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UCC28051EVM

UCC28051EVM

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    -

  • 描述:

    EVAL MODULE FOR UCC28051

  • 数据手册
  • 价格&库存
UCC28051EVM 数据手册
Sample & Buy Product Folder Technical Documents Support & Community Tools & Software Reference Design UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 UCC2805x, UCC3805x Transition Mode PFC Controller 1 Features 3 Description • The UCC38050 and UCC38051 are PFC controllers for low-to-medium power applications requiring compliance with IEC 1000-3-2 harmonic reduction standard. The controllers are designed for a boost preregulator operating in transition mode (also referred to as boundary-conduction mode or critical conduction-mode operation). They feature a transconductance voltage amplifier for feedback error processing, a simple multiplier for generating a current command proportional to the input voltage, a current-sense (PWM) comparator, PWM logic, and a totem-pole driver for driving an external FET. 1 • • • • • • • • • Transition Mode PFC Controller for Low Implementation Cost Industry Pin Compatibility With Improved Feature Set Improved Transient Response With Slew-Rate Comparator Zero Power Detect to Prevent Overvoltage Protection (OVP) During Light Load Conditions Accurate Internal VREF for Tight Output Regulation Two UVLO Options OVP, Open-Feedback Protection, and Enable Circuits ±750-mA Peak Gate Drive Current Low Start-Up and Operating Currents Lead (Pb)-Free Packages In the transition mode operation, the PWM circuit is self-oscillating, with the turnon being governed by an inductor zero-current detector (ZCD pin), and the turnoff being governed by the current-sense comparator. Additionally, the controller provides features such as peak current limit, default timer, overvoltage protection (OVP) and enable. Device Information(1) 2 Applications • • • • Single-Stage PFC Flyback Converters for Lighting and Motor Drives Switch-Mode Power Supplies for Desktops, Monitors, TVs, and Set Top Boxes (STBs) AC Adapter Front-End Power Supplies Electronic Ballasts PART NUMBER UCC28050, UCC28051, UCC38050, UCC38051 PACKAGE BODY SIZE (NOM) SOIC (8) 3.91 mm × 4.90 mm PDIP (8) 6.35 mm × 9.81 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Application Diagram UCC38050 1 VO_SNS VCC 2 COMP 3 MULTIN 4 CS 8 DRV 7 GND 6 ZCD 5 UDG−02125 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 4 5 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 10 7.1 Overview ................................................................. 10 7.2 Functional Block Diagram ....................................... 11 7.3 Feature Description................................................. 12 7.4 Device Functional Modes........................................ 14 8 Application and Implementation ........................ 16 8.1 Application Information............................................ 16 8.2 Typical Application ................................................. 16 9 Power Supply Recommendations...................... 21 10 Layout................................................................... 22 10.1 Layout Guidelines ................................................. 22 10.2 Layout Example .................................................... 22 11 Device and Documentation Support ................. 23 11.1 11.2 11.3 11.4 11.5 11.6 Device Support...................................................... Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 23 23 23 23 23 23 12 Mechanical, Packaging, and Orderable Information ........................................................... 24 4 Revision History Changes from Revision F (March 2009) to Revision G • 2 Page Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 5 Pin Configuration and Functions D or P Package 8-Pin SOIC or PDIP Top View VO_SNS 1 8 VCC COMP 2 7 DRV MULTIN 3 6 GND CS 4 5 ZCD Pin Functions PIN NAME COMP CS NO. 2 4 I/O DESCRIPTION O Output of the transconductance error amplifier. Loop compensation components are connected between this pin and ground. The output current capability of this pin is 10-μA under normal conditions, but increases to approximately 1-mA when the differential input is greater than the specified values in the specifications table. This voltage is one of the inputs to the multiplier, with a dynamic input range of 2.5 V to 3.8 V. During zero power or overvoltage conditions, this pin goes below 2.5 V nominal. When it goes below 2.3 V, the zero power comparator is activated, which prevents the gate drive from switching. I This pin senses the instantaneous switch current in the boost switch and uses it as the internal ramp for PWM comparator. The internal circuitry filters out switching noise spikes without requiring external components. In addition, an external R-C filter may be required to suppress the noise spikes. An internal clamp on the multiplier output terminates the switching cycle if this pin voltage exceeds 1.7 V. Additional external