SLUS458B – AUGUST 2001 FEATURES D D D D D D D D D DESCRIPTION 1-MHz Operation 50-µA Start-Up Current, 100-µA Maximum Low Operating Current of 2.3 mA at 52 kHz 50-ns Cycle-by-Cycle Overcurrent Limiting ±1-A Peak Output Current Rail-to-Rail Output Swings with 25-ns Rise and 20-ns Fall Times ±1% Initial Trimmed 2.5-V Error Amplifier Reference Trimmed Oscillator Discharge Current MSOP-8 Package Minimizes Board Space UCC38C4x family is a high-performance currentmode PWM controller. It is an enhanced BiCMOS version with pin-for-pin compatibility to the industry standard UC384xA family and UC384x family of PWM controllers. In addition, lower startup voltage versions of 7 V are offered as UCC38C40 and UCC38C41. Providing necessary features to control fixed frequency, peak current-mode power supplies, this family offers the following performance advantages. The device offers high-frequency operation up to 1 MHz with low start-up and operating currents, thus minimizing start-up loss and low operating power consumption for improved efficiency. The device also features a very fast current-sense-to-output delay time of 50 ns and a ±1 A peak output current capability with improved rise and fall times for driving large external MOSFETs directly. APPLICATIONS D Switch-Mode Power Supplies D dc-to-dc Converters D Board Mount Power Modules The UCC38C4x family is offered in 8-pin packages, MSOP (DGK), SOIC (D) and PDIP (P). FUNCTIONAL BLOCK DIAGRAM VREF UVLO + 7 VDD 5 GND 6 OUT + 5.0 V VREF 8 VREF GOOD LOGIC RT/CT 4 OSC (NOTE) 2.5 V FB + ERROR AMP T 2R S Q 2 R 1V COMP 1 CS R Q 3 Note: Toggle flip–flop used only in UCC38C41, UCC38C44, and UCC38C45. UDG–99139 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 2001, Texas Instruments Incorporated !" # $%&" !# '%()$!" *!"&+ *%$"# $ " #'&$$!"# '& ",& "& # &-!# #"% &"# #"!*!* .!!"/+ *%$" '$&##0 *&# " &$&##!)/ $)%*& "&#"0 !)) '!! &"&#+ www.ti.com 1 SLUS458B – AUGUST 2001 recommended operating conditions MIN MAX UNIT Input voltage, VDD 18 Output voltage range, VOUT 18 V 200 mA –20 mA 150 °C Average output current, IOUTW Reference output current, IOUT(ref)W Operating junction temperature, TJW –55 V ¶ It is not recommended that the device operate under conditions beyond those specified in this table for extended periods of time. absolute maximum ratings over operating free-air temperature (unless otherwise noted)}w Supply voltage (VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 V Output current, IOUT peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 A Output energy, capacitive load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 µJ Voltage rating (COMP, CS, FB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 6.3 V (OUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 20 V (RT/CT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 6.3 V (VREF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Error amplifier output sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA Total Power Dissipation at TA = 25°C: D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 mW DGK package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 mW P package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 mW Operating junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C Storage temperature range Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°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. § All voltages are with respect to ground. Currents are positive into and negative out of the specified terminals. Consult the Packaging Section of the Databook for thermal limitations and considerations of the package. AVAILABLE OPTIONS