TC7662A

EVALUATION KIT AVAILABLE TC7662A CHARGE PUMP DC-TO-DC CONVERTER FEATURES s s s s s s s Wide Operating Range ............................. 3V to 18V Increased Output Current .............................. 40mA Pin Compatible with ICL7662/SI7661/TC7660/ LTC1044 No External Diodes Required Low Output Impedance @ IL = 20mA ....... 40Ω Typ. No Low-Voltage Terminal Required CMOS Construction GENERAL DESCRIPTION The TC7662A is a pin-compatible upgrade to the Industry standard TC7660 charge pump voltage converter. It converts a +3V to +18V input to a corresponding –3V to –18V output using only two low-cost capacitors, eliminating inductors and their associated cost, size and EMI. In addition to a wider power supply input range (3V to 18V versus 1.5V to 10V for the TC7660), the TC7662A can source output currents as high as 40mA. The on-board oscillator operates at a nominal frequency of 12kHz. Operation below 10kHz (for lower supply current applications) is also possible by connecting an external capacitor from OSC to ground. The TC7662A directly is recommended for designs requiring greater output current and/or lower input/output voltage drop. It is available in 8-pin PDIP, and CerDIP packages in commercial and extended temperature ranges. PIN CONFIGURATION PDIP/CerDIP NC 1 C+ 2 8 VDD 7 OSC ORDERING INFORMATION Part No. TC7662ACPA TC7662AEPA TC7662AIJA TC7662AMJA Package 8-Pin Plastic DIP 8-Pin Plastic DIP 8-Pin CerDIP 8-Pin CerDIP Temperature Range 0°C to +70°C – 40°C to +85°C – 25°C to +85°C – 55°C to +125°C GND 3 C– 4 TC7662A 6 NC 5 VOUT NC = NO INTERNAL CONNECTION FUNCTIONAL BLOCK DIAGRAM 8 I COSC 7 LEVEL SHIFT P SW1 2 CAP + TC7662A VDD + – Q F/F C Q COMPARATOR WITH HYSTERESIS VREF LEVEL SHIFT N SW4 + CP EXT GND 3 + LEVEL SHIFT OUT N SW2 4 – CR EXT CAP RL LEVEL SHIFT N SW3 5 VOUT © 2001 Microchip Technology Inc. DS21468 TC7662A-5 9/11/96 CHARGE PUMP DC-TO-DC CONVERTER TC7662A ABSOLUTE MAXIMUM RATINGS* Supply Voltage V DD to GND .................................... +18V Input Voltage (Any Pin) ........... (VDD + 0.3) to (V SS – 0.3) Current Into Any Pin ................................................. 10mA Operating Temperature Range C Suffix .................................................. 0°C to +70°C I Suffix .............................................. – 25°C to +85°C E Suffix ............................................. – 40°C to +85°C M Suffix .......................................... – 55°C to +125°C Power Dissipation (TA ≤ 70°C) Plastic DIP ......................................................730mW CerDIP ...........................................................800mW SOIC ........................................................................... Package Thermal Resistance CPA, EPA θJA .............................................. 140°C/W IJA, MJA θJA .................................................. 90°C/W Storage Temperature Range ................ – 65°C to +150°C Lead Temperature (Soldering, 10 sec) ................. +300°C ESD Protection ...................................................... ±2000V Output Short Circuit ................. Continuous (at 5.5V Input) * Static-sensitive device. Unused devices must be stored in conductive material. Protect devices from static discharge and static fields. Stresses above 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 above 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: VDD = 15V, TA = +25°C (See Test Circuit), unless otherwise specified. Symbol V DD IS Parameter Supply Voltage Supply Current Test Conditions RL = ∞ V DD = +15V 0°C ≤ TA ≤ +70°C – 55°C ≤ TA ≤ +125°C V DD = +5V 0°C ≤ TA ≤ +70°C – 55°C ≤ TA ≤ +125°C IL = 20mA, V DD = +15V IL = 40mA, V DD = +15V IL = 3mA, V DD = +5V V DD = +15V RL = 2 kΩ VDD = +15V RL = ∞ Over Operating Temperature Range Min 3 — — — — — — — — — — 93 99 96 Typ — 510 560 650 190 210 210 40 50 100 12 97 99.9 — Max 18 700 — — — — — 50 60 125 — — — — Unit V µA RO Output Source Resistance Oscillator Frequency Power Efficiency Voltage Efficiency Ω COSC PEFF VEFF kHz % % TC7662A-5 9/11/96 2 © 2001 Microchip Technology Inc. DS21468 CHARGE PUMP DC-TO-DC CONVERTER TC7662A TEST CIRCUIT EPR NC + 10 µF 1 2 8 7 TC7662A 6 5 NC C OSC IS IL RL V+ (+5V) ESL ESR C CP 3 4 VOUT (–5V) CR + 10 µF Figure 1. Capacitor Equivalent Circuit APPLICATIONS INFORMATION Theory of Operation The TC7662A is a capacitive charge pump (sometimes called a switched-capacitor circuit), where four MOSFET switches control the charge and discharge of a capacitor. The functional diagram (page 1) shows how the switching action works. SW1 and SW2 are turned on simultaneously, charging C1 to the supply voltage, VDD. This assumes that the ON resistance of the MOSFETs in series with the capacitor produce a charging time (3 time constants) less than the ON time provided by the oscillator frequency, as shown: 3 (RDS(ON) C1)