EVALUATION KIT AVAILABLE TC7660 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER GENERAL DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Converts +5V Logic Supply to ±5V System Wide Input Voltage Range .................... 1.5V to 10V Efficient Voltage Conversion ......................... 99.9% Excellent Power Efficiency ............................... 98% Low Power Supply ............................... 80µA @ 5VIN Low Cost and Easy to Use — Only Two External Capacitors Required RS232 Negative Power Supply Available in Small Outline (SO) Package Improved ESD Protection ....................... Up to 3kV No Dx Diode Required for High Voltage Operation The TC7660 is a pin-compatible replacement for the Industry standard TC7660 charge pump voltage converter. It converts a +1.5V to +10V input to a corresponding – 1.5V to -10V output using only two low-cost capacitors, eliminating inductors and their associated cost, size and EMI. The on-board oscillator operates at a nominal frequency of 10kHz. Operation below 10kHz (for lower supply current applications) is possible by connecting an external capacitor from OSC to ground (with pin 1 open). The TC7660 is available in both 8-pin DIP and 8-pin SOIC packages in commercial and extended temperature ranges. ORDERING INFORMATION PIN CONFIGURATION (DIP and SOIC) NC 1 CAP + 2 GND 8 V+ NC 1 8 V+ 7 OSC CAP + 2 7 OSC GND 3 3 TC7660CPA 6 LOW VOLTAGE (LV) TC7660EPA CAP – 4 TC7660IJA 5 VOUT CAP – TC7660COA 6 LOW VOLTAGE (LV) TC7660CPA 5 VOUT 4 NC = NO INTERNAL CONNECTION Temperature Range Part No. Package TC7660COA 8-Pin SOIC 0°C to +70°C TC7660CPA 8-Pin Plastic DIP TC7660EOA 8-Pin SOIC – 40°C to +85°C 0°C to +70°C TC7660EPA 8-Pin Plastic DIP – 40°C to +85°C TC7660IJA 8-Pin CerDIP – 40°C to +85°C TC7660MJA 8-Pin CerDIP – 55°C to +125°C TC7660EV Evaluation Kit for Charge Pump Family FUNCTIONAL BLOCK DIAGRAM V + CAP + 8 OSC LV 7 RC OSCILLATOR ÷2 2 VOLTAGE– LEVEL TRANSLATOR 4 CAP – 6 5 VOUT INTERNAL VOLTAGE REGULATOR LOGIC NETWORK TC7660 3 GND © 2001 Microchip Technology Inc. DS21465A TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 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 Storage Temperature Range ................ – 65°C to +150°C Lead Temperature (Soldering, 10 sec) ................. +300°C ABSOLUTE MAXIMUM RATINGS* Supply Voltage ...................................................... +10.5V LV and OSC Inputs Voltage (Note 1) .......................... – 0.3V to (V++0.3V) for V+ < 5.5V + (V – 5.5V) to (V++0.3V) for V+ > 5.5V Current Into LV (Note 1) ..................... 20 µA for V+ > 3.5V Output Short Duration (VSUPPLY ≤ 5.5V) ........ Continuous Power Dissipation (TA ≤ 70°C) (Note 2) CerDIP ............................................................800mW Plastic DIP ...................................................... 730mW SOIC ............................................................... 470mW *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 operation sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS: Specifications Measured Over Operating Temperature Range With, V+ = 5V, COSC = 0, Test Circuit (Figure 1), unless otherwise indicated. Symbol Parameter I+ V+H Supply Current Supply Voltage Range, High V+L Supply Voltage Range, Low ROUT Output Source Resistance FOSC PEFF VOUT EFF ZOSC Oscillator Frequency Power Efficiency Voltage Conversion Efficiency Oscillator Impedance Test Conditions RL = ∞ Min ≤ TA ≤ Max, RL = 10 kΩ, LV Open Min ≤ TA ≤ Max, RL = 10 kΩ, LV to