TA MAXIMUM DUTY CYCLE 100% –40°C 40°C to 85°C 50% 100% 0°C 0 C to 70°C 70 C 50% UVLO ON/OFF SOIC–8 SMALL OUTLINE (D) PDIP–8 PLASTIC DIP (P) MSOP–8 SMALL OUTLINE (DGK) 14.5V / 9.0V UCC28C42D UCC28C42P UCC28C42DGK 8.4V / 7.6V UCC28C43D UCC28C43P UCC28C43DGK 7.0V / 6.6V UCC28C40D UCC28C40P UCC28C40DGK 14.5V / 9.0V UCC28C44D UCC28C44P UCC28C44DGK 8.4V / 7.6V UCC28C45D UCC28C45P UCC28C45DGK 7.0V / 6.6V UCC28C41D UCC28C41P UCC28C41DGK 14.5V / 9.0V UCC38C42D UCC38C42P UCC38C42DGK 8.4V / 7.6V UCC38C43D UCC38C43P UCC38C43DGK 7.0V / 6.6V UCC38C40D UCC38C40P UCC38C40DGK 14.5V / 9.0V UCC38C44D UCC38C44P UCC38C44DGK 8.4V / 7.6V UCC38C45D UCC38C45P UCC38C45DGK 7.0V / 6.6V UCC38C41D UCC38C41P UCC38C41DGK † D (SOIC–8) and DGK (MSOP–8) packages are available taped and reeled. Add R suffix to device type (e.g. UCC28C42DR) to order quantities of 2500 devices per reel. Tube quantities are 75 for D packages (SOIC–8) and 80 for DGK package (MSOP–8), and 50 for P package (PDIP-8). 2 www.ti.com SLUS458B – AUGUST 2001 electrical characteristics VDD = 15 V (See Note 1), RT = 10 kΩ, CT = 3.3 nF, CVDD = 0.1µF and no load on the outputs, TA = –40°C to 85°C for the UCC28C4x and TA = 0°C to 70°C for the UCC38C4x, TA = TJ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Reference Section Output voltage, initial accuracy Line regulation TA = 25°C IOUT = 1mA VDD = 12 V to 18 V Load regulation 1mA to 20mA Temperature stability See Note 2 Total output variation See Note 2 Output noise voltage 10 Hz to 10 kHz, Long term stability 1000 hours, 4.9 5.0 5.1 V 2 20 mV 1 25 mV 0.4 mV/°C 0.2 4.82 TA = 25°C, TA = 125°C, See Note 2 –30 V µV 50 See Note 2 Output short circuit 5.18 5 25 mV –45 –55 mA 52 55 kHz 0.2% 1.0% Oscillator Section Initial accuracy Voltage stability Temperature stability Amplitude Discharge current TA = 25°C, See Note 3 VDD = 12 V to 18 V 49 TMIN to TMAX, See Note 2 RT/CT Pin peak-to-peak TA = 25°C, RT/CT = 2 V, RT/CT = 2 V, 5 % 1.9 See Note 4 See Note 4 V 7.7 8.4 9.0 mA 7.2 8.4 9.5 mA 2.475 2.500 2.525 2.45 2.50 2.55 V –0.1 –2.0 µA Error Amplifier Section Feedback input voltage, initial accuracy Feedback input voltage, total variation Input bias current VCOMP = 2.5 V, VCOMP = 2.5 V, TA = 25°C V Open-loop voltage gain (AVOL) VFB = 5.0 V VOUT = 2 V to 4 V 65 90 dB Unity gain bandwidth See Note 2 1.0 1.5 MHz Power supply rejection ratio (PSRR) VDD = 12 V to 18 V VFB = 2.7 V, VCOMP = 1.1 V 60 2 14 mA –0.5 –1.0 mA 5 6.8 Output sink current Output source current High-level output voltage (VOH) VFB = 2.3 V, VFB = 2.7 V, VCOMP = 5V RLOAD = 15 k to GND Low-level output voltage (VOL) VFB = 2.7 V, RLOAD = 15 k to VREF dB V 0.1 1.1 V 2.85 3.00 3.15 V/V 0.9 1.0 1.1 V –0.1 –2.0 µA 35 70 ns Current Sense Section Gain See Note 5, 6 Maximum input signal VCOMP = 2 V VDD = 12 V to 18 V, See Note 2, 5 Power supply rejection ratio (PSRR) Input bias current CS to output delay COMP to CS offset 70 VCS = 0 V 1.15 Adjust VDD above the start threshold before setting at 15 V. Ensured by design. Not production tested. Output frequencies of the UCC38C41, UCC38C44 and the UCC38C45 are half the oscillator frequency. Oscillator discharge current is measured with RT = 10 kΩ to VREF. Parameter measured at trip point of latch with VFB = 0 V. DV COM , 0V ¬ V ¬ 900mV NOTE: 6. Gain is defined as ACS + CS DV CS NOTE: NOTE: NOTE: NOTE: NOTE: dB V 1. 2. 3. 4. 