filtering may be required. CS threshold is approximately equal to: 2 L= (V AC(min)) ( × V OUT – √2 × VAC(min)) 2 × F s(min) × V OUT × P IN (1) VOFFSET is approximately 75 mV to improve the zero crossing distortion. DRV 7 O The gate drive output for an external boost switch. This output is capable of delivering up to 750mA peak currents during turn-on and turn-off. An external gate drive resistor may be needed to limit the peak current depending on the VCC voltage being used. Below the UVLO threshold, the output is held low. GND 6 – The chip reference ground. All bypassing elements are connected to ground pin with shortest loops feasible. MULTIN 3 I This pin senses the instantaneous boost regulator input voltage through a voltage divider. The voltage acts as one of the inputs to the internal multiplier. Recommended operating range is 0 V to 2.5 V at high line. – The supply voltage for the chip. This pin should be bypassed with a high-frequency capacitor (greater than 0.1-μF) and tied to GND. The UCC38050 has a wide UVLO hysteresis of approximately 6.3 V that allows use of a lower value supply capacitor on this pin for quicker and easier start-up. The UCC38051 has a narrow UVLO hysteresis with of about 2.8 V, and a startup voltage of about 12.5 V for applications where the operation of the PFC device must be controlled by a downstream PWM controller. I This pin senses the boost regulator output voltage through a voltage divider. Internally, this pin is the inverting input to the transconductance amplifier (with a nominal value of 2.5 V) and also is input to the OVP comparator. Additionally, pulling this pin below the ENABLE threshold turns off the output switching, ensuring that the gate drive is held off while the boost output is precharging, and also ensuring no runaway if the feedback path is open. I Input for the zero current detect comparator. The boost inductor current is indirectly sensed through the bias winding on the boost inductor. The ZCD pin input goes low when the inductor current reaches zero and that transition is detected. Internal active voltage clamps are provided to prevent this pin from going below ground or too high. If zero current is not detected within 400 μs, a reset timer sets the latch and gate drive. VCC VO_SNS ZCD 8 1 5 Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 3 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN MAX UNIT 20 V IDD 30 mA ZCD ±10 mA Gate drive current (peak), IDRV DRV ±750 mA Input voltage, VCC VO_SNS, MULTIN, CS 5 V Maximum negative voltage VO_SNS, MULTIN, DRV, CS –0.5 V D package 650 mW Supply voltage, VCC (Internally clamped) Input current into VCC clamp Input current Power dissipation at TA = 50°C 1 W Operating junction temperature range, TJ P package –55 150 °C Storage temperature, Tstg –65 150 °C 300 °C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE UNIT Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 V Charged-device model (CDM), per JEDEC specification JESD22C101 (2) ±500 V SOIC PACKAGE V(ESD) (1) (2) Electrostatic discharge JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN VCC input voltage from a low-impedance source Operating junction temperature, TJ NOM MAX UNIT VCCOFF + 1 V 18 V –40 125 °C 6.4 Thermal Information UCC2805x, UCC3805x THERMAL METRIC (1) D (SOIC) P (PDIP) UNIT 8 PINS 8 PINS RθJA Junction-to-ambient thermal resistance 113.6 55.6 °C/W RθJC(top) Junction-to-case (top) thermal resistance 60.3 45.5 °C/W RθJB Junction-to-board thermal resistance 54.3 32.7 °C/W ψJT Junction-to-top characterization parameter 14 23.1 °C/W ψJB Junction-to-board characterization parameter 53.8 32.6 °C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 6.5 Electrical Characteristics TA = 0°C to 70°C for the UCC3805x, –40°C to +105°C for the UCC2805x, TA = TJ, VCC = 12 V. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 18 19 20 V 75 125 µA SUPPLY VCC operating voltage 18 V Shunt voltage IVCC = 25 mA Supply current, off VCC = VCC turnon threshold –300 mV Supply current, disabled VO_SNS = 0.5 V 2 4 mA Supply current, on 75 kHz, CL = 0 nF 4 6 mA Supply current, dynamic operating 75 kHz, CL = 1 nF 5 7 mA UVLO VCC turnon threshold UCCx8050 15.4 15.8 16.4 UCCx8051 12 12.5 13 VCC turnoff threshold UVLO hysteresis 9.4 9.7 10 UCCx8050 5.8 6.3 6.8 UCCx8051 2.3 2.8 3.3 UCC3805x 2.46 2.5 2.54 UCC2805x 2.45 2.5 2.55 V V V VOLTAGE AMPLIFIER (VO_SNS) Input voltage (VREF) Input bias current VCOMP high VO_SNS = 2.1 V VCOMP low VO_SNS = 2.55 V gM TJ = 25 °C, VCOMP = 3.5 V Source current 4.5 60 V 0.5 µA 5.5 V 1.8 2.45 V 90 130 µS UCCx8050 VO_SNS = 2.1 V, VCOMP = 3.5 V –0.2 –0.1 UCCx8051 VO_SNS = 2.1 V, VCOMP = 2.5 V –200 –300 VO_SNS = 2.7 V, VCOMP = 3.5 V 0.2 1 UCCx8050 VREF + 0.165 VREF + 0.19 VREF + 0.21 UCCx8051 VREF + 0.15 VREF + 0.18 VREF + 0.21 UCCx8050 175 200 225 UCCx8051 150 180 210 UCCx8050 0.62 0.67 0.72 UCCx8051 0.18 0.23 0.28 0.05 0.1 0.2 V 0.87 1/V Sink current mA –400 µA mA OVER VOLTAGE PROTECTION / ENABLE Overvoltage reference Hysteresis Enable threshold Enable hysteresis V mV V MULTIPLIER Multiplier gain constant (k) VMULTIN = 0.5 V, COMP = 3.5 V Dynamic input range, VMULTIN INPUT Dynamic input range, COMP INPUT 0.43 0.65 0 to 2.5 0 to 3.5 2.5 to 3.8 2.5 to 4 Input bias current, MULTIN V V 0.1 1 µA 2.3 2.5 V ZERO POWER Zero power comparator threshold (1) (1) Measured on VCOMP 2.1 Ensured by design. Not production tested. Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 5 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com Electrical Characteristics (continued) TA = 0°C to 70°C for the UCC3805x, –40°C to +105°C for the UCC2805x, TA = TJ, VCC = 12 V. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ZERO CURRENT DETECT Input threshold (rising edge) (1) 1.5 1.7 2 Hysteresis (1) 250 350 450 5 6 0.3 0.65 0.9 200 400 Input high clamp I = 3 mA Input low clamp I = −3 mA Restart time delay V mV V V µs CURRENT SENSE COMPARATOR Input bias current Input offset voltage CS = 0 V (1) 0.1 1 µA 10 mV 300 450 ns 1.7 1.8 V Ω –10 Delay to output CS to DRV Maximum current sense threshold voltage 1.55 PFC GATE DRIVER 6 GT1 pull-up resistance IOUT = –125 mA 5 12 GT1 pull-down resistance IOUT = 125 mA 2 10 Ω GT1 output rise time CLOAD = 1 nF, RLOAD = 10 Ω 25 75 ns GT1 output fall time CLOAD = 1 nF, RLOAD = 10 Ω 10 50 ns Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 6.6 Typical Characteristics 4.0 6 ICC = ON 75 kHZ, 1 nF 5 ICC − Supply Current − mA 3.0 2.5 2.0 UCC38050 1.5 UCC38051 ICC − Supply Current − mA 3.5 1.0 0.5 4 8 12 VCC − Supply Voltage − V 16 2 0 −50 20 Figure 1. Supply Current vs Supply Voltage ICC = ON No Switching −25 0 75 25 50 − Temperature − °C 100 125 Figure 2. Supply Current vs Temperature 20 2.60 UVLO ON (UCCx8050) 18 2.58 16 VREF − Reference Voltage − V VUVLO − UVLO Threshold VOltage − V ICC = ON 75 kHZ, No Load 3 1 0 0 4 UVLO ON (UCCx8051) 14 12 UVLO OFF 10 8 6 UVLO HYSTERESIS (UCCx8050) 4 2.56 2.54 2.52 2.50 2.48 2.46 2.44 2 2.42 UVLO HYSTERESIS (UCCx8051) 0 −50 −25 0 25 50 75 TJ − Temperature − °C 100 2.40 −50 125 100 125 1.800 COMP = 3.5 V 1.4 1.2 COMP = 3.25 V 1.0 0.8 0.6 COMP = 3 V COMP = 2.5 V 0.4 0.2 COMP = 2.75 V 0 0.5 1.0 1.5 2.0 2.5 VMULTIN − Multiplier Input Voltage− V 3.0 Figure 5. Current Sense Input Threshold vs Multiplier Input Voltage Copyright © 2002–2015, Texas Instruments Incorporated VCS(max)− Maximum Current Sense Threshold − V COMP = 3.75 V 1.6 VCS − CS Input Voltage − V 0 25 50 75 TJ − Temperature − °C Figure 4. Reference Voltage vs Temperature Figure 3. UVLO Thresholds vs Temperature 1.8 0.0 −25 1.775 1.750 1.725 1.700 1.675 1.650 1.625 1.600 1.575 1.550 −50 −25 0 25 50 75 TJ − Temperature − °C 100 125 Figure 6. Maximum Current Sense Threshold vs Temperature Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 7 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com Typical Characteristics (continued) 120 400 gM − Transconductance − µS tDELAY − Cureent Sense to Output Delay Time − ns 450 350 300 250 200 150 100 90 80 100 70 50 0 −50 −25 0 25 50 75 TJ − Temperature − °C 100 60 −50 125 Figure 7. CS To Output Delay Time vs Temperature 0 25 50 75 TJ − Temperature − °C 100 125 ICOMP − gM Amplifier Output Current − mA 0.012 1.0 0.5 UCCx8051 0 −0.5 UCCx8050 −1.0 −1.5 2.0 −25 Figure 8. Transconductance vs Temperature 1.5 ICOMP − gM Amplifier Output Current − mA 110 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 0.008 0.004 0 −0.004 −0.008 −0.012 2.40 VVO_SNS − Output Sense Voltage − V Figure 9. gM Amplifier Output Current vs Output Sense Voltage 2.45 2.50 2.55 2.60 VVO_SNS − Output Sense Voltage − V Figure 10. gM Amplifier Output Current vs Output Sense Voltage (Small Signal View) 5.5 2.80 5.0 2.75 VSENSE 4.5 4.0 3.5 3.0 VAO 2.5 2.0 2.70 2.65 OVP ON 2.60 2.55 OVP OFF 2.50 2.45 1.5 25 µs / div Figure 11. Voltage Amplifier Output vs Time (UCC38050) 8 VOVP − OVP Threshold Voltage − V VCOMP − Voltage Amplifier Output − V CLOAD = 10 nF Submit Documentation Feedback 2.40 −50 −25 0 25 50 75 TJ − Temperature − °C 100 125 Figure 12. Overvoltage Protection Thresholds vs Temperature Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 Typical Characteristics (continued) 10 600 8 500 tRESTART − Restart Time − µs IZCD − ZCD Current − mA 6 4 2 0 −2 −4 −6 400 300 200 100 −8 −10 0 0 1 2 3 4 5 6 7 −50 −25 0 VZCD − ZCD Voltage − V 100 125 Figure 14. Restart Time vs Temperature Figure 13. Zero Current Detection Clamp Current vs Voltage 8 2.5 VCC = 12 V VCC = 12 V VOUT(sat) − Output Saturation Voltage − V VOUT(sat) − Output Saturation Voltage − V 25 50 75 TJ − Temperature − °C 7 6 5 4 3 2 1 0 2.0 1.5 1.0 0.5 0 0 100 200 300 400 500 600 700 800 ISOURCE − Source Current − mA Figure 15. Output Saturation Voltage vs Source Current Copyright © 2002–2015, Texas Instruments Incorporated 0 100 200 300 400 500 600 ISINK − Sink Current − mA 700 800 Figure 16. Output Saturation Voltage vs Sink Current Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 9 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 7 Detailed Description 7.1 Overview