GND IOUT = 20mA, TA = 25°C IOUT = 20mA, 0°C ≤ TA ≤ +70°C (C Device) IOUT = 20mA, – 40°C ≤ TA ≤ +85°C (I Device) IOUT = 20mA, –55°C ≤ TA ≤ +125°C (M Device) V+ = 2V, IOUT = 3 mA, LV to GND 0°C ≤ TA ≤ +70°C V+ = 2V, IOUT = 3 mA, LV to GND – 55°C ≤ TA ≤ +125°C (Note 3) Pin 7 open RL = 5kΩ RL = ∞ V+ = 2V V+ = 5V Min Typ Max Unit — 3 80 — 180 10 µA V 1.5 — 3.5 V — — 70 — 100 120 Ω Ω — — 130 Ω — 104 150 Ω — 150 300 Ω — 160 600 Ω — 95 97 — — 10 98 99.9 1 100 — — — — — kHz % % MΩ kΩ NOTES: 1. Connecting any input terminal to voltages greater than V+ or less than GND may cause destructive latch-up. It is recommended that no inputs from sources operating from external supplies be applied prior to "power up" of the TC7660. 2. Derate linearly above 50°C by 5.5 mW/°C. 3. TC7660M only. 4. The TC7660 can be operated without the Dx diode over full temperature and voltage range. TC7660-7 9/30/96 2 © 2001 Microchip Technology Inc. DS21465A CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 1) Power Conversion Eff. vs. Osc. Freq. 100 POWER CONVERSION EFFICIENCY (%) Operating Voltage vs. Temperature 12 SUPPLY VOLTAGE (V) 10 8 6 SUPPLY VOLTAGE RANGE 4 2 0 –55 –25 0 +25 +50 +75 +100 +125 TEMPERATURE (°C) Output Source Resistance vs. Supply Voltage 1k 100Ω 10Ω 1 2 3 4 5 6 SUPPLY VOLTAGE (V) 7 92 90 88 86 84 82 OSCILLATOR FREQUENCY (kHz) 1k 100 DS21465A 1k OSCILLATOR FREQUENCY (Hz) 10k IOUT = 1 mA 450 400 200 150 V + = +2V 100 V + = +5V 50 –25 0 +25 +50 +75 +100 +125 TEMPERATURE (°C) V+ = +5V 18 16 14 12 10 8 6 –55 10 © 2001 Microchip Technology Inc. TA = +25°C V+ = +5V 80 100 20 TA = +25°C V+ = +5V 10 100 1000 OSCILLATOR CAPACITANCE (pF) IOUT = 15 mA Unloaded Osc. Freq. vs. Temperature 10k OSCILLATOR FREQUENCY (Hz) 94 0 –55 8 Freq. of Osc. vs. Ext. Osc. Capacitance 1 IOUT = 1 mA 500 TA = +25°C 0 96 Output Source Resistance vs. Temperature OUTPUT SOURCE RESISTANCE (Ω) OUTPUT SOURCE RESISTANCE (Ω) 10k 98 10k 3 –25 0 +25 +50 +75 +100 +125 TEMPERATURE (°C) TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 TYPICAL CHARACTERISTICS (Cont.) Output Voltage vs. Load Current 5 –1 4 –2 3 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) Output Voltage vs. Output Current 0 –3 –4 –5 –6 –7 –8 TA = +25°C LV OPEN –9 TA = +25°C V+ = +5V 2 1 0 –1 –2 –3 SLOPE 55Ω –4 –10 –5 0 10 20 30 40 50 60 70 80 90 100 OUTPUT CURRENT (mA) 0 10 20 30 40 50 60 70 LOAD CURRENT (mA) 80 90 18 80 16 70 14 60 12 50 10 40 8 30 6 20 4 10 2 0 1.5 3.0 4.5 6.0 7.5 LOAD CURRENT (mA) 0 9.0 100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 TA = +25°C V+ = +5V 10 10 SUPPLY CURRENT (mA) (Note) 20 TA = +25°C V+ = 2V POWER CONVERSION EFFICIENCY (%) 100 SUPPLY CURRENT (mA) (Note) POWER CONVERSION EFFICIENCY (%) Supply Current and Power Conversion Efficiency vs. Load Current 0 0 10 20 30 40 50 LOAD CURRENT (mA) 60 Output Voltage vs. Load Current 2 OUTPUT VOLTAGE (V) TA = +25°C V+ = +2V 1 0 –1 SLOPE 150Ω –2 0 TC7660-7 9/30/96 1 2 3 4 5 6 LOAD CURRENT (mA) 7 8 4 © 2001 Microchip Technology Inc. DS21465A CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 The four switches in Figure 2 are MOS power switches; S1 is a P-channel device, and S2, S3 and S4 are N-channel devices. The main difficulty with this approach is that in integrating the switches, the substrates of S3 and S4 must always remain reverse-biased with respect to their sources, but not so much as to degrade their ON resistances. In addition, at circuit start-up, and under output short circuit conditions (VOUT = V+), the output voltage