TC962CPA

EVALUATION KIT AVAILABLE 1 TC962 HIGH CURRENT CHARGE PUMP DC-TO-DC CONVERTER FEATURES s s s s s s s s Pin Compatible With TC7662/ICL7662/SI7661 High Output Current ....................................... 80mA No External Diodes Required Wide Operating Range ............................. 3V to 18V Low Output Impedance ............................. 28Ω Typ. No Low Voltage Terminal Required Application Zener On Chip OSC Frequency Doubling Pin Option for Smaller Output Capacitors GENERAL DESCRIPTION The TC962 is an advanced version of the industrystandard 7662 high-voltage DC-to-DC converter. Using improved design techniques and CMOS construction, the TC962 can source as much as 8mA versus the 7662’s 20mA capability. As an inverter, the TC962 can put out voltages as high as 18V and as low as 3V without the need for external diodes. The output impedance of the device is a low 28Ω (with the proper capacitors), voltage conversion efficiency is 99.9%, and power conversion efficiency is 97%. The low voltage terminal (pin 6) required in some 7662 applications has been eliminated. Grounding this terminal will double the oscillator frequency from 12kHz to 24kHz. This will allow the use of smaller capacitors for the same output current and ripple, in most applications. Only two external capacitors are required for inverter applications. In the event an external clock is needed to drive the TC962 (such as paralleling), driving this pin directly will cause the internal oscillator to sync to the external clock. 2 3 4 5 6 7 PIN CONFIGURATIONS (DIP and SOIC) 8-Pin DIP 8-Pin CerDIP ZENER CATHODE + C GND – C 1 2 3 4 • TC962CPA TC962EPA TC962IJA TC962MJA 8 7 6 5 VDD COSC FREQ x 2 V OUT 16-Pin SOIC Wide ZENER CATHODE NC C+ NC GND NC 1 2 3 4 5 6 7 8 16 15 14 13 VDD NC COSC NC FREQ x 2 NC V OUT NC TC962COE 12 11 10 9 ORDERING INFORMATION Part No. TC962COE TC962CPA TC962EPA TC962IJA TC962MJA TC7660EV C– NC Package Temp. Range 16-Pin SOIC Wide 0°C to +70°C 8-Pin Plastic DIP 0°C to +70°C 8-Pin Plastic DIP – 40°C to +85°C 8-Pin CerDIP – 25°C to +85°C 8-Pin CerDIP – 55°C to +125°C Evaluation Kit for Charge Pump Family VDD TC962 FUNCTIONAL BLOCK DIAGRAM 8 FREQ X 2 – OSC/C TIMING 6 7 LEVEL SHIFT P SW1 2 CAP + I I Q + – F/F C Q COMPARATOR WITH HYSTERESIS LEVEL SHIFT N SW4 + CP EXTERNAL 3 GND ZENER CATHODE 1 6.4V VREF + LEVEL SHIFT OUT N SW2 4 – CR EXT CAP RL LEVEL SHIFT N SW3 5 VOUT 8 TC962-8 9/16/96 TELCOM SEMICONDUCTOR, INC. 4-37 HIGH CURRENT CHARGE PUMP DC -TO-DC CONVERTER TC962 Pin 1, which is used as a test pin on the 7662, is a voltage reference zener on the TC962. This zener (6.4V at 5 mA) has a dynamic impedance of 12Ω and is intended for use where the TC962 is supplying current to external regulator circuitry and a reference is needed for the regulator circuit. (See applications section.) The TC962 is compatible with the LTC1044, SI7661, and ICL7662. It should be used in designs that require greater power and/or less input to output voltage drop. It offers superior performance over the ICL7660S. Package Power Dissipation (TA ≤ 70°C) SOIC ............................................................... 760mW PDIP ............................................................... 730mW CerDIP ............................................................800mW Package Thermal Resistance CerDIP, RθJ-A ................................................ 90°C/W PDIP, RθJ-A ................................................. 140°C/W *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. ABSOLUTE MAXIMUM RATINGS* Supply Voltage (VDD to GND) .................................. +18V Input Voltage Any Pin ............... (V DD + 0.3) to (V SS – 0.3) Current Into Any Pin ................................................. 10mA ESD Protection ..................................................... ±2000V Output Short Circuit ................. Continuous (at 5.5V Input) Storage Temperature Range ................ – 65°C to +150°C Lead Temperature (Soldering, 10 sec) ................. +300°C Operating Temperature Range CPA, COE ............................................. 0°C to +70°C IJA .................................................... – 25°C to +85°C EPA .................................................. – 40°C to +85°C MJA ................................................ – 55°C to +125°C ELECTRICAL CHARACTERISTICS: VDD = 15V, TA = +25°C (See Test Circuit), unless otherwise indicated. Symbol V DD IS Parameter Supply Voltage Supply Current V DD = 15V Test Conditions RL = ∞ TA = +25°C 0 ≤ TA ≤ +70°C –55 ≤ TA ≤ +125°C TA = +25°C 0 ≤ TA < +70°C –55 ≤ TA ≤ +125°C IL = 20mA, V DD = 15V IL = 80mA, V DD = 15V IL = 3mA, V DD = 5V Pin 6 Open Pin 6 GND V DD = 15V RL = 2 kΩ V DD = 15V RL = ∞ Over Temperature Range IZ = 5mA IL = 2.5mA to 7.5mA Min 3 — Typ — Max 18 — Unit V µA µA µA µA µA µA Ω Ω Ω kHz kHz % % % V Ω — V DD = 5V RO Output Source Resistance Oscillator Frequency Power Efficiency Voltage Efficiency — COSC PEFF VDEF — 93 99 96 6.0 — 510 560 650 190 210 210 32 35 — 12 24 97 99.9 — 6.2 12 700 37 40 50 — — — VZ ZZT Zener Voltage Zener Impedance 6.4 4-38 TELCOM SEMICONDUCTOR, INC. HIGH CURRENT CHARGE PUMP DC -TO-DC CONVERTER TC962 APPLICATIONS INFORMATION Theory of Operation The TC962 is a capacitive 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 CP to the supply voltage, VIN. This assumes that the on resistance of the MOSFETs in series with the capacitor results in a charging time (3 time constants) that is less than the on time provided by the oscillator frequency as shown: 3 (RDS(ON) CP)