5. www.ti.com 3 SLUS458B – AUGUST 2001 electrical characteristics VDD = 15 V (See Note 1), RT = 10 kΩ, CT = 3.3 nF, CVDD = 0.1µF and no load on the outputs, TA = –40°C to 85°C for the UCC28C4x and TA = 0°C to 70°C for the UCC38C4x, TA = TJ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Output Section VOUT low (RDS(on) Low) VOUThigh (RDS(on) High) ISINK = 200 mA ISOURCE = 200 mA 5.5 15 10 25 Rise tIme TA = 25°C, TA = 25°C, CLOAD = 1 nF 25 50 CLOAD = 1 nF 20 40 Fall time Ω ns Undervoltage Lockout Section Start threshold Minimum o operating erating voltage UCC38C42, UCC38C44 13.5 14.5 15.5 UCC38C43, UCC38C45 7.8 8.4 9.0 UCC38C40, UCC38C41 6.5 7.0 7.5 UCC38C42, UCC38C44 8 9 10 UCC38C43, UCC38C45 7.0 7.6 8.2 UCC38C40, UCC38C41 6.1 6.6 7.1 UCC38C42, UCC38C43, UCC38C40 94% 96% UCC38C44, UCC38C45, UCC38C41 47% 48% V PWM Section Ma im m duty Maximum d t cycle c cle Minimum duty cycle VFB < 2 V 0% Current Supply Section Start-up current (ISTART-UP) VDD < Undervoltage lockout start threshold VFB = VCS = 0 V Operating supply current (IDD) NOTE 1: 100 µA 2.3 3.0 mA Adjust VDD above the start threshold before setting at 15 V. PDIP (P) PACKAGE (TOP VIEW) COMP FB CS RT/CT 4 50 1 8 2 7 3 4 6 5 SOIC (D) OR MSOP (DGK) PACKAGE (TOP VIEW) COMP FB CS RT/CT VREF VDD OUT GND www.ti.com 1 8 2 7 3 6 4 5 VREF VDD OUT GND SLUS458B – AUGUST 2001 pin assignments COMP: This pin provides the output of the error amplifier for compensation. In addition, the COMP pin is frequently used as a control port by utilizing a secondary-side error amplifier to send an error signal across the secondary-primary isolation boundary through an opto-isolator. CS: The current sense pin is the non-inverting input to the PWM comparator. This is compared to a signal proportional to the error amplifier output voltage. A voltage ramp can be applied to this pin to run the device with a voltage mode control configuration. FB: This pin is the inverting input to the error amplifier. The non-inverting input to the error amplifier is internally trimmed to 2.5 V ±1%. GND: Ground return pin for the output driver stage and the logic level controller section. OUT: The output of the on-chip drive stage. OUT is intended to directly drive a MOSFET. The OUT pin in the UCC38C40, UCC38C42 and UCC38C43 is the same frequency as the oscillator, and can operate near 100% duty cycle. In the UCC38C41, UCC38C44 and the UCC38C45, the frequency of OUT is one-half that of the oscillator due to an internal T flipflop. This limits the maximum duty cycle to < 50%. RT/CT: Timing resistor and timing capacitor. The timing capacitor should be connected to the device ground using minimal trace length. VDD: Power supply pin for the device. This pin should be bypassed with a 0.1-µF capacitor with minimal trace lengths. Additional capacitance may be needed to provide hold up power to the device during startup. VREF: 5-V reference. For stability, the reference should be bypassed with a 0.1-µF capacitor to ground using the minimal trace length possible. www.ti.com 5 SLUS458B – AUGUST 2001 APPLICATION INFORMATION This device is a pin-for-pin replacement of the bipolar UC3842 family of controllers, the industry standard PWM controller for single-ended converters. Familiarity with this controller family is assumed. The UCC28C4x/UCC38C4x series is an enhanced replacement with pin-to-pin compatibility to the bipolar UC284x/UC384x and UC284xA/UC384xA families. The new series offers improved performance when compared to older bipolar devices and other competitive BiCMOS devices with similar functionality. Note that these improvements discussed below generally consist of tighter specification limits that are a subset of the older product ratings, maintaining drop-in capability. In new designs these improvements can be utilized to reduce the component count or enhance circuit performance when compared to the previously available devices. advantages