MAX1680/MAX1681 19-1247 Rev 0 7/97 125mA, Frequency-Selectable, Switched-Capacitor Voltage Converters General Description Features The MAX1680/MAX1681 inductorless switched-capaci- Selectable Switching Frequencies: tor voltage converters either invert an input voltage of 125kHz/250kHz (MAX1680) +2.0V to +5.5V or double it while supplying up to 500kHz/1MHz (MAX1681) 125mA output current. They have a selectable-frequen- Allow Use of Small Capacitors cy option that allows the use of small capacitors: 4.7F (MAX1680), 1F (MAX1681). With their high output cur- (1F for the MAX1681) rent capability, these charge-pump devices are suit- 125mA Output Current able replacements for inductor-based regulators, which require more expensive external components and addi- 3.5 Output Impedance tional board space. 1A Logic-Controlled Shutdown The devices equivalent output resistance (typically Configurable as Voltage Inverters or Doublers 3.5) allows them to deliver as much as 125mA with only a 440mV drop. A shutdown feature reduces quies- +2.0V to +5.5V Input Voltage Range cent current to less than 1A. The MAX1680/MAX1681 Available in 8-Pin SO Packages are available in 8-pin SO packages. For devices that deliver up to 50mA in smaller MAX packages, refer to 90% Efficiency the MAX860/MAX861 data sheet. Applications Ordering Information Local Negative Supplies PART TEMP. RANGE PIN-PACKAGE MAX1680C/D 0C to +70C Dice* Interface Power Supplies MAX1680ESA -40C to +85C 8 SO Op-Amp Power Supplies MAX1681C/D 0C to +70C Dice* MAX1681ESA -40C to +85C 8 SO MOSFET Bias *Contact factory for dice specifications. Pin Configuration appears at end of data sheet. Typical Operating Circuits DOUBLED +V INPUT OUTPUT FSEL IN FSEL IN +3V TO +5.5V VOLTAGE C2 1F 1F CAP+ SHDN CAP+ SHDN C1 1F MAX1681 MAX1681 C1 GND LV LV 1F +V INPUT GND +4V TO +5.5V INVERTED CAP- OUT CAP- OUT OUTPUT 1F VOLTAGE C2 1F INVERTER CONFIGURATION DOUBLER CONFIGURATION NOTE: USE 4.7F CAPACITORS FOR MAX1680 NOTE: USE 4.7F CAPACITORS FOR MAX1680 INPUT VOLTAGE RANGE: +2.0V TO +5.5V. INPUT VOLTAGE RANGE: +2.5V TO +5.5V. Maxim Integrated Products 1 For free samples & the latest literature: 125mA, Frequency-Selectable, Switched-Capacitor Voltage Converters ABSOLUTE MAXIMUM RATINGS IN..............................................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A LV....................................................(V - 0.3V) to (V + 0.3V) SO (derate 5.88mW/C above +70C)..........................471mW OUT IN CAP+ ...........................................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C IN SHDN, FSEL ......................................(V - 0.3V) to (V + 0.3V) Junction Temperature......................................................+150C LV IN OUT, CAP- ..................................................................-6V to 0.3V Storage Temperature Range .............................-65C to +160C Continuous Output Current ..............................................135mA Lead Temperature (soldering, 10sec) .............................+300C Output Short-Circuit Duration to GND (Note 1) ...................1sec 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 (Typical Operating Circuits (inverter configuration), FSEL = LV = GND, V = 5V, C1 = C2 = 10F (MAX1680), C1 = C2 = 2.2F IN (MAX1681), T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS MAX1680 2.0 5.5 Inverter configuration, R = 1k, LV = GND L MAX1681 3.0 5.5 Input Voltage Range V V IN MAX1680 2.5 5.5 Doubler configuration, V R = 1k, LV = OUT L MAX1681 4.0 5.5 T = +25C 2.5 4.5 FSEL = IN A (125kHz) 5.4 MAX1680 T = +25C 5 9 FSEL = LV A (250kHz) 10.8 Supply Current I+ mA T = +25C 10 18 A FSEL = IN (500kHz) 21.6 MAX1681 T = +25C 20 36 FSEL = LV A (1MHz) 43.2 Output Voltage Under Load V I = 125mA -3.75 -4.56 V LOAD LOAD (Note 2) Output Resistance (Note 2) R FSEL = IN or LV 3.5 10 OUT Output Resistance to Ground R SHDN = IN 1 5 OUT(SHUT) in Shutdown Shutdown Current I+ OUT = GND, SHDN = IN 1 A SHDN Input Bias Current (SHDN) I -1 1 A SHDN Input Bias Current (FSEL) I -1 1 A FSEL V 1 IL Shutdown, FSEL Thresholds LV = GND (Note 3) V V 4 IH T = +25C 187 250 313 A FSEL = LV 157 348 MAX1680 T = +25C 94 125 156 A FSEL = IN 79 174 Switching Frequency f kHz OSC T = +25C 750 1000 1250 A FSEL = LV 570 1490 MAX1681 T = +25C 375 500 625 A FSEL = IN 285 745 2 MAX1680/MAX1681