The UCC38050 and UCC38051 are PFC controllers for low-to-medium power applications requiring compliance with IEC 1000-3-2 harmonic reduction. The controller is designed for a boost preregulator operating in transition mode (also referred to as boundary-conduction mode or critical conduction-mode operation). It features a transconductance voltage amplifier for feedback error processing, a simple multiplier for generating a current command proportional to the input voltage, a current-sense (PWM) comparator, PWM logic, and a totem-pole driver for driving an external FET. The UCC38050 and UCC38051, while being pin-compatible with other industry controllers providing similar functionality, offer many feature enhancements and tighter specifications, leading to an overall reduction in system implementation cost. The system performance is enhanced by incorporation of a zero-power detect function, which allows the controller output to shut down at light load conditions without running into overvoltage. The device also features innovative slew rate enhancement circuits, which improve the large signal transient performance of the voltage error amplifier. The low start-up and operating currents of the device result in low power consumption and ease of start-up. Highly accurate internal bandgap reference leads to tight regulation of output voltage in normal and OVP conditions, resulting in higher system reliability. The enable comparator ensures that the controller is off if the feedback sense path is broken or if the input voltage is very low. There are two key parameteric differences between UCC38050 and UCC38051. The UVLO turn-on threshold of UCC38050 is 15.8 V, while for UCC38051 it is 12.5 V. Secondly, the gM amplifier source current for UCC38050 is typically 1.3 mA, while for UCC38051 it is 300 μA. The higher UVLO turn-on threshold of the UCC38050 allows quicker and easier start-up with a smaller VCC capacitance, while the lower UVLO turn-on threshold of UCC38051 allows the operation of the PFC chip to be easily controlled by the downsteam PWM controller in twostage power converters. The UCC38050 gM amplifier also provides a full 1.3-mA typical source current for faster start-up and improved transient response when output is low, either at start-up or during transient conditions. The UCC38051 scales this source current back down to 300-μA typical source current to gradually increase the error voltage, preventing a step increase in line currents at start-up, but still providing good transient response. The UCC38051 is suitable for multiple applications, including AC adapters, where a two-stage power conversion is needed. The UCC38050 is suitable for applications such as electronic ballasts, where there is no down-stream PWM conversion and the advantages of a smaller VCC capacitor and improved transient response can be realized. 10 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 7.2 Functional Block Diagram 2.7/2.5 V + 0.67/0.57 V 0.23/0.15 V V0_SNS 2.5 V COMP MULTIN ENABLE VREF GOOD REF 8 VCC 7 DRV 6 GND 5 ZCD OVP x x MULT + PWM + 2 ZERO POWER DETECT 3 R Q S Q TIMER + 2.3 V + 40 k: CS UVLO + VREF AND BIAS REG INT. BIAS gm VOL. ERROR AMP 1 VREF OVP + 4 1.7/1.4 V 5 pF Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 11 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 7.3 Feature Description 7.3.1 UVLO and Reference Block This block generates a precision reference voltage used to obtain tightly controlled UVLO threshold. In addition to generating a 2.5-V reference for the non-inverting terminal of the gM amplifier, it generates the reference voltages for blocks such as OVP, enable, zero power, and multiplier. An internal rail of 7.5 V is also generated, to drive all the internal blocks. 7.3.2 Error Amplifier The voltage error amplifier in UCC3805x is a transcoductance amplifier, with a typical transconductance value of 90 μS. A transconductance amplifier is advantageous in that the inverting input of the amplifier is solely determined by the external resistive-divider from the output voltage, and not the transient behavior of the amplifier itself. This allows the VO_SNS pin to be used for sensing overvoltage conditions. The sink and source capability of the error amplifier is approximately 10 μA during normal operation of the amplifier. However, when the VO_SNS pin voltage is beyond the normal operating conditions (VO_SNS > 1.05 × VREF, VO_SNS < 0.88 × VREF), additional circuitry to enhance the slew-rate of the amplifier is activated. Enhanced slew-rate of the compensation capacitor results in a faster start-up and transient response. This prevents the output voltage from drifting too high or too low, which can happen if the compensation capacitor were to be slewed by the normal slewing current of 10 μA. When VO_SNS rises above the normal range, the enhanced sink current capability is in excess of 1 mA. When VO_SNS falls below the normal range, the UCC38050 can source more than 1 mA, and the UCC38051 sources