This device increases the total circuit efficiency whether operating off-line or in dc input circuits. In off-line applications the low start-up current of this device reduces steady state power dissipation in the startup resistor, and the low operating current maximizes efficiency while running. The low running current also provides an efficiency boost in battery operated supplies. low voltage operation Two members of the UCC38C4x family are intended for applications that require a lower start-up voltage than the original family members. The UCC38C40 and UCC38C41 have a turn-on voltage of 7.0 V typical and exhibit hysteresis of 0.4 V for a turn-off voltage of 6.6 V. This reduced start-up voltage enables use in systems with lower voltages, such as 12-V battery systems which are nearly discharged. high speed operation The BiCMOS design allows operation at high frequencies that were not feasible in the predecessor bipolar devices. First, the output stage has been redesigned to drive the external power switch in approximately half the time of the earlier devices. Second, the internal oscillator is more robust with less variation as frequency increases. In addition, the current sense to output delay has been reduced by a factor of three, to 45ns typical. These features combine to provide a device capable of reliable high frequency operation. The UCC38C4x family oscillator is true to the curves of the original bipolar devices at lower frequencies yet extends the frequency programmability range to at least 1MHz. This allows the device to offer pin to pin capability where required yet capable of extending the operational range to the higher frequencies typical of latest applications. When the original UC3842 was released in 1984 most switching supplies operated between 20kHz and 100kHz. Today, the UCC38C4x can be used in designs cover a span roughly ten times higher than those numbers. start/run current improvements The start–up current is only 60 µA typical, a significant reduction from the bipolar device’s ratings of 300uA (UC384xA). For operation over the temperature range of –40 to 85°C the UCC28C4x devices offer a maximum startup current of 100 µA, an improvement over competitive BiCMOS devices. This allows the power supply designer to further optimize the selection of the startup resistor value to provide a more efficient design. In applications where low component cost overrides maximum efficiency the low run current of 2.3 mA, typical, may allow the control device to run directly through the single resistor to (+) rail, rather than needing a bootstrap winding on the power transformer, along with a rectifier. The start/run resistor for this case must also pass enough current to allow driving the primary switching MOSFET, which may be a few milliamps in small devices. 6 www.ti.com SLUS458B – AUGUST 2001 APPLICATION INFORMATION ± 1% initial reference voltage The BiCMOS internal reference of 2.5 V has an enhanced design and utilizes production trim to allow initial accuracy of ±1% at room temperature and ± 2% over the full temperature range. This can be used to eliminate an external reference in applications that do not require the extreme accuracy afforded by the additional device. This is very useful for nonisolated dc-to-dc applications where the control device is referenced to the same common as the output. It is also applicable in offline designs that regulate on the primary side of the isolation boundary by looking at a primary bias winding, or perhaps from a winding on the output inductor of a buck-derived circuit. reduced discharge current variation The original