAX1965) Analog Gain step-down controller and two positive regulator gain Blocks: blocks. The MAX1965 has one additional positive gain Positive Analog Blocks Drive Low-Cost PNP block and one negative regulator gain block. The main Pass Transistors to Build Positive Linear synchronous step-down controller generates a high- Regulators current output that is preset to 3.3V or adjustable from Negative Analog Block (MAX1965) Drives a 1.236V to 0.75 V with an external resistive-divider. IN Low-Cost NPN Pass Transistor to Build a The 200kHz operating frequency allows the use of low- cost aluminum-electrolytic capacitors and low-cost Negative Linear Regulator power magnetics. Additionally, the MAX1964/MAX1965 Power-Good Indicator step-down controllers sense the voltage across the low- Voltage Sequencing (MAX1964) or Tracking side MOSFETs on-resistance to efficiently provide the current-limit signal, eliminating the need for costly cur- (MAX1965) rent-sense resistors. Ordering Information The MAX1964/MAX1965 generate additional supply rails at low cost. The positive regulator gain blocks use TEMP. PIN- f OSC PART an external PNP pass transistor to generate low voltage RANGE PACKAGE (kHz) rails directly from the main step-down converter (such -40C to +85C as 2.5V or 1.8V from the main 3.3V output) or higher MAX1964TEEE 16 QSOP 200 voltages using coupled windings from the step-down MAX1965TEEP -40C to +85C 20 QSOP 200 converter (such as 5V, 12V, or 15V). The MAX1965s negative gain block uses an external NPN pass transis- tor in conjunction with a coupled winding to generate Pin Configurations -5V, -12V, or -15V. All output voltages are externally adjustable, providing TOP VIEW maximum flexibility. During startup, the MAX1964 fea- tures voltage sequencing and the MAX1965 features 1 20 POK 1 16 IN POK IN voltage tracking. Both controllers provide a power- 2 19 COMP 2 15 VL COMP VL good output that monitors all of the output voltages. OUT 3 14 BST OUT 3 18 BST Applications FB 4 MAX1964 13 DH FB 4 17 DH MAX1965 B2 5 12 LX B2 5 16 LX xDSL, Cable, and ISDN Modems FB2 6 11 DL FB2 6 15 DL Set-Top Boxes B3 7 10 GND B3 7 14 GND Wireless Local Loop FB3 8 9 ILIM FB3 8 13 ILIM B4 9 12 FB5 16-Pin QSOP FB4 10 11 B5 Typical Operating Circuit appears at end of data sheet. 20-Pin QSOP 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.Tracking/Sequencing Triple/Quintuple Power-Supply Controllers ABSOLUTE MAXIMUM RATINGS IN, B2, B3, B4 to GND............................................-0.3V to +30V Continuous Power Dissipation (T = +70C) A B5 to OUT...............................................................-20V to +0.3V 16-Pin QSOP (derate 8.3mW/C above +70C)...........666mW VL, POK, FB, FB2, FB3, FB4, FB5 to GND...............-0.3V to +6V 20-Pin QSOP (derate 9.1mW/C above +70C)...........727mW LX to BST..................................................................-6V to +0.3V Operating Temperature Range ...........................-40C to +85C BST to GND............................................................-0.3V to +36V Junction Temperature......................................................+150C DH to LX....................................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C BST DL, OUT, COMP, ILIM to GND......................-0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) .................................+300C L VL Output Current...............................................................50mA VL Short Circuit to GND.................................................. 100ms 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 = 12V, ILIM = FB = GND, V - V = 5V, T = 0C to +85C. Typical values are at T = +25C, unless otherwise noted.) IN BST LX A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS GENERAL Operating Input Voltage Range V 4.5 28 V IN (Note 1) V = 0, V = 4V, FB OUT MAX1964 1.25 2.5 Quiescent Supply Current I V = V = V = 1.5V, mA IN FB2 FB3 FB4 MAX1965 1.5 3.0 V = -0.1V FB5 VL REGULATOR Output Voltage VL 6V < V < 28V, 0.1mA < I <20mA 4.75 5.00 5.25 V IN LOAD Line Regulation V = 6V to 28V 3.0 % IN Undervoltage Lockout Trip Level V VL rising, 3% hysteresis (typ) 3.2 3.5 3.8 V UVLO Minimum Bypass Capacitance C 10m < ESR < 500m 1 F BYP(MIN) DC-DC CONTROLLER Output Voltage (Preset Mode) V FB = GND 3.272 3.34 3.355 V OUT Typical Output Voltage Range V V 0.75 V V OUT SET IN (Adjustable Mode) (Note 2) FB Set Voltage (Adjustable V FB = COMP 1.221 1.236 1.252 V SET Mode) FB Dual-Mode Threshold 50 100 150 mV FB Input Leakage Current I V = 1.5V 0.01 100 nA FB FB FB to COMP Transconductance g FB = COMP, I = 5 A 70 100 140 S m COMP Current-Sense Amplifier Voltage A V - V = 250mV 4.46 4.9 5.44 V/V LIM IN LX Gain Current-Limit Threshold V V = 5.0V 190 250 310 mV VALLEY ILIM (Internal Mode) Current-Limit Threshold V V = 2.5V 440 530 620 mV VALLEY ILIM (External Mode) Switching Frequency f 160 200 240 kHz OSC Dual Mode is a trademark of Maxim Integrated Products, Inc. 2 MAX1964/MAX1965