must be sensed and the substrate bias adjusted accordingly. Failure to accomplish this will result in high power losses and probable device latch-up. This problem is eliminated in the TC7660 by a logic network which senses the output voltage (VOUT) together with the level translators, and switches the substrates of S3 and S4 to the correct level to maintain necessary reverse bias. The voltage regulator portion of the TC7660 is an integral part of the anti-latch-up circuitry. Its inherent voltage drop can, however, degrade operation at low voltages. To improve low-voltage operation, the LV pin should be connected to GND, disabling the regulator. For supply voltages greater than 3.5V, the LV terminal must be left open to ensure latch-up-proof operation and prevent device damage. IS C1 10µF + 1 8 2 7 3 TC7660 4 COSC* 6 5 IL V+ (+5V) RL VO + C2 10µF NOTES: * For large values of COSC (>1000pF), the values of C1 and C2 should be increased to 100µF. Figure 1. TC7660 Test Circuit Detailed Description The TC7660 contains all the necessary circuitry to implement a voltage inverter, with the exception of two external capacitors, which may be inexpensive 10 µF polarized electrolytic capacitors. Operation is best understood by considering Figure 2, which shows an idealized voltage inverter. Capacitor C1 is charged to a voltage, V+, for the half cycle when switches S1 and S3 are closed. (Note: Switches S2 and S4 are open during this half cycle.) During the second half cycle of operation, switches S2 and S4 are closed, with S1 and S3 open, thereby shifting capacitor C1 negatively by V+ volts. Charge is then transferred from C1 to C2, such that the voltage on C2 is exactly V+, assuming ideal switches and no load on C2. V+ GND S1 S2 S3 S4 Theoretical Power Efficiency Considerations In theory, a capacitive charge pump can approach 100% efficiency if certain conditions are met: (1) The drive circuitry consumes minimal power. (2) The output switches have extremely low ON resistance and virtually no offset. (3) The impedances of the pump and reservoir capacitors are negligible at the pump frequency. C2 VOUT = – VIN Figure 2. Idealized Charge Pump Inverter © 2001 Microchip Technology Inc. DS21465A 5 TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 The output characteristics of the circuit in Figure 3 are those of a nearly ideal voltage source in series with 70Ω. Thus, for a load current of –10mA and a supply voltage of +5V, the output voltage would be – 4.3V. The dynamic output impedance of the TC7660 is due, primarily, to capacitive reactance of the charge transfer capacitor (C1). Since this capacitor is connected to the output for only 1/2 of the cycle, the equation is: The TC7660 approaches these conditions for negative voltage multiplication if large values of C1 and C2 are used. Energy is lost only in the transfer of charge between capacitors if a change in voltage occurs. The energy lost is defined by: E = 1/2 C1 (V12 – V22) V1 and V2 are the voltages on C1 during the pump and transfer cycles. If the impedances of C1 and C2 are relatively high at the pump frequency (refer to Figure 2), compared to the value of RL, there will be a substantial difference in voltages V1 and V2. Therefore, it is not only desirable to make C2 as large as possible to eliminate output voltage ripple, but also to employ a correspondingly large value for C1 in order to achieve maximum efficiency of operation. 