UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 Low Power Economy BiCMOS Current Mode PWM FEATURES DESCRIPTION 100µA Typical Starting Supply Current 500µA Typical Operating Supply Current Operation to 1MHz Internal Soft Start Internal Fault Soft Start Internal Leading-Edge Blanking of the Current Sense Signal 1 Amp Totem-Pole Output 70ns Typical Response from Current-Sense to Gate Drive Output 1.5% Tolerance Voltage Reference Same Pinout as UCC3802, UC3842, and UC3842A The UCC3813-0/-1/-2/-3/-4/-5 family of high-speed, low-power integrated circuits contain all of the control and drive components required for off-line and DC-to-DC fixed frequency current-mode switching power supplies with minimal parts count. These devices have the same pin configuration as the UC3842/3/4/5 family, and also offer the added features of internal full-cycle soft start and internal leading-edge blanking of the current-sense input. The UCC3813-0/-1/-2/-3/-4/-5 family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of critical voltage levels. Lower reference parts such as the UCC3813-3 and UCC3813-5 fit best into battery operated systems, while the higher reference and the higher UVLO hysteresis of the UCC3813-2 and UCC3813-4 make these ideal choices for use in off-line power supplies. The UCC2813-x series is specified for operation from –40°C to +85°C and the UCC3813-x series is specified for operation from 0°C to +70°C. ORDERING INFORMATION Part Number UCCx813-0 UCCx813-1 UCCx813-2 UCCx813-3 UCCx813-4 UCCx813-5 Maximum Duty Cycle 100% 50% 100% 100% 50% 50% Reference Voltage 5V 5V 5V 4V 5V 4V Turn-On Threshold 7.2V 9.4V 12.5V 4.1V 12.5V 4.1V Turn-Off Threshold 6.9V 7.4V 8.3V 3.6V 8.3V 3.6V BLOCK DIAGRAM UDG-96134 04/99 UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 ABSOLUTE MAXIMUM RATINGS (Note 1) CONNECTION DIAGRAMS VCC Voltage (Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0V VCC Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.0mA OUT Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0A OUT Energy (Capacitive Load) . . . . . . . . . . . . . . . . . . . 20.0µJ Analog Inputs (FB, CS) . . . . . . . . . . . . . . . . . . . . –0.3V to 6.3V Power Dissipation at TA < +25°C (N Package). . . . . . . . . 1.0W Power Dissipation at TA < +25°C (D Package). . . . . . . . 0.65W Storage Temperature . . . . . . . . . . . . . . . . . . . –65 C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . –55 C to +150°C Lead Temperature (Soldering, 10 Seconds). . . . . . . . . +300°C DIL-8 or SOIC-8 (TOP VIEW) N or D PACKAGE Note 1: All voltages are with respect to GND. All currents are positive into the specified terminal. Consult Unitrode Integrated Circuits databook for information regarding thermal specifications and limitations of packages. Note 2: In normal operation VCC is powered through a current limiting resistor. Absolute maximum of 12V applies when VCC is driven from a low impedance source such that ICC does not exceed 30mA. UCC2813 UCC3813 TEMPERATURE RANGE –40°C TO +85°C 0°C TO +70°C 813 1 8 REF FB 2 7 VCC CS 3 6 OUT RC 4 5 GND TSSOP-8 (TOP VIEW) PW PACKAGE PACKAGES N, D, PW N, D, PW ORDERING INFORMATION UCC COMP – 1 COMP REF 8 2 FB VCC 7 3 CS OUT 6 4 RC GND 5 PRODUCT OPTION PACKAGE TEMPERATURE RANGE ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for –40°C ≤ TA ≤ +85°C for UCC2813-x; 0°C ≤ TA ≤ +70°C for UCC3813-x; VCC = 10V (Note 3); RT = 100k from REF to RC; CT=330pF from RC to GND; 0.1µF capacitor from VCC to GND; 0.1µF capacitor from VREF to GND. TA = TJ. PARAMETER UCC2813-x UCC3813-x TEST CONDITIONS MIN UNITS TYP MAX Reference Section