approximately 300 μA. The limited source current in the UCC38051 helps to gradually increase the error voltage on the COMP pin preventing a step increase in line current. The actual rate of increase of VCOMP depends on the compensation network connected to the COMP pin. 7.3.3 Zero Current Detection and Re-Start Timer Blocks When the boost inductor current becomes zero, the voltage at the power MOSFET drain end falls. This is indirectly sensed with a secondary winding connected to the ZCD pin. The internal active clamp circuitry prevents the voltage from going to a negative or a high positive value. The clamp has the sink and source capability of 10 mA. The resistor value in series with the secondary winding should be chosen to limit the ZCD current to less than 10 mA. The rising edge threshold of the ZCD comparator can be as high as 2 V. The auxiliary winding should be chosen such that the positive voltage (when the power MOSFET is off) at the ZCD pin is in excess of 2 V. The restart timer attempts to set the gate drive high in case the gate drive remains off for more than 400 μs nominally. The minimum guaranteed time period of the timer is 200 μs. This translates to a minimum switching frequency of 5 kHz. In other words, the boost inductor value should be chosen for switching frequencies greater than 5 kHz. 12 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 Feature Description (continued) 7.3.4 Enable Block The gate drive signal is held low if the voltage at the VO_SNS pin is less than the ENABLE threshold. This feature can disable the converter by pulling VO_SNS low. If the output feedback path is broken, VO_SNS is pulled to ground, and the output is disabled to protect the power stage. 7.3.5 Zero Power Block When the output of the gM amplifier goes below 2.3 V, the zero power comparator latches the gate drive signal low. The slew rate enhancement circuitry of the gM amplifier activated during overvoltage conditions slews the COMP pin to approximately 2.4 V. This ensures that the zero power comparator is not activated during transient behavior, when the slew rate enhancement circuitry is enhanced. 7.3.6 Multiplier Block The multiplier block has two inputs. One is the error amplifier output voltage (VCOMP), and the other is VMULTIN, which is obtained by a resistive divider from the rectified line. The multiplier output is approximately 0.67 × VMULTIN × (VCOMP − 2.5 V). There is a positive offset of about 75 mV to the VMULTIN signal because this improves the zero-crossing distortion and thus the THD performance of the controller in the application. The dynamic range of the inputs can be found in Electrical Characteristics. 7.3.7 Overvoltage Protection (OVP) Block The OVP feature in the part is not activated under most operating conditions because of the presence of the slew rate enhancement circuitry present in the error amplifier. As soon as the output voltage reaches to approximately 5% to 7% above the nominal value, the slew rate enhancement circuit is activated, and the error amplifier output voltage is pulled below the dynamic range of the multiplier block. This prevents further rise in output voltage. If the COMP pin is not pulled low fast enough and the voltage rises further, the OVP circuit acts as a second line of protection. When the voltage at the VO_SNS pin is more than 7.5% of the nominal value (> (VREF + 0.19)), the OVP feature is activated. It stops the gate drive from switching as long as the voltage at the VO_SNS pin is above the nominal value (VREF). This prevents the output DC voltage from going above 7.5% of the nominal value designed for, and protects the switch and other components of the system such as the boost capacitor. Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 13 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 7.4 Device Functional Modes 7.4.1 Transition Mode Control The boost converter, the most common topology used for power factor correction, can operate in two modes: continuous conduction code (CCM) and discontinuous conduction mode (DCM). Transition mode control, also referred to as critical conduction mode (CRM) or boundary conduction mode, maintains the converter at the boundary between CCM and DCM by adjusting the switching frequency. The CRM converter typically uses a variation of hysteretic control, with the lower boundary equal to zero current. It is a variable frequency control technique that has inherently stable input current control while eliminating reverse recovery rectifier losses. As shown in Figure 17, the switch current is compared to the reference signal (output of the multiplier) directly. This control method has the advantage of simple implementation and good power factor correction. L VAC D Q C Load RIAC IAC ZCD X ÷ MULT X IMO + S R Q Gate Driver Logic VEA + VREF UDG−02124 Figure 17. Basic Block Diagram of CRM Boost PFC The power stage equations and the transfer functions of the CRM are the same as the CCM. However, implementations of the control functions are different. Transition mode forces the inductor current to operate just at the border of CCM and DCM. The current profile is also different, and affects the component power loss and filtering requirements. The peak current in the CRM boost is twice the amplitude of CCM, leading to higher conduction losses. The peak-to-peak ripple is twice the average current, which affects MOSFET switching losses and magnetics ac losses. 