MAX868 19-1290 Rev 1 2/98 Regulated, Adjustable -2x Inverting Charge Pump General Description Features The MAX868 inverting charge pump provides a low-cost Regulated Negative Output Voltage and compact means of generating a regulated negative (up to -2 x V ) IN voltage up to -2 x V from a positive input voltage IN Ultra-Small, 10-Pin MAX Package between 1.8V and 5.5V. It uses a pulse-frequency- modulation (PFM) control scheme to generate the regulat- On-Demand Switching at up to 450kHz ed negative output voltage. PFM operation is obtained 30A Quiescent Supply Current by gating the internal 450kHz oscillator on and off as needed to maintain output voltage regulation. This Requires Only Four Small External Capacitors unique on-demand switching scheme gives the MAX868 1.8V to 5.5V Input Voltage Range excellent light-load efficiency without degrading its full- load operation (up to 30mA), permitting smaller capaci- 0.1A Logic-Controlled Shutdown tors to take advantage of the oscillators high switching frequency. Up to 30mA Output Current The MAX868 requires no inductors only four capacitors are required to build a complete DC-DC converter. Output voltage regulation is achieved by adding just two resistors. The MAX868 comes in a 10-pin MAX pack- age, which is only 1.11mm high and occupies just half Ordering Information the board area of a standard 8-pin SO. PART TEMP. RANGE PIN-PACKAGE Applications MAX868C/D 0C to +70C Dice* MAX868EUB -40C to +85C 10 MAX Small LCD Panels *Dice are tested at T = +25C. A Cell Phones Cordless Phones Camcorders Handy-Terminals, PDAs Medical Instruments Typical Operating Circuit Battery-Operated Equipment V = 1.8V TO 5.5V IN Configuration 1F SHDN IN TOP VIEW MAX868 C1+ FB GND 1 10 FB 0.1F OUT 2 9 SHDN C1- MAX868 V = 0V TO -2 x V C1- 3 8 C2+ OUT IN C2+ OUT PGND 4 7 IN 0.1F 2.2F C1+ 5 6 C2- C2- PGND GND MAX Maxim Integrated Products 1 For free samples & the latest literature: Regulated, Adjustable -2x Inverting Charge Pump ABSOLUTE MAXIMUM RATINGS IN to GND.................................................................-0.3V to +6V Output Current ....................................................................35mA OUT to GND ...........................................................+0.3V to -12V Short-Circuit Duration.................................................Continuous IN to OUT.................................................................-0.3V to -17V Continuous Power Dissipation (T = +70C) A C1+ to GND ........................................(V - 12V) to (V + 0.3V) 10-pin MAX (derate 5.6mW/C above +70C) ...........444mW IN IN C1- to GND.............................................................+0.3V to -12V Operating Temperature Range C2+ to GND....................................................(V + 0.3V) to -6V MAX868EUB ....................................................-40C to +85C IN C2- to GND...............................................................+0.3V to -6V Storage Temperature Range .............................-65C to +160C SHDN, FB to GND .......................................-0.3V to (V + 0.3V) Lead Temperature (soldering, 10sec) .............................+300C IN PGND to GND .......................................................-0.3V to +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 = +3.3V, SHDN = IN, C1 = C2 = 0.22F, C = 1F, C = 10F, T = 0C to +85C, unless otherwise noted. Typical values IN IN OUT A are at T = +25C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply-Voltage Range V R = 3k to GND 1.8 5.5 V IN L No load, V = -50mV 30 50 A FB Supply Current I IN FB = IN 5 mA Shutdown Current I , No load, SHDN = GND 0.1 1 A IN SHDN T = +25C 293 450 607 A Oscillator Frequency f V = 50mV kHz OSC FB T = 0C to +85C 270 630 A Closed-Loop Output R V = -5V 0.2 OUT,CL OUT Resistance T = +25C 70 100 A I = 5mA, FB = IN Open-Loop Output OUT R T = 0C to +85C 125 OUT A Resistance SHDN = GND (OUT pulls to GND) 15 50 T = +25C -30 30 mV A FB Trip Point V = 1.8V to 5.5V IN T = 0C to +85C -40 40 mV A V = 3.3V, V = -5V 12 IN OUT Output Current I Closed loop mA OUT V = 5V, V = -3.3V 30 IN OUT FB Input Bias Current V = 1.8V to 5.5V, T = +25C -50 1 50 nA IN A V 0.3V IL IN SHDN Input Threshold V = 1.8V to 5.5V V IN V 0.7V IH IN -100 1 100 nA SHDN Input Bias Current V = 5.5V, SHDN = IN or GND IN 2 MAX868