Output Voltage Load Regulation Total Variation TJ = +25°C, I = 0.2mA, UCCx813-0/-1/-2/-4 4.925 5.00 5.075 V TJ = +25°C, I = 0.2mA, UCCx813-5 3.94 4.00 4.06 V 10 30 mV 0.2mA < I < 5mA UCCx813 -0-1/-2/-4 (Note 7) 4.84 5.00 5.10 V UCCx813-5 (Note 7) 3.84 4.00 4.08 V Output Noise Voltage 10Hz ≤ f ≤ 10kHz, TJ = +25°C (Note 9) 70 µV Long Term Stability TA = +125 C, 1000 Hours (Note 9) 5 mV Output Short Circuit –5 –35 mA Oscillator Section Oscillator Frequency Temperature Stability UCCx813-0/-1/-2/-4 (Note 4) 40 46 52 kHz UCCx813-5 (Note 4) 26 31 36 kHz 2.25 2.40 (Note 9) 2.5 Amplitude Peak-to-Peak Oscillator Peak Voltage 2.45 2 % 2.55 V V UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for –40°C ≤ TA ≤ +85°C for UCC2813-x; 0°C ≤ TA ≤ +70°C for UCC3813-x; VCC = 10V (Note 3); RT = 100k from REF to RC; CT=330pF from RC to GND; 0.1µF capacitor from VCC to GND; 0.1µF capacitor from VREF to GND. TA = TJ. PARAMETER UCC2813-x UCC3813-x TEST CONDITIONS UNITS MIN TYP MAX COMP = 2.5V; UCCx813-0/-1/-2/-4 2.42 2.50 2.56 COMP = 2.0V; UCCx813-3/-5 1.92 2.0 2.05 V 2 µA 2.5 mA Error Amplifier Section Input Voltage –2 Input Bias Current Open Loop Voltage Gain COMP Sink Current 60 FB = 2.7V, COMP = 1.1V 0.4 COMP Source Current FB = 1.8V, COMP = REF – 1.2V –0.2 Gain Bandwidth Product (Note 9) 80 –0.5 V dB –0.8 2 mA MHz PWM Section Maximum Duty Cycle Minimum Duty Cycle UCCx813-0/-2/-3 97 99 100 UCCx813-1/-4/-5 48 49 50 COMP = 0V % 0 % 1.80 V/V Current Sense Section Gain (Note 5) Maximum Input Signal COMP = 5V (Note 6) 1.65 0.9 1.0 –200 Input Bias Current CS Blank Time Over-Current Threshold COMP to CS Offset 1.10 CS = 0V 1.1 V 200 nA 50 100 150 ns 1.32 1.55 1.70 V 0.45 0.90 1.35 V Output Section OUT Low Level OUT High VSAT (VCC-OUT) I = 20mA, all parts 0.1 0.4 V I = 200mA, all parts 0.35 0.90 V I = 50mA, VCC = 5V, UCCx813-3/-5 0.15 0.40 V I = 20mA, VCC = 0V, all parts 0.7 1.2 V I = –20mA, all parts 0.15 0.40 V I = –200mA, all parts 1.0 1.9 V I = –50mA,VCC = 5V, UCCx813-3/-5 0.4 0.9 V Rise Time CL = 1nF 41 70 ns Fall Time CL = 1nF 44 75 ns 7.2 7.8 V Undervoltage Lockout Section Start Threshold (Note 8) Stop Threshold (Note 8) Start to Stop Hysteresis UCCx813-0 6.6 UCCx813-1 8.6 9.4 10.2 V UCCx813-2/-4 11.5 12.5 13.5 V UCCx813-3/-5 3.7 4.1 4.5 V UCC1813-0 6.3 6.9 7.5 V UCC1813-1 6.8 7.4 8.0 V UCCx813-2/-4 7.6 8.3 9.0 V UCCx813-3/-5 3.2 3.6 4.0 V UCCx813-0 0.12 0.3 0.48 V UCCx813-1 1.6 2 2.4 V UCCx813-2/-4 3.5 4.2 5.1 V UCCx813-3/-5 0.2 0.5 0.8 V 3 UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for –40°C ≤ TA ≤ +85°C for UCC2813-x; 0°C ≤ TA ≤ +70°C for UCC3813-x; VCC = 10V (Note 3); RT = 100k from REF to RC; CT=330pF from RC to GND; 0.1µF capacitor from VCC to GND; 0.1µF capacitor from VREF to GND. TA = TJ. PARAMETER UCC2813-x UCC3813-x TEST CONDITIONS MIN TYP UNITS MAX Soft Start Section COMP Rise Time FB = 1.8V, Rise from 0.5V to REF–1V 4 ms Overall Section Start-up Current VCC < Start Threshold 0.1 0.23 mA Operating Supply Current FB = 0V, CS = 0V, RC = 0V 0.5 1.2 mA VCC Internal Zener Voltage ICC = 10mA (Note 8) 12 13.5 15 V VCC Internal Zener Voltage Minus Start Threshold Voltage UCCx813-2/-4 0.5 1.0 V Note 3: Adjust VCC above the start threshold before setting at 10V. Note 4: Oscillator frequency for the UCCx813-0, UCCx813-2 and UCCx813-3 is the output frequency. Oscillator frequency for the UCCx813-1, UCCx813-4 and UCCx813-5 is twice the output frequency. VCOMP Note 5: Gain is defined by: A 0 ≤ VCS ≤ 0.8V . VCS Note 6: Parameter measured at trip point of latch with Pin 2 at 0V. Note 7: Total Variation includes temperature stability and load regulation. Note 8: Start Threshold, Stop Threshold and Zener Shunt Thresholds track one another. Note 9: Guaranteed by design. Not 100% tested in production. PIN DESCRIPTIONS sense comparator during the 100ns interval immediately following the rising edge of the OUT pin. This digital filtering, also called leading-edge blanking, means that in most applications, no analog filtering (RC filter) is required on CS. Compared to an external RC filter technique, the leading-edge blanking provides a smaller effective CS to OUT propagation delay. Note, however, that the minimum non-zero On-Time of the OUT signal is directly affected by the leading-edge-blanking and the CS to OUT propagation delay. COMP: COMP is the output of the error amplifier and the input of the PWM comparator. Unlike other devices, the error amplifier in the UCC3813 family is a true, low output-impedance, 2MHz operational amplifier. As such, the COMP terminal can both source and sink current. However, the error amplifier is internally current limited, so that you can command zero duty cycle by externally forcing COMP to GND. The UCC3813 family features built-in full cycle Soft Start. Soft Start is implemented as a clamp on the maximum COMP voltage. The over-current comparator is only intended for fault sensing, and exceeding the over-current threshold will cause a soft start cycle. FB: FB is the inverting input of the error amplifier. For best stability, keep FB lead length as short as possible and FB stray capacitance as small as possible. RC: RC is the oscillator timing pin. For fixed frequency operation, set timing capacitor charging current by connecting a resistor from REF to RC. Set frequency by connecting a timing capacitor from RC to GND. For best performance, keep the timing capacitor lead to GND as short and direct as possible. If possible, use separate ground traces for the timing capacitor and all other functions. CS: CS is the input to the current sense comparators. The UCC3813 family has two different current sense comparators: the PWM comparator and an over-current comparator. The UCC3813 family contains digital current sense filtering, which disconnects the CS terminal from the current 4 UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 PIN DESCRIPTIONS (cont.) low, total supply current will be higher, depending on OUT current. Total VCC current is the sum of quiescent VCC current and the average OUT current. Knowing the operating frequency and the MOSFET gate charge (Qg), average OUT current can be calculated from: The frequency of oscillation can be estimated with the following equations: UCCx813-0/-1/-2/-4: F = 1.5 R •C UCCx813-3, UCCx813-5: F = 1.0 R •C IOUT = Q g • F . To prevent noise problems, bypass VCC to GND with a ceramic capacitor as close to the VCC pin as possible. An electrolytic capacitor may also be used in addition to the ceramic capacitor. where frequency is in Hz, resistance is in Ω, and capacitance is in farads. The recommended range of timing resistors is between 10k and 200k and timing capacitor is 100pF to 1000pF. Never use a timing resistor less than 10k. REF: REF is the voltage reference for the error amplifier and also for many other functions on the IC. REF is also used as the logic power supply for high speed switching logic on the IC. GND: GND is reference ground and power ground for all functions on this part. OUT: OUT is the output of a high-current power driver capable of driving the gate of a power MOSFET with peak currents exceeding ±750mA. OUT is actively held low when VCC is below the UVLO threshold. The high-current power driver consists of FET output devices, which can switch all of the way to GND and all of the way to VCC. The output stage also provides a very low impedance to overshoot and undershoot. This means that in many cases, external schottky clamp diodes are not required. When VCC is greater than 1V and less than the UVLO threshold, REF is pulled to ground through a 5kΩ resistor. This means that REF can be used as a logic output indicating power system status. It is important for reference stability that REF is bypassed to GND with a ceramic capacitor as close to the pin as possible. An electrolytic capacitor may also be used in addition to the ceramic capacitor. A minimum of 0.1µF ceramic is required. Additional REF bypassing is required for external loads greater than 2.5mA on the reference. VCC: VCC is the power input connection for this device. In normal operation VCC is powered through a current limiting resistor. Although quiescent VCC current is very To prevent noise problems with high speed switching transients, bypass REF to ground with a ceramic capacitor very close to the IC package. APPLICATION INFORMATION UDG-96139 The UCC3813-0/-1/-2/-3/-4/-5 oscillator generates a sawtooth waveform on RC. The rise time is set by the time constant of RT and CT. The fall time is set by CT and an internal transistor on-resistance of approximately 125Ω. During the fall time, the output is off and the maximum duty cycle is reduced below 50% or 100% depending on the part number. Larger timing capacitors increase the discharge time and reduce the maximum duty cycle and frequency. Figure 1. Oscillator. 5 UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 APPLICATION INFORMATION (cont.) 4.00 3.98 3.96 VREF (V) 3.94 3.92 3.90 3.88 3.86 3.84 3.82 4 Figure 2. Error amplifier gain/phase response. 4.4 4.6 4.8 5 5.2 VCC (V) 5.4 5.6 5.8 Figure 5. UCC3813-3/-5 VREF vs. VCC; ILOAD = 0.5mA. 1000 Oscillator Freq. (kHz) 1000 Oscillator Freq. (kHz) 4.2 10 0p F 100 20 0p 33 F 0p F 100 10 0p F 20 0p F 33 0p F 1n F 1n 10 F 10 10 100 1000 10 RT (k ) 1000 RT (k ) Figure 3. UCC3813-0/-1/-2/-4 oscillator frequency vs. RT and CT. Figure 6. UCC3813-3/-5 oscillator frequency vs. RT and CT. 50 100 99.5 pF 00 pF 00 30 =3 pF 48 =1 48.5 =2 96.5 CT pF 00 pF 97 pF 30 =3 00 =2 CT 97.5 =1 98 49 CT CT 98.5 CT Maximum Duty Cycle (%) 49.5 99 CT Maximum Duty Cycle (%) 100 47.5 96 47 95.5 46.5 95 10 100 10 1000 100 Oscillator Frequency (kHz) Oscillator Frequency (kHz) Figure 4. UCC3813-0/-2/-3 max. duty cycle vs. oscillator frequency. Figure 7. UCC3813-1/-4/-5 max. duty cycle vs. oscillator frequency. 6 1000 6 UCC2813-0/-1/-2/-3/-4/-5 UCC3813-0/-1/-2/-3/-4/-5 APPLICATION INFORMATION (cont.) 16 8 14 7 12 , 0V C VC C =1 F 8 C VC VC 5 ICC (mA) ICC (mA) 10 nF 1 V, 6 F 1n n V, 1 =8 6 nF 1 V, 4 CC 3 Loa 0V, No C=1 2 No Load VCC = 8V, 1 VC 2 0 0 100 200 300 400 500 600 700 800 0 0 900 1000 =8 V d 4 0 =1 VCC = d o Loa 10V, N d , No Loa VCC = 8V 100 200 Oscillator Frequency (kHz) 300 400 500 600 700 800 900 1000 Oscillator Frequency (kHz) Figure 8. UCC3813-0 ICC vs. oscillator frequency. Figure 10. UCC3813-5 ICC vs. oscillator frequency. 1.1 500 450 COMP to CS Offset (Volts) UCC1803/5 Dead Time (ns) 400 350 300 250 UCC1800/1/2/4 200 150 100 50 200 300 400 500 600 700 800 900 0.9 0.8 1000 CT (pF) Slope = 1.8mV/°C 0.7 0.6 0 -55-50 0 100 1.0 -25 0 25 50 75 100 Temperature (°C) Figure 9. Dead time vs. CT, RT = 100k. Figure 11. COMP to CS offset vs. temperature, CS = 0V. UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460 7 125 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. 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