TC682 TELCOM | Alldatasheet

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Technical content

4-21TELCOM SEMICONDUCTOR, INC. INVERTING VOLTAGE DOUBLER

FEATURES

n 99.9% Voltage Conversion Efficiency n 92% Power Conversion Efficiency n Only 3 External Capacitors Required n 185µA Supply Current n Space-Saving 8-Pin SOIC and 8-Pin Plastic DIP Packages

APPLICATIONS

n – 10V from +5V Logic Supply n – 6V from a Single 3V Lithium Cell n Portable Handheld Instruments n Cellular Phones n LCD Display Bias Generator n Panel Meters n Operational Amplifier Power Supplies GENERAL DESCRIPTION The TC682 is a CMOS charge pump converter that provides an inverted doubled output from a single positive supply. An on-board 12kHz (typical) oscillator provides the clock and only 3 external capacitors are required for full circuit implementation. Low output source impedance (typically 140Ω ), pro- vides output current up to 10mA. The TC682 features low quiescent current and high efficiency, making it the ideal choice for a wide variety of applications that require a negative voltage derived from a single positive supply (for example: generation of – 6V from a 3V lithium cell or – 10V generated from a +5V logic supply). The minimum external parts count and small physical size of the TC682 make it useful in many medium-current, dual voltage analog power supplies. TC682 PIN CONFIGURATIONS

ORDERING INFORMATION

Part No. Package Temp. Range TC682COA 8-Pin SOIC 0 °C to +70°C TC682CPA 8-Pin Plastic DIP 0 °C to +70°C TC682EOA 8-Pin SOIC – 40 °C to +85°C TC682EPA 8-Pin Plastic DIP – 40 °C to +85°C TC7660EV Evaluation Kit for Charge Pump Family GND GND C 2+ C 2– C 1+ C 1 C 2 C 1– VIN VIN VOUT VOUT INV = – (2 x V )OUT All Caps = 3.3µF COUT TC682 +2.4V < VIN < +5.5V TC682-2 8/21/96 TYPICAL OPERATING CIRCUIT TC682CPA TC682EPA GNDVOUT C 2– C 1– C 2+ C 1+ NC NC VIN TC682COA TC682EOA GNDVOUT C 2– C 1– C 2+ C 1+ VIN 8-Pin DIP 8-Pin SOIC EVALUATION KIT AVAILABLE

4-22 TELCOM SEMICONDUCTOR, INC. 6V IN Input. Power supply voltage.

8 N/C No Connection

Figure 1. TC682 Test Circuit Conditions for extended periods may affect device reliability. of any circuits described herein and makes no representations that they are free from patent infringement.

4-24 TELCOM SEMICONDUCTOR, INC. values of C1 and C2 will affect efficiency by changing ROUT . must be rated at 12VDC or greater. Table 1. ROUT vs. C1, C2 Table 2. VRIPPLE Peak- to-Peak vs. C3 (IOUT = 10mA) converter, with IL–= 10mA, the charge pump will droop 1.5V.

4-26 TELCOM SEMICONDUCTOR, INC. TYPICAL CHARACTERISTICS (FOSC = 12kHz) VIN (V) LOAD CURRENT (mA) 240 220 200 180 140 160 120 12 3 4 5 0 51 01 56 OUTPUT RESISTANCE ( Ω ) Output Resistance vs. VIN –7.5 –8.0 –8.5 –9.0 –9.5 –10.0 –10.5 VOUT (V) VOUT vs. Load Current VIN (V) 300 250 200 150 100 12 3 4 56 SUPPLY CURRENT ( µA) Supply Current vs. VIN VIN = 5VC1– C3 = 3.3µF TEMPERATURE ( °C) –50 0 50 100 200 180 160 140 120 100 OUTPUT SOURCE RESISTANCE ( Ω ) Output Source Resistance vs. Temperature VIN = 5V IOUT = 10mA NO LOAD VIN = 5V OUTPUT CURRENT (mA) 200 150 100 0 5 1510 20 OUTPUT RIPPLE (mV PK-PK) Output Ripple vs. Output Current C3 =100µF C3 =10µF TC682 INVERTING VOLTAGE DOUBLER