14 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 Device Functional Modes (continued) IAVERAGE (a) CCM IPEAK IAVERAGE (b) DCM IPEAK IAVERAGE Note: Operating Frequency >> 120 Hz (C) CRM UDG−02123 Figure 18. PFC Inductor Current Profiles For low to medium power applications up to approximately 300 W, the CRM boost has an advantage in losses. The filtering requirement is not severe, and therefore is not a disadvantage. For medium to higher power applications, where the input filter requirements dominate the size of the magnetics, the CCM boost is a good choice due to lower peak currents (which reduces conduction losses) and lower ripple current (which reduces filter requirements). The main tradeoff in using CRM boost is lower losses due to no reverse recovery in the boost diode vs. higher ripple and peak currents. Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 15 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The UCC38050 and UCC38051 are switch-mode controllers used in boost converters for power factor correction operating in transition mode. In the transition mode operation, the PWM circuit is self-oscillating, with the turnon being governed by an inductor zero-current detector (ZCD pin), and the turnoff being governed by the currentsense comparator. Additionally, the controller provides features such as peak current limit, default timer, OVP, and enable. There are two key parametric differences between UCC38050 and UCC38051. The UVLO turnon threshold of UCC38050 is 15.8 V, while for UCC38051 it is 12.5 V. Secondly, the gM amplifier source current for UCC38050 is typically 1.3 mA, while for UCC38051 it is 300 μA. The UCC38051 is suitable for multiple applications, including AC adapters, where a two-stage power conversion is needed. The UCC38050 is suitable for applications such as electronic ballasts, where there is no down-stream PWM conversion and the advantages of a smaller VCC capacitor and improved transient response can be realized. Figure 19 is an example of a critical conduction mode power factor correction boost converter utilizing the UCC38050. 8.2 Typical Application The UCC38050 is used for the off-line power factor corrected pre-regulator with operation over a universal input range of 85 V to 265 V with a 400-VDC regulated output. The schematic is shown in Figure 19, and the board layout for the reference design is shown in Figure 24. + + + Figure 19. Universal Line Input 100-W Boost Converter 16 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 Typical Application (continued) RUP − RAC1 + RG1 L COUT RB RZC RS1 RO1 2.7/2.5 V V REF OVP + INT. BIAS CB UVLO VREF AND BIAS REG + VCC VO_SNS ENABLE + 0.67/0.57 V (50) 0.23/0.15 V (51) REF V REF GOOD gM E/A 8 OVP 1 2.5 V RO2 x ÷ MULT x + COMP 7 PWM + R Q S Q DRV 2 MULTIN CV1 ZERO POWER DETECT 3 CV2 RV1 RAC2 RV1 2.3 V CS GND 6 TIMER + + 40 k Ω 1.7 V/1.4 V ZCD 4 CAC1 5 5 pF CS1 UDG−02008 Figure 20. Typical Application Diagram 8.2.1 Design Requirements Table 1 shows the design requirements for a CCM, PFC boost converter utilizing the UCC38050. Table 1. UCC38050 Design Requirements PARAMETER VIN TEST CONDITION Input voltage MIN TYP 85 Input frequency MAX UNIT 265 VRMS 60 Hz VOUT Output voltage DC VIN = 85 VRMS 370 400 425 V VOUT Output voltage DC VIN = 265 VRMS 370 390 410 V POUT Output power 100 W 0 Output voltage ripple VIN = 85 VRMS Efficiency POUT = 100 W Total harmonic distortion (THD) VIN = 85 VRMS, POUT = 100 W 5% Total harmonic distortion (THD) VIN = 265 VRMS, POUT = 100 W 15% Hold-up time 3% 90% 16.7 Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 ms 17 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 8.2.2 Detailed Design Procedure For a selected VOUT and minimum switching frequency, the following equations outline the design guidelines for power stage component selection, using a universal input, 100-W PFC converter with an output voltage of 390 V. Refer to Figure 20 for reference designators. 8.2.2.1 Inductor Selection In the transition mode control, the inductor value must be calculated to start the next switching cycle at zero current. The time it takes to reach zero depends on line voltage and inductance and as shown in Equation 2. L determines the frequency range of the converter. 