2 XC = = 3.18Ω, 2πf C1 where f = 10kHz and C1 = 10µF. V+ Dos and Don'ts • Do not exceed maximum supply voltages. C1 10µF • Do not connect LV terminal to GND for supply voltages greater than 3.5V. + V+ • Do not short circuit the output to supply for voltages above 5.5V for extended periods; however, transient conditions including start-up are okay. 1 8 2 7 3 TC7660 • When using polarized capacitors in the inverting mode, the + terminal of C1 must be connected to pin 2 of the TC7660 and the + terminal of C2 must be connected to GND Pin 3. + 5 4 * NOTES: 6 VOUT* C2 10µF 1. VOUT = –n V+ for 1.5V V+ 10V Figure 3. Simple Negative Converter Simple Negative Voltage Converter Paralleling Devices Figure 3 shows typical connections to provide a negative supply where a positive supply is available. A similar scheme may be employed for supply voltages anywhere in the operating range of +1.5V to +10V, keeping in mind that pin 6 (LV) is tied to the supply negative (GND) only for supply voltages below 3.5V. Any number of TC7660 voltage converters may be paralleled to reduce output resistance (Figure 4). The reservoir capacitor, C2, serves all devices, while each device requires its own pump capacitor, C1. The resultant output resistance would be approximately: ROUT = TC7660-7 9/30/96 6 ROUT (of TC7660) n (number of devices) © 2001 Microchip Technology Inc. DS21465A CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 V 1 8 2 C1 + TC7660 3 4 7 1 8 6 2 7 5 "1" C1 TC7660 3 "n" 4 RL 6 5 + C2 Figure 4. Paralleling Devices Lowers Output Impedance Cascading Devices device latch-up, a 1kΩ resistor must be used in series with the clock output. In a situation where the designer has generated the external clock frequency using TTL logic, the addition of a 10kΩ pull-up resistor to V+ supply is required. Note that the pump frequency with external clocking, as with internal clocking, will be 1/2 of the clock frequency. Output transitions occur on the positive-going edge of the clock. It is also possible to increase the conversion efficiency of the TC7660 at low load levels by lowering the oscillator frequency. This reduces the switching losses, and is achieved by connecting an additional capacitor, COSC, as shown in Figure 7. Lowering the oscillator frequency will cause an undesirable increase in the impedance of the pump (C1) and the reservoir (C2) capacitors. To overcome this, increase the values of C1 and C2 by the same factor that the frequency has been reduced. For example, the addition of a 100pF capacitor between pin 7 (OSC) and pin 8 (V+) will lower the oscillator frequency to 1kHz from its nominal frequency of 10kHz (a multiple of 10), and necessitate a corresponding increase in the values of C1 and C2 (from 10µF to 100µF). The TC7660 may be cascaded as shown (Figure 6) to produce larger negative multiplication of the initial supply voltage. However, due to the finite efficiency of each device, the practical limit is 10 devices for light loads. The output voltage is defined by: VOUT = –n (VIN) where n is an integer representing the number of devices cascaded. The resulting output resistance would be approximately the weighted sum of the individual TC7660 ROUT values. Changing the TC7660 Oscillator Frequency It may be desirable in some applications (due to noise or other considerations) to increase the oscillator frequency. This is achieved by overdriving the oscillator from an external clock, as shown in Figure 6. In order to prevent possible V+ 1 8 2 7 + 10µF 3 TC7660 4 "1" 1 6 5 8 2 + 10µF 7 3 TC7660 6 4 "n" 5 VOUT* + * NOTES: 