UC3842 oscillator did not have trimmed discharged current, and the parameter was not specified on the datasheet. Since many customers attempted to use the discharge current to set a crude deadtime limit the UC3842A family was released with a trimmed discharge current specified at 25°C. The UCC28C4x/UCC38C4x series now offers even tighter control of this parameter, with approximately ±3% accuracy at 25°C, and less than 10% variation over temperature using the UCC28C4x devices. This level of accuracy can enable a meaningful limit to be programmed, a feature not currently seen in competitive BiCMOS devices. The improved oscillator and reference also contribute to decreased variation in the peak to peak variation in the oscillator waveform, which is often used as the basis for slope compensation for the complete power system. soft-start The following diagram provides a typical soft-start circuit for use with the UCC38C42. The values of R and C should be selected to bring the COMP pin up at a controlled rate, limiting the peak current supplied by the power stage. After the soft-start interval is complete the capacitor continues to charge to VREF, effectively removing the PNP transistor from circuit considerations. The optional diode in parallel with the resistor forces a soft-start each time the PWM goes through UVLO and the reference (VREF) goes low. Without the diode,the capacitor otherwise remains charged during a brief loss of supply or brown-out, and no soft-start is enabled upon reapplication of VIN. VREF 8 UCC38C42 COMP 1 GND 5 Figure 1 www.ti.com UDG–01072 7 SLUS458B – AUGUST 2001 APPLICATION INFORMATION oscillator synchronization The UCC38C4x oscillator has the same synchronization characteristics as the original bipolar devices. Thus, the information in the Application Note U–100A, UC3842/3/4/5 Provides Low-Cost Current-Mode Control, (TI Literature No. SLUA143) still applies. The application note describes how a small resistor from the timing capacitor-to-ground can offer an insertion point for synchronization to an external clock, (see Figures 2 and 3). Figure 2 shows how the UCC38C42 can be synchronized to an external clock source. This allows precise control of frequency and dead time with a digital pulse train. 8 VREF 4 RT / CT RT SYNCHRONIZATION CIRCUIT INPUT CT UCC38C42 PWM 24 UDG–01069 Figure 2. Oscillator Synchronization Circuit CLOCK INPUT PWM OUT UPPER THRESHOLD LOW HIGH LOW LOWER THRESHOLD ON . OFF . ON . VCT (ANALOG) OUTPUT A UPPER THRESHOLD VCT LOWER THRESHOLD VSYNC (DIGITAL) COMBINED Figure 3. Synchronization to an External Clock 8 www.ti.com UDG–01070 SLUS458B – AUGUST 2001 APPLICATION INFORMATION precautions The absolute maximum supply voltage is 20 V, including any transients that may be present. If this voltage is exceeded, device damage is likely. This is in contrast to the predecessor bipolar devices, which could survive up to 30 V. Thus, the supply pin should be decoupled as close to the ground pin as possible. Also, since no clamp is included in the device, the supply pin should be protected from external sources which could exceed the 20 V level. Careful layout of the printed board has always been a necessity for high frequency power supplies. As the device switching speeds and operating frequencies increase the layout of the converter becomes increasingly important. This 8-pin device has only a single ground for the logic and power connections. This forces the gate drive current pulses to flow through the same ground that the control circuit uses for reference. Thus, the interconnect inductance should be minimized as much as possible. One