2 L= (V AC(min)) ( ) √ × V OUT – 2 × V AC(min) 2 × F s(min) × V OUT × P IN where • • • VAC = RMS line voltage VAC(min) = minimum AC line voltage PIN = maximum input power averaged over the ac line period IL(peak) = 2 × √2 × (PIN/VAC(min)) IL(rms) = IL(peak) / √6 (2) (3) (4) 8.2.2.2 MOSFET Selection The main switch selection is driven by the amount of power dissipation allowable. Choose a device that minimizes gate charge and capacitance, and minimizes the sum of switching and conduction losses at a given frequency. I Q(rms_crm) = √ 1 – (4 × 2 ) × √ 6 V ) × ILPEAK(crm) ( 9 πAC(min) × V OUT (5) (6) VQ(max) = VOUT 8.2.2.3 Diode Selection The effects of the reverse recovery current in the diode can be eliminated with relatively little negative impact to the system. The diode selection is based on reverse voltage, forward current, and switching speed. ID(avg) = IOUT(avg) (7) I D(rms) = I L(peak) √ √2 × VAC π × V OUT (8) (9) VD(peak) = VOUT 8.2.2.4 Capacitor Selection The hold-up time is the main requirement in determining the output capacitance. ESR and the maximum RMS ripple current rating can also be important, especially at higher power levels. COUT(min) = (2 × POUT × tHOLDUP) / ((VOUT)2 – (VOUT(min))2) where • VOUT(min) = minimum regulator input voltage for operation I C(rms) = 18 √( 2 ) I L(peak) × √2 × VAC(max) Submit Documentation Feedback π × V OUT – ( P OUT V OUT (10) 2 ) + (ac rms load currents) 2 (11) Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 8.2.2.5 Multiplier Set-Up Select RAC1 and RAC2 so that their ratio uses the full dynamic range of the multiplier input at the peak line voltage, and yet with values small enough to negate the effects of the multiplier bias current. To use the maximum range of the multiplier, select the divider ratio so that VMULTIN, evaluated at the peak of the maximum ac line voltage, is the maximum of the minimum dynamic input range of MULTIN, which is 2.5 V. Choose RAC1 so that it has at least 100 μA at the peak of the minimum AC operating line voltage. R AC1 √2 V – 1 = 2.5 AC(max) R AC2 (12) ) ( In extreme cases, switching transients can contaminate the MULTIN signal, so it can be beneficial to add capacitor CAC1. Select the value of CAC1 so that the corner frequency of the resulting filter is greater than the lowest switching frequency. The low corner frequency of this filter may compromise the overall power factor. 8.2.2.6 Sense Resistor Selection The current sense resistor value must be chosen to limit the output power, and it must also use the full dynamic range of the multiplier during normal steady state operation. The value of RS1 is thus selected for maximum power operation at low ac line voltage conditions. To use the full dynamic range, set the VSENSE threshold as a function of the dynamic input range of VCOMP and the peak of the minimum MULTIN voltage. R S1 = 0.67 × (COMP(MAX) – COMP (MIN)) × (MULTIN (PEAK)@VAC(min) – 0.075) 2 × √2 × P IN(max) V AC(min) where • • • COMP(MAX) = 3.8 V COMP(MIN) = 2.5 V MULTIN(PEAK)@VAC(min) = √2 × VAC(min)( RAC2 / (RAC2+RAC1) ) (13) If the exact value RS1 is not available, RS2 and RS3 can be added for further scaling. The CS pin already has an internal filter for noise due to switching transients. Additional filtering at switching transient frequencies can be achieved by adding CS1. 8.2.2.7 Output Voltage Sense Design Select the divider ratio of RO1 and RO2 to set the VO_SNS voltage to 2.5 V at the desired output voltage. The current through the divider should be at least 200 μA. 8.2.2.8 Voltage Loop Design How well the voltage control loop is designed directly impacts line current distortion. UCC38050 employs a transconductance amplifier (gM amp) with gain scheduling for improved transient response (refer to Figure 9). Integral type control at low frequencies is preferred, because the loop gain varies considerably with line conditions. The largest gain occurs at maximum line voltage. If the power factor corrector load is dc-to-dc switching converter, the small signal model of the controller and the power factor corrector, from COMP to PFC output voltage is given by: 2 ^ V OUT(s) ^ V COMP(s) = V OUT(avg) k 1 × (V AC) × 1 × R S1 × k CRM × C OUT S where • • • • ^VOUT = small signal variations in VOUT ^VCOMP = small signal variations in VCOMP k1 = multiplier gain = 0.65 kCRM = peak to average factor = 2 Copyright © 2002–2015, Texas Instruments Incorporated (14) Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 19 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com A controller that has integral control at low frequencies requires a zero near the crossover frequency to be stable. The resulting gM amplifier configuration is shown in Figure 21. VOUT + CV1 CV2 V REF RV1 Figure 21. gM Amplifier Configuration The compensator transfer function is: 1 R V1 u C V1 u s gM AV u C V1 C V2 § § ªC u C V2 ¼º · · s ¨ 1 ¨ R V1 u ¬ V1 ¸ u s¸ ¨ ¨ C V1 u C V2 º¼ ¸¹ ¸ ª ¬ © © ¹ where • gM = DC transconductance gain = 100 μs (15) The limiting factor of the gain is usually the allowable third harmonic distortion, although other harmonics can dominate. The crossover frequency of the control loop will be much lower than twice the AC line voltage. To choose the compensator dynamics, determine the maximum allowable loop gain at twice the line frequency, and solve for