1. VOUT = –n V + for 1.5V V+ 10µF 10V Figure 5. Increased Output Voltage by Cascading Devices © 2001 Microchip Technology Inc. DS21465A 7 TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 1 8 2 7 Combined Negative Voltage Conversion and Positive Supply Multiplication V+ V+ 1 kΩ + 3 10µF TC7660 6 5 4 Figure 9 combines the functions shown in Figures 3 and 8 to provide negative voltage conversion and positive voltage multiplication simultaneously. This approach would be, for example, suitable for generating +9V and – 5V from an existing +5V supply. In this instance, capacitors C1 and C3 perform the pump and reservoir functions, respectively, for the generation of the negative voltage, while capacitors C2 and C4 are pump and reservoir, respectively, for the multiplied positive voltage. There is a penalty in this configuration which combines both functions, however, in that the source impedances of the generated supplies will be somewhat higher due to the finite impedance of the common charge pump driver at pin 2 of the device. CMOS GATE VOUT + 10µF Figure 6. External Clocking V C1 + 1 8 2 7 3 TC7660 4 + COSC 6 5 V+ VOUT C2 + 1 8 2 7 Figure 7. Lowering Oscillator Frequency 3 Positive Voltage Multiplication + C1 The TC7660 may be employed to achieve positive voltage multiplication using the circuit shown in Figure 8. In this application, the pump inverter switches of the TC7660 are used to charge C1 to a voltage level of V+– VF (where V+ is the supply voltage and VF is the forward voltage drop of diode D1). On the transfer cycle, the voltage on C1 plus the supply voltage (V+) is applied through diode D2 to capacitor C2. The voltage thus created on C2 becomes (2 V+) – (2 VF), or twice the supply voltage minus the combined forward voltage drops of diodes D1 and D2. The source impedance of the output (VOUT) will depend on the output current, but for V+ = 5V and an output current of 10 mA, it will be approximately 60Ω. 8 2 7 3 4 TC7660 D1 6 5 C1 5 D2 + C3 VOUT = (2 V +) – (2 VF) + C4 Efficient Positive Voltage Multiplication/Conversion Since the switches that allow the charge pumping operation are bidirectional, the charge transfer can be performed backwards as easily as forwards. Figure 10 shows a TC7660 transforming – 5V to +5V (or +5V to +10V, etc.). The only problem here is that the internal clock and switchdrive section will not operate until some positive voltage has been generated. An initial inefficient pump, as shown in Figure 9, could be used to start this circuit up, after which it will bypass the other (D1 and D2 in Figure 9 would never turn on), or else the diode and resistor shown dotted in Figure 10 can be used to "force" the internal regulator on. + + 6 + Figure 9. Combined Negative Converter and Positive Multiplier VOUT = (2 V+) – (2 VF) D2 4 D1 C2 V+ 1 TC7660 VOUT = – (V+– VF) C2 Figure 8. Positive Voltage Multiplier TC7660-7 9/30/96 8 © 2001 Microchip Technology Inc. DS21465A CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 VOUT = –V– C1 10µF + 1 8 2 7 + 10µF 1 MΩ TC7660 3 4 6 5 V– INPUT Figure 10. Positive Voltage Conversion Voltage Splitting The same bidirectional characteristics used in Figure 10 can also be used to split a higher supply in half, as shown in Figure 11. The combined load will be evenly shared between the two sides. Once again, a high value resistor to the LV pin ensures start-up. Because the switches share the load in parallel, the output impedance is much lower than in the standard circuits, and