implication is to place the device (gate driver) circuitry close to the MOSFET it is driving. Note that this can conflict with the need for the error amplifier and the feedback path to be away from the noise generating components. circuit applications Figure 4 shows a typical off-line application. D50 F1 12 V OUT T1 R10 C52 C3 C12 + AC INPUT 100 Vac – 240 Vac EMI FILTER REQUIRED C55 R56 BR1 D2 R11 C1A L50 D51 C18 5V OUT R12 RT1 C53 C54 D6 R55 C5 SEC COMMON R6 IC2 R50 UCC38C44 1 COMP REF 8 2 FB VCC 7 3 CS OUT 6 4 RT/CT GND 5 R16 Q1 IC2 C50 C13 R50 R53 R52 C51 K IC3 A R R54 UDG–01071 Figure 4. Typical Off-Line Application Figure 5 shows the forward converter with synchronous rectification. This application provides 48 V to 3.3 V at 10 A with over 85% efficiency and uses the UCC38C42 as the secondary-side controller and UCC3961 as the primary-side startup control device. www.ti.com 9 10 www.ti.com 46.4k 0.1uF C5 7 6 5 4 3 2 AGnd Ref Rt FB SS SD OVS R12 200 ucc3961 U1 R2 2 1 C7 8 9 10 11 12 13 14 T2 4 3 R4 1.5k 300 R13 C8 1uF Q2 470pF C6 76.8k R5 R6 4.7 C10 2.7nF 0.1uF C9 R8 R10 1k 5.1k D1 R14 50k R15 20k 40% 0.33 R9 Q1 C22 4.7nF D3 20k R24 20k 402 R25 20k R26 R19 20 4.7 680pF 100 R28 3300pF C12 5.6nF C16 21.5k C23 R17 R16 BAR74 R23 D5 BAR74 Q3 C17 4700pF 1500pF C11 4 3 2 1 4 3 2 1 Vcc DT Rt/Ct CS FB U2 LODR BTLO HIDR 7.5k R18 UCC38C4x PGND 5 6 7 8 C19 470uF 4700pF U4 TPS2832 IN BOOT COMP R27 4.7 10 R21 Q4 GND OUT Vcc REF 5 6 7 8 2uF C26 470uF C20 0.22uF C13 C14 1uF C24 0.1uF D6 BZX84C15LT1 PWRGND 0.1uF C21 3r3V 100 R22 C15 1uF + 100pF Vs CS PGnd Out Vdd St UVS 2.4k R3 1.2k C25 0.047uF R20 10 + R11 0.22uF 10nF 1 + C4 C3 470uF C1 R1 32.4k 10k D2 T1 C18 + VinN VinP R7 1nF C2 L1 4.7uH SLUS458B – AUGUST 2001 APPLICATION INFORMATION Figure 5. Forward Converter with Synchronous Rectification Using the UCC38C42 as the Secondary-Side Controller SLUS458B – AUGUST 2001 TYPICAL CHARACTERISTICS OSCILLATOR FREQUENCY vs TIMING RESISTANCE AND CAPACITANCE OSCILLATOR DISCHARGE CURRENT vs TEMPERATURE 9.5 10 M IDISCH – Oscillator Discharge Current – mA CT = 220 pF CT = 470 pF f – Frequency – Hz 1M CT = 1 nF 100 k 10 k CT = 4.7 nF CT = 2.2 nF 9.0 8.5 8.0 7.5 7.0 1k 1k 10 k 100 k –50 –25 0 Figure 6 1.8 90 180 1.6 160 1.4 80 70 140 60 120 50 100 40 80 30 60 PHASE MARGIN 10 0 1k 10 k 100 k 1M Phase Margin – (°) Gain – (dB) GAIN VREF – Offset Voltage – V 200 100 100 125 COMP to CS OFFSET VOLTAGE vs TEMPERATURE 100 10 75 Figure 7 ERROR AMPLIFIER FREQUENCY RESPONSE 1 50 TJ – Temperature – °C RT – Timing Resistance – 20 25 1.2 1.0 0.8 0.6 40 0.4 20 0.2 0 10 M f – Frequency – Hz 0.0 –50 –25 0 25 50 75 100 125 TJ – Temperature – °C Figure 8 Figure 9 www.ti.com 11 SLUS458B – AUGUST 2001 TYPICAL CHARACTERISTICS REFERENCE VOLTAGE vs TEMPERATURE ERROR AMPLIFIER REFERENCE VOLTAGE vs TEMPERATURE VEAREF – Error Amplifier Reference Voltage – V 5.05 VREF – Reference Voltage – V 5.04 5.03 5.02 5.01 5.00 4.99 4.98 4.97 4.96 4.95 –50 –25 0 25 50 75 100 2.55 2.54 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 2.45 125 –50 –25 TJ – Temperature – °C 0 100 125 ERROR AMPLIFIER INPUT BIAS CURRENT vs TEMPERATURE –35 200 IBIAS – Error Amplifier Input Bias Current – nA ISC – Reference Short Circuit Current – mA 75 Figure 11 REFERENCE SHORT-CIRCUIT CURRENT vs TEMPERATURE –37 –39 –41 –43 –45 –47 –49 –51 –53 150 100 50 0 –50 –100 –150 –200 –25 0 25 50 75 TJ – Temperature – °C 100 125 Figure 12 12 50 TJ – Temperature – °C Figure 10 –55 –50 25 –50 –25 0 25 50 75 TJ – Temperature – °C Figure 13 www.ti.com 100 125 SLUS458B – AUGUST 2001 TYPICAL CHARACTERISTICS UNDERVOLTAGE LOCKOUT vs TEMPERATURE (UCC38C43 & UCC38C45) UNDERVOLTAGE