capacitor CV2. This also determines the crossover frequency. § · § VAC(max) · gM u k1 ¸ C V2 ¨ ¸2u¨ ¨ VOUT(avg) u RS1 u k(crm) u COUT(max loop gainat 2f ) ¸ © 4SfAC ¹ AC ¹ © (16) fCO VAC S gM u k1 C V2 u VOUT u RS1 u k(cmr) u COUT (17) Select CV1 so that the low frequency zero is one-tenth of the crossover frequency. CV1 = 9 CV2 (18) Select RV1 so that the pole is at the crossover frequency. ≈ 1 / 2π fCO CV2 20 (19) Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 8.2.3 Application Curves Figure 22 and Figure 23 show the input current and rectified line for the power module. • Channel 3 = Rectified Line Voltage • Channel 4 = Power Module Input Current VIN = 85 V POUT = 100 W Figure 22. Rectified Line Voltage and Power Module Input Current at 85 V/100 W VIN = 265 V POUT = 100 W Figure 23. Rectified Line Voltage and Power Module Input Current at 265 V/100 W 9 Power Supply Recommendations The supply voltage for the device comes from VCC pin. This pin must be bypassed with a high-frequency capacitor (greater than 0.1 μF) and tied to GND. The UCC38050 has a wide UVLO hysteresis of approximately 6.3 V that allows use of a lower value supply capacitor on this pin for quicker and easier start-up. The UCC38051 has a narrow UVLO hysteresis with of about 2.8 V, and a start-up voltage of about 12.5 V for applications where the operation of the PFC device must be controlled by a downstream PWM controller. Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 21 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 10 Layout 10.1 Layout Guidelines 10.1.1 Bias Current The bias voltage is supplied by a bias winding on the inductor. Select the turns ratio so that sufficient bias voltage can be achieved at low AC line voltage. The bias capacitor must be large enough to maintain sufficient voltage with AC line variations. Connect a 0.1-μF bypass capacitor between the VCC pin and the GND pin as close to the integrated circuit as possible. For wide line variations, a resistor, RB, is necessary to permit clamping action. The bias voltage should also be clamped with an external zener diode to a maximum of 18 V. 10.1.2 Zero Current Detection The zero current detection activates when the ZCD voltage falls below 1.4 V. The bias winding can provide the necessary voltage. This pin has a clamp at approximately 5 V. Add a current limiting resistor, RZC, to keep the maximum current below 1 mA. 10.2 Layout Example Figure 24. UCC38050 Layout Example Figure 25. UCC38050 Bottom-Layer Layout Example 22 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 UCC28050, UCC28051, UCC38050, UCC38051 www.ti.com SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 11 Device and Documentation Support 11.1 Device Support 11.1.1 Development Support Reference Design, 100-W Universal Line Input PFC Boost Converter Using the UCC38050 (SLUU134) 11.2 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 2. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY UCC28050 Click here Click here Click here Click here Click here UCC28051 Click here Click here Click here Click here Click here UCC38050 Click here Click here Click here Click here Click here UCC38051 Click here Click here Click here Click here Click here 11.3 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.5 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.6 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. Copyright © 2002–2015, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 23 UCC28050, UCC28051, UCC38050, UCC38051 SLUS515G – SEPTEMBER 2002 – REVISED DECEMBER 2015 www.ti.com 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 24 Submit Documentation Feedback Copyright © 2002–2015, Texas Instruments Incorporated Product Folder Links: UCC28050 UCC28051 UCC38050 UCC38051 PACKAGE OPTION ADDENDUM www.ti.com 20-May-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) UCC28050D ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28050 Samples UCC28050DR ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28050 Samples UCC28050P ACTIVE PDIP P 8 50 RoHS & Green NIPDAU N / A for Pkg Type -40 to 105 28050 Samples UCC28051D ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28051 Samples UCC28051DG4 ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28051 Samples UCC28051DR ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28051 Samples UCC28051DRG4 ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 105 28051 Samples UCC28051P ACTIVE PDIP P 8 50 RoHS & Green NIPDAU N / A for Pkg Type -40 to 105 28051 Samples UCC38050D ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-1-260C-UNLIM 0 to 70 38050 Samples UCC38050DR ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM 0 to 70 38050 Samples UCC38050P ACTIVE PDIP P 8 50 RoHS & Green NIPDAU N / A for Pkg Type 0 to 70 38050 Samples UCC38051D ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-1-260C-UNLIM 0 to 70 38051 Samples (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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