TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 D D D D D D D D D D D D Optimized for Off-Line and dc-to-dc Converters Low Start-Up Current (<1 mA) Automatic Feed-Forward Compensation Pulse-by-Pulse Current Limiting Enhanced Load-Response Characteristics Undervoltage Lockout With Hysteresis Double-Pulse Suppression High-Current Totem-Pole Output Internally Trimmed Bandgap Reference 500-kHz Operation Error Amplifier With Low Output Resistance Designed to Be Interchangeable With UC2842 and UC3842 Series description D PACKAGE (TOP VIEW) COMP NC VFB NC ISENSE NC RT/CT 1 14 2 13 3 12 4 11 5 10 6 9 7 8 REF NC VCC VC OUTPUT GND POWER GROUND NC – No internal connection D-8 OR P PACKAGE (TOP VIEW) COMP VFB ISENSE RT/CT 1 8 2 7 3 6 4 5 REF VCC OUTPUT GND The TL284x and TL384x series of control integrated circuits provide the features that are necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes with a minimum number of external components. Some of the internally implemented circuits are an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator (which also provides current-limit control), and a totem-pole output stage designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state. Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges. Typical UVLO thresholds of 16 V (on) and 10 V (off) on the TLx842 and TLx844 devices make them ideally suited to off-line applications. The corresponding typical thresholds for the TLx843 and TLx845 devices are 8.4 V (on) and 7.6 V (off). The TLx842 and TLx843 devices can operate to duty cycles approaching 100%. A duty-cycle range of 0 to 50% is obtained by the TLx844 and TLx845 by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle. The TL284x-series devices are characterized for operation from –40°C to 85°C. The TL384x-series devices are characterized for operation from 0°C to 70°C. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 1999, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 AVAILABLE OPTIONS PACKAGED DEVICES TA CHIP FORM (Y) SMALL OUTLINE (D) SMALL OUTLINE (D-8) PLASTIC DIP (P) 0°C to 70°C TL3842D TL3843D TL3844D TL3845D TL3842D-8 TL3843D-8 TL3844D-8 TL3845D-8 TL3842P TL3843P TL3844P TL3845P TL3842Y TL3843Y TL3844Y TL3845Y –40°C to 85°C TL2842D TL2843D TL2844D TL2845D TL2842D-8 TL2843D-8 TL2844D-8 TL2845D-8 TL2842P TL2843P TL2844P TL2845P – – – – The D and D-8 packages are available taped and reeled. Add the suffix R to the device type (i.e., TL3842DR or TL3842DR-8). Chip forms are tested at 25°C. functional block diagram VCC 12 34 V NOM GND UVLO 9 – 5-V REF EN + 14 REF Internal Bias Vref Good Logic RT/CT 7 11 10 OSC VC OUTPUT † T Error Amplifier VFB COMP ISENSE 3 1 + – S 2R R R 1V 5 CurrentSense Comparator † The toggle flip-flop is present only in TL2844, TL2845, TL3844, and TL3845. Pin numbers shown are for the D Package. 2 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 PWM Latch POWER GROUND TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage (see Note 1) (ICC < 30 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self limiting Analog input voltage range, VI (VFB and ISENSE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 6.3 V Output voltage, VO (OUTPUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 V Input voltage, VI, (VC, D package only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 V Supply current, ICC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mA Output current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 A Error amplifier output sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA Package thermal impedance, θJA (see Notes 2 and 3): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86°C/W D-8 package . . . . . . . . . . . . . . . . . . . . . . . . . . 97°C/W P package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85°C/W Virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 150°C Output energy (capacitive load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 µJ Lead temperature, 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C † 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 under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTES: 1. All voltages are with respect to the device GND terminal. 2. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can impact reliability. 3. The package thermal impedance is calculated in accordance with JESD 51. recommended operating conditions MIN NOM Supply voltage, VCC and VC‡ MAX UNIT 30 V Input voltage, VI, RT/CT 0 5.5 V Input voltage, VI, VFB and ISENSE 0 5.5 V 0 30 V –0.1 1 V Output voltage, VO, OUTPUT Output voltage, VO, POWER GROUND‡ Supply current, externally limited, ICC 25 mA Average output current, IO 200 mA Reference output current, IO(ref) –20 mA Oscillator frequency, fosc 500 kHz 0 100 125 °C TL284x –40 85 TL384x 0 70 Operating virtual junction temperature, TJ Operating free-air free air temperature, temperature TA °C ‡ These recommended voltages for VC and POWER GROUND apply only to the D package. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 electrical characteristics over recommended operating free-air temperature range, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF (unless otherwise specified) reference section PARAMETER Output voltage TEST CONDITIONS Line regulation IO = 1 mA, VCC = 12 V to 25 V Load regulation IO = 1 mA to 20 mA TA = 25°C TL284x MIN TYP† MAX 4.95 5 5.05 5 5.1 V 6 20 6 20 mV 6 25 6 25 mV 0.2 0.4 0.2 0.4 mV/°C 5.18 V Temperature coefficient of output voltage Output voltage with worst-case variation VCC = 12 V to 25 V, Output noise voltage f = 10 Hz to 10 kHz, Output-voltage long-term drift IO = 1 mA to 20 mA 4.9 5.1 TA = 25°C After 1000 h at TA = 25°C TL384x MIN TYP† 4.9 4.82 50 Short-circuit output current –30 MAX UNIT µV 50 5 25 5 25 mV –100 –180 –30 –100 –180 mA MAX MIN TL384x TYP† MAX 52 57 47 2 10 † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. oscillator section PARAMETER TEST CONDITIONS Oscillator frequency (see Note 5) Frequency change with supply voltage TA = 25°C VCC = 12 V to 25 V MIN TL284x TYP† 47 Frequency change with temperature 50 UNIT 52 57 kHz 2 10 Hz/kHz 50 Hz/kHz Peak-to-peak amplitude at RT/CT 1.7 1.7 V † All typical values are at TA = 25°C. NOTES: 4. Adjust VCC above the start threshold before setting it to 15 V. 5. Output frequency equals oscillator frequency for the TLx842 and TLx843. Output frequency is one-half oscillator frequency for the TLx844 and TLx845. error-amplifier section PARAMETER Feedback input voltage TL284x MIN TYP† COMP at 2.5 V 2.45 VO = 2 V to 4 V 65 90 65 90 dB 0.7 1 0.7 1 MHz 60 70 60 70 dB 2 6 2 6 mA –0.5 –0.8 –0.5 –0.8 mA TEST CONDITIONS Input bias current Open-loop voltage amplification Gain-bandwidth product Supply-voltage rejection ratio Output sink current VCC = 12 V to 25 V VFB at 2.7 V, COMP at 1.1 V Output source current VFB at 2.3 V, COMP at 5 V High-level output voltage VFB at 2.3 V, RL = 15 kΩ to GND Low-level output voltage VFB at 2.7 V, RL = 15 kΩ to GND 5 † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 MAX TL384x MIN TYP† MAX 2.50 2.55 2.42 2.50 2.58 V –0.3 –1 –0.3 –2 µA 6 0.7 5 1.1 6 0.7 UNIT V 1.1 V TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 electrical characteristics over recommended operating free-air temperature range, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF (unless otherwise specified) (continued) current-sense section MAX TL384x MIN TYP† MAX 3 3.13 2.85 3 3.15 V/V 1 1.1 0.9 1 1.1 V –2 –10 µA Delay time to output 150 300 150 † All typical values are at TA = 25°C. NOTES: 4. Adjust VCC above the start threshold before setting it to 15 V. 6. These parameters are measured at the trip point of the latch, with VFB at 0 V. 7. Voltage amplification is measured between ISENSE and COMP, with the input changing from 0 V to 0.8 V. 300 ns PARAMETER TEST CONDITIONS Voltage amplification See Notes 6 and 7 Current-sense comparator threshold COMP at 5 V, See Note 6 Supply-voltage rejection ratio VCC = 12 V to 25 V, See Note 6 TL284x MIN TYP† 2.85 0.9 70 Input bias current –2 70 –10 UNIT dB output section PARAMETER TL284x MIN TYP† TEST CONDITIONS High level output voltage High-level IOH = –20 mA IOH = –200 mA Low level output voltage Low-level IOL = 20 mA IOL = 200 mA Rise time CL = 1 nF, Fall time CL = 1 nF, MAX TL384x MIN TYP† 13 13.5 13 13.5 12 13.5 12 13.5 TA = 25°C TA = 25°C MAX UNIT V 0.1 0.4 0.1 0.4 1.5 2.2 1.5 2.2 50 150 50 150 ns 50 150 50 150 ns V † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. undervoltage-lockout section PARAMETER Start threshold voltage Minimum operating voltage after startup MIN TL284x TYP† MAX MIN TL384x TYP† MAX TLx842, TLx844 15 16 17 14.5 16 17.5 TLx843, TLx845 7.8 8.4 9 7.8 8.4 9 TLx842, TLx844 9 10 11 8.5 10 11.5 TLx843, TLx845 7 7.6 8.2 7 7.6 8.2 MAX MIN UNIT V V † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. pulse-width-modulator section PARAMETER Maximum duty cycle MIN TL284x TYP† TL384x TYP† MAX TLx842, TLx843 95% 97% 100% 95% 97% 100% TLx844, TLx845 46% 48% 50% 46% 48% 50% Minimum duty cycle 0 UNIT 0 † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 electrical characteristics over recommended operating free-air temperature range, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF (unless otherwise specified) (continued) supply voltage PARAMETER TEST CONDITIONS MIN TL284x TYP† Start-up current MAX MIN TL384x TYP† MAX UNIT 0.5 1 0.5 1 mA Operating supply current VFB and ISENSE at 0 V 11 17 11 17 mA Limiting voltage ICC = 25 mA 34 34 V † All typical values are at TA = 25°C. NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. electrical characteristics, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF, TA = 25°C (unless otherwise specified) reference section PARAMETER Output voltage TEST CONDITIONS TL384xY MIN TYP MAX UNIT IO = 1 mA VCC = 12 V to 25 V 5 V Line regulation 6 mV Load regulation IO = 1 mA to 20 mA 6 mV Temperature coefficient of output voltage Output noise voltage f = 10 Hz to 10 kHz Output-voltage long-term drift After 1000 h at TA = 25°C Short-circuit output current 0.2 mV/°C 50 µV 5 mV –100 mA NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. oscillator section PARAMETER TEST CONDITIONS Oscillator frequency (see Note 5) Frequency change with supply voltage VCC = 12 V to 25 V Frequency change with temperature Peak-to-peak amplitude at RT/CT TL384xY MIN TYP MAX UNIT 52 kHz 2 Hz/kHz 5 Hz/kHz 1.7 V NOTES: 4. Adjust VCC above the start threshold before setting it to 15 V. 5. Output frequency equals oscillator frequency for the TLx842 and TLx843. Output frequency is one-half oscillator frequency for the TLx844 and TLx845. 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 electrical characteristics, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF, TA= 25°C (unless otherwise specified) (continued) error-amplifier section PARAMETER Feedback input voltage TEST CONDITIONS TL384xY MIN COMP at 2.5 V Input bias current Open-loop voltage amplification TYP UNIT 2.50 V –0.3 µA VO = 2 V to 4 V Gain-bandwidth product Supply-voltage rejection ratio MAX 90 dB 1 MHz Output sink current VCC = 12 V to 25 V VFB at 2.7 V, COMP at 1.1 V 70 dB 6 mA Output source current VFB at 2.3 V, COMP at 5 V –0.8 mA High-level output voltage VFB at 2.3 V, RL = 15 kΩ to GND 6 V Low-level output voltage VFB at 2.7 V, RL = 15 kΩ to GND 0.7 V NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. current-sense section PARAMETER TEST CONDITIONS TL384xY MIN TYP MAX 3 UNIT Voltage amplification See Notes 6 and 7 Current-sense comparator threshold COMP at 5 V, See Note 6 1 V Supply-voltage rejection ratio VCC = 12 V to 25 V, See Note 6 70 dB –2 µA 150 ns Input bias current Delay time to output V/V NOTES: 4. Adjust VCC above the start threshold before setting it to 15 V. 6. These parameters are measured at the trip point of the latch, with VFB at 0 V. 7. Voltage amplification is measured between ISENSE and COMP, with the input changing from 0 V to 0.8 V. output section PARAMETER TEST CONDITIONS TL384xY MIN TYP MAX 13.5 UNIT High level output voltage High-level IOH = –20 mA IOH = –200 mA Low level output voltage Low-level IOL = 20 mA IOL = 200 mA 0.1 Rise time CL = 1 nF 50 ns Fall time CL = 1 nF NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. 50 ns V 13.5 V 1.5 undervoltage-lockout section TL384xY PARAMETER MIN Start threshold voltage Minimum operating voltage after startup TYP TL3842Y, TL3844Y 16 TL3843Y, TL3845Y 8.4 TL3842Y, TL3844Y 10 TL3843Y, TL3845Y 7.6 MAX UNIT V V NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 electrical characteristics, VCC = 15 V (see Note 4), RT = 10 kΩ, CT = 3.3 nF, TA = 25°C (unless otherwise specified) (continued) pulse-width-modulator section TL384xY PARAMETER MIN Maximum duty cycle TYP TL3842Y, TL3843Y 97% TL3844Y, TL3845Y 48% MAX UNIT NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. supply voltage PARAMETER TEST CONDITIONS Start-up current Operating supply current VFB and ISENSE at 0 V Limiting voltage ICC = 25 mA NOTE 4: Adjust VCC above the start threshold before setting it to 15 V. 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL384xY MIN UNIT TYP MAX 0.5 1 mA 11 17 mA 34 V TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 APPLICATION INFORMATION 2.5 V 0.5 mA Error Amplifier COMP Zf NOTE A: + – VFB Zi Error amplifier can source or sink up to 0.5 mA. Figure 1. Error-Amplifier Configuration Error Amplifier IS (see Note A) 2R + – R COMP Rf RS 1V Current-Sense Comparator ISENSE Cf GND NOTE A: Peak current (IS) is determined by the formula: 1 V I S(max) RS A small RC filter formed by resistor Rf and capacitor Cf may be required to suppress switch transients. + Figure 2. Current-Sense Circuit REF RT (see Note A) RT/CT CT GND NOTE A: For RT > 5 kΩ: f [ R1.72C T T Figure 3. Oscillator Section POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 APPLICATION INFORMATION TIMING RESISTANCE vs FREQUENCY DEAD TIME vs TIMING CAPACITANCE 100 100 CT = 10 nF VCC = 15 V RT ≥ 5 kΩ TA = 25°C 40 CT = 4.7 nF CT = 22 nF R T – Timing Resistance – kΩ Dead Time – µ s 40 10 4 1 CT = 1 nF CT = 22 nF 10 CT = 47 nF CT = 100 nF 4 0.4 VCC = 15 V TA = 25°C 1 100 0.1 0 4 10 40 100 1k 10 k 100 k 1M f - Frequency - Hz CT – Timing Capacitance – nF Figure 4 Figure 5 open-loop laboratory test fixture In the open-loop laboratory test fixture shown in Figure 6, high peak currents associated with loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to the GND terminal in a single-point ground. The transistor and 5-kΩ potentiometer sample the oscillator waveform and apply an adjustable ramp to the ISENSE terminal. REF RT A 4.7 kΩ VCC 2N2222 100 kΩ 1 kΩ Error Amplifier Adjust DUT VFB 5 kΩ REF COMP ISENSE 0.1 µF TL284x TL384x VCC OUTPUT 0.1 µF 1 kΩ, 1 W OUTPUT 4.7 kΩ ISENSE Adjust RT/CT GND GND CT Figure 6. Open-Loop Laboratory Test Fixture 10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL284x, TL384x CURRENT-MODE PWM CONTROLLERS SLVS038E – JANUARY 1989 – REVISED DECEMBER 1999 APPLICATION INFORMATION shutdown technique The PWM controller (see Figure 7) can be shut down by two methods: either raise the voltage at ISENSE above 1 V or pull the COMP terminal below a voltage two diode drops above ground. Either method causes the output of the PWM comparator to be high (refer to block diagram). The PWM latch is reset dominant so that the output remains low until the next clock cycle after the shutdown condition at the COMP or ISENSE terminal is removed. In one example, an externally latched shutdown can be accomplished by adding an SCR that resets by cycling VCC below the lower UVLO threshold. At this point, the reference turns off, allowing the SCR to reset. 1 kΩ REF COMP Shutdown 330 Ω ISENSE 500 Ω Shutdown To Current-Sense Resistor Figure 7. Shutdown Techniques A fraction of the oscillator ramp can be resistively summed with the current-sense signal to provide slope compensation for converters requiring duty cycles over 50% (see Figure 8). Note that capacitor C forms a filter with R2 to suppress the leading-edge switch spikes. REF 0.1 µF RT RT/CT CT R1 ISENSE R2 ISENSE C RSENSE Figure 8. Slope Compensation POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 1999, Texas Instruments Incorporated