MAX1673 19-1334 Rev 0 1/98 Regulated, 125mA-Output, Charge-Pump DC-DC Inverter General Description Features The MAX1673 charge-pump inverter provides a low- Regulated Negative Output Voltage cost, compact means of generating a regulated nega- (up to -1 x V ) IN tive output from a positive input at up to 125mA. It 125mA Output Current requires only three small capacitors, and only two resis- tors to set its output voltage. The input range is 2V to 35A Quiescent Supply Current 5.5V. The regulated output can be set from 0V to -V in IN (Skip-mode regulation) Skip regulation mode or -1.5V to -V in Linear (LIN) IN 350kHz Fixed-Frequency, Low-Noise Output regulation mode. (Linear-mode regulation) In Skip mode, the MAX1673 regulates by varying its switching frequency as a function of load current. This 2V to 5.5V Input Range On-Demand switching gives the MAX1673 two 1A Logic-Controlled Shutdown advantages: very small capacitors and very low quies- cent supply current. At heavy loads, it transfers energy from the input to the output by switching at up to 350kHz. It switches more slowly at light loads, using only 35A quiescent supply current. In Linear mode, the MAX1673 switches at a constant 350kHz at all loads and regulates by controlling the current-path resistance. This provides constant- frequency ripple, which is easily filtered for low-noise Ordering Information applications. PART TEMP. RANGE PIN-PACKAGE This device also features a 1A logic-controlled shut- MAX1673ESA -40C to +85C 8 SO down mode and is available in a standard 8-pin SO package. For a device that delivers about 10mA and fits in a smaller package, refer to the MAX868. Applications Hard Disk Drives Measurement Instruments Camcorders Modems Analog Signal-Processing Digital Cameras Applications Typical Operating Circuit INPUT 2V TO 5.5V Pin Configuration ON IN REGULATED TOP VIEW OFF SHDN FB NEGATIVE OUTPUT (UP TO -1 x V , IN LIN/SKIP 1 8 IN MAX1673 UP TO 125mA) CAP+ OUT CAP+ 2 7 GND MAX1673 CAP- CAP- 3 6 FB LIN/SKIP GND SHDN 4 5 OUT SO On-Demand is a trademark of Maxim Integrated Products. Maxim Integrated Products 1 For free samples & the latest literature: Regulated, 125mA-Output, Charge-Pump DC-DC Inverter ABSOLUTE MAXIMUM RATINGS IN..............................................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A CAP+, FB, LIN/SKIP.....................................-0.3V to (V + 0.3V) (derate 5.88mW/C above +70C)...............................450mW IN SHDN........................................................................-0.3V to +6V Operating Temperature Range ...........................-40C to +85C OUT, CAP-................................................................-6V to +0.3V Junction Temperature......................................................+150C Continuous Output Current...............................................135mA Storage Temperature Range .............................-65C to +160C Output Short-Circuit Duration to GND (Note 1) ....................1sec Lead Temperature (soldering, 10sec) .............................+300C Note 1: Shorting OUT to IN may damage the device and should be avoided. 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 = V = +5V, C = 10F, C = 22F, C = 2.2F, T = -40C to +85C, unless otherwise noted. Typical values are at IN SHDN IN OUT FLY A T = +25C.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS LIN/SKIP = GND (Skip mode) 2.0 5.5 Input Voltage Range V V IN LIN/SKIP = IN (LIN mode) 2.7 5.5 LIN/SKIP = GND 0 Minimum Output Voltage V V OUT LIN/SKIP = IN -1.5 Maximum Output Current I 125 mA OUT(MAX) LIN/SKIP = IN -2.90 -3.02 -3.15 R1 =100k, 1%, (LIN mode) R2 = 60.4k, 1%, Output Voltage V V OUT I = 0mA to OUT 125mA, Figure 1 LIN/SKIP = GND -2.92 -3.02 -3.12 (Skip mode) V = -100mV, V = -3V, FB OUT 8 16 LIN/SKIP = IN (LIN mode) Quiescent Current (I Current) mA IN I Q V = -25mV, V = -3V, FB OUT 0.035 0.2 LIN/SKIP = GND (Skip mode) Shutdown Current (I Current) I SHDN = GND 0.1 1 A IN SHDN LIN/SKIP = IN 0.01 V = 4.5V to 5.5V, IN (LIN mode) Line Regulation V Figure 4, %/V LNR LIN/SKIP = GND V V REF IN 1 (Skip mode) LIN/SKIP = IN 0.01 I = 25mA to OUT (LIN mode) Load Regulation V 125mA, Figure 1 %/mA LDR LIN/SKIP = GND 0.005 (Skip mode) Open-Loop Output Resistance R LIN/SKIP = GND (Skip mode) 3.5 10 O (Dropout) Output Resistance to Ground SHDN = GND 1 5 in Shutdown Mode 2 MAX1673