higher currents can be drawn from the device. By using this circuit, and then the circuit of Figure 5, +15V can be converted (via +7.5V and –7.5V) to a nominal – 15V, though with rather high series resistance (~250Ω). V + + 50 µF R L1 V = OUT + – V –V 2 50 µF 1 8 2 7 100 kΩ + 1 MΩ 3 – 4 R TC7660 6 5 L2 50 µF + – V – Figure 11. Splitting a Supply in Half © 2001 Microchip Technology Inc. DS21465A 9 TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 PACKAGE DIMENSIONS 8-Pin CerDIP .110 (2.79) .090 (2.29) PIN 1 .300 (7.62) .230 (5.84) .020 (0.51) MIN. .055 (1.40) MAX. .320 (8.13) .290 (7.37) .400 (10.16) .370 (9.40) .040 (1.02) .020 (0.51) .200 (5.08) .160 (4.06) .150 (3.81) MIN. .200 (5.08) .125 (3.18) .015 (0.38) .008 (0.20) 3° MIN. .400 (10.16) .320 (8.13) .065 (1.65) .020 (0.51) .045 (1.14) .016 (0.41) 8-Pin Plastic DIP PIN 1 .260 (6.60) .240 (6.10) .045 (1.14) .030 (0.76) .070 (1.78) .040 (1.02) .310 (7.87) .290 (7.37) .400 (10.16) .348 (8.84) .200 (5.08) .140 (3.56) .040 (1.02) .020 (0.51) .150 (3.81) .115 (2.92) .110 (2.79) .090 (2.29) .015 (0.38) .008 (0.20) 3° MIN. .400 (10.16) .310 (7.87) .022 (0.56) .015 (0.38) Dimensions: inches (mm) TC7660-7 9/30/96 10 © 2001 Microchip Technology Inc. DS21465A CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 PACKAGE DIMENSIONS (CONT.) 8-Pin SOIC .157 (3.99) .150 (3.81) .244 (6.20) .228 (5.79) .050 (1.27) TYP. .197 (5.00) .189 (4.80) .069 (1.75) .053 (1.35) .010 (0.25) .007 (0.18) 8° MAX. .020 (0.51) .010 (0.25) .013 (0.33) .004 (0.10) .050 (1.27) .016 (0.40) Dimensions: inches (mm) © 2001 Microchip Technology Inc. DS21465A 11 TC7660-7 9/30/96 CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER TC7660 WORLDWIDE SALES AND SERVICE AMERICAS New York Corporate Office 150 Motor Parkway, Suite 202 Hauppauge, NY 11788 Tel: 631-273-5305 Fax: 631-273-5335 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com Rocky Mountain 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7966 Fax: 480-792-7456 ASIA/PACIFIC (continued) San Jose Microchip Technology Inc. 2107 North First Street, Suite 590 San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955 Singapore Microchip Technology Singapore Pte Ltd. 200 Middle Road #07-02 Prime Centre Singapore, 188980 Tel: 65-334-8870 Fax: 65-334-8850 Taiwan Atlanta 6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 500 Sugar Mill Road, Suite 200B Atlanta, GA 30350 Tel: 770-640-0034 Fax: 770-640-0307 Microchip Technology Taiwan 11F-3, No. 207 Tung Hua North Road Taipei, 105, Taiwan Tel: 886-2-2717-7175 Fax: 886-2-2545-0139 ASIA/PACIFIC Austin EUROPE China - Beijing Australia Analog Product Sales 8303 MoPac Expressway North Suite A-201 Austin, TX 78759 Tel: 512-345-2030 Fax: 512-345-6085 Boston 2 Lan Drive, Suite 120 Westford, MA 01886 Tel: 978-692-3848 Fax: 978-692-3821 Boston Analog Product Sales Unit A-8-1 Millbrook Tarry Condominium 97 Lowell Road Concord, MA 01742 Tel: 978-371-6400 Fax: 978-371-0050 Toronto Microchip Technology Beijing Office Unit 915 New China Hong Kong Manhattan Bldg. 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No licenses are conveyed, implicitly or otherwise, except as maybe explicitly expressed herein, under any intellectual property rights. The Microchip logo and name are registered trademarks of Microchip Technology Inc. in the U.S.A. and other countries. All rights reserved. All other trademarks mentioned herein are the property of their respective companies. TC7660-7 9/30/96 12 © 2001 Microchip Technology Inc. DS21465A