LOCKOUT vs TEMPERATURE (UCC38C42 & UCC38C44) 16 9.0 VUVLO – UVLO Voltage – V 14 13 UVLO ON 12 UVLO OFF 11 10 8.6 8.4 8.2 8.0 7.8 9 7.6 8 7.4 7 7.2 6 –50 UVLO ON 8.8 –25 0 25 50 75 100 125 7.0 –50 UVLO OFF –25 0 TJ – Temperature – °C Figure 14 25 50 75 TJ – Temperature – °C 100 125 Figure 15 UNDERVOLTAGE LOCKOUT vs TEMPERATURE (UCC38C40 & UCC38C41) 7.3 7.2 UVLO ON 7.1 VUVLO – UVLO Voltage – V VUVLO – UVLO Voltage – V 15 7.0 6.9 6.8 6.7 6.6 6.5 UVLO OFF 6.4 6.3 –50 –25 0 25 50 75 100 125 TJ – Temperature – °C Figure 16 www.ti.com 13 SLUS458B – AUGUST 2001 TYPICAL CHARACTERISTICS SUPPLY CURRENT vs TEMPERATURE SUPPLY CURRENT vs OSCILLATOR FREQUENCY 3.0 25 1-nF LOAD 20 2.8 IDD – Supply Current – mA IDD – Supply Current – mA 2.9 15 10 NO LOAD 2.7 2.6 2.5 2.4 NO LOAD 2.3 2.2 5 2.1 2.0 –50 0 0k 200 k 400 k 600 k f – Frequency – Hz 800 k 1M –25 0 Figure 17 40 OUTPUT RISE TIME AND FALL TIME vs TEMPERATURE 75 100 125 MAXIMUM DUTY CYCLE vs OSCILLATOR FREQUENCY 100 10% to 90% VDD = 12 V CT = 220 pF tr (1 nF) 90 30 tf (1 nF) 25 20 10 –50 80 70 CT = 1 nF 60 15 –25 0 25 50 75 100 125 TJ – Temperature – °C 50 0 500 1000 1500 f – Frequency – kHz Figure 19 14 50 Figure 18 Duty Cycle – % Output Rise and Fall TIme – ns 35 25 TJ – Temperature – °C Figure 20 www.ti.com 2000 2500 SLUS458B – AUGUST 2001 TYPICAL CHARACTERISTICS MAXIMUM DUTY CYCLE vs TEMPERATURE MAXIMUM DUTY CYCLE vs TEMPERATURE 100 50 Output Rise and Fall TIme – ns UCC38C40 UCC38C42 UCC38C43 Maximum Duty Cycle – % 98 96 94 92 UCC38C41 UCC38C44 UCC38C45 49 48 47 46 90 –50 –25 0 25 50 75 100 45 –50 125 –25 TJ – Temperature – °C 50 75 100 125 Figure 22 CURRENT SENSE THRESHOLD VOLTAGE vs TEMPERATURE CS TO OUT DELAY TIME vs TEMPERATURE 70 65 1.05 tD – CD to OUT Delay Time – ns VCS_th – Current Sense Threshold – V 25 TJ – Temperature – °C Figure 21 1.10 0 1.00 0.95 60 55 50 45 40 35 0.90 –50 30 –25 0 25 50 75 100 125 TJ – Temperature – °C –50 –25 0 25 50 75 100 125 TJ – Temperature – °C Figure 24 Figure 23 www.ti.com 15 SLUS458B – AUGUST 2001 MECHANICAL DATA D (SOIC) PLASTIC SMALL-OUTLINE PACKAGE Note: UCC38C4x is offered in an 8-pin package ONLY. 14 PINS SHOWN 0.050 (1,27) 0.020 (0,51) 0.014 (0,35) 14 0.010 (0,25) M 8 0.008 (0,20) NOM 0.244 (6,20) 0.228 (5,80) 0.157 (4,00) 0.150 (3,81) Gage Plane 0.010 (0,25) 1 7 0°–ā8° A 0.044 (1,12) 0.016 (0,40) Seating Plane 0.069 (1,75) MAX 0.010 (0,25) 0.004 (0,10) PINS ** 0.004 (0,10) 8 14 16 A MAX 0.197 (5,00) 0.344 (8,75) 0.394 (10,00) A MIN 0.189 (4,80) 0.337 (8,55) 0.386 (9,80) DIM 4040047/D 10/96 NOTES: A. B. C. D. 16 All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion, not to exceed 0.006 (0,15). Falls within JEDEC MS-012 www.ti.com SLUS458B – AUGUST 2001 MECHANICAL DATA DGK (R-PDSO-G8) PLASTIC SMALL-OUTLINE PACKAGE 0,38 0,25 0,65 8 0,25 M 5 0,15 NOM 3,05 2,95 4,98 4,78 Gage Plane 0,25 1 0°–ā6° 4 3,05 2,95 0,69 0,41 Seating Plane 1,07 MAX 0,15 0,05 0,10 4073329/B 04/98 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion. Falls within JEDEC MO-187 www.ti.com 17 SLUS458B – AUGUST 2001 MECHANICAL DATA P (PDIP) PLASTIC DUAL-IN-LINE 0.400 (10,60) 0.355 (9,02) 8 5 0.260 (6,60) 0.240 (6,10) 1 4 0.070 (1,78) MAX 0.325 (8,26) 0.300 (7,62) 0.020 (0,51) MIN 0.015 (0,38) Gage Plane 0.200 (5,08) MAX Seating Plane 0.010 (0,25) NOM 0.125 (3,18) MIN 0.100 (2,54) 0.021 (0,53) 0.015 (0,38) 0.430 (10,92) MAX 0.010 (0,25) M 4040082/D 05/98 NOTES: A. All linear dimensions are in inches (millimeters). B. This drawing is subject to change without notice. C. Falls within JEDEC MS-001 18 www.ti.com 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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