UC2901-EP www.ti.com SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 ISOLATED FEEDBACK GENERATOR Check for Samples: UC2901-EP FEATURES 1 • • • • • • • • Controlled Baseline – One Assembly/Test Site, One Fabrication Site Extended Temperature Performance of –55°C to 125°C Enhanced Diminishing Manufacturing Sources (DMS) Support Enhanced Product-Change Notification Qualification Pedigree (1) Amplitude-Modulation System for Transformer Coupling an Isolated Feedback Error Signal Low-Cost Alternative to Optical Couplers Internal 1% Reference and Error Amplifier • • • Internal Carrier Oscillator Usable to 5 MHz Modulator Synchronizable to an External Clock Loop Status Monitor D PACKAGE (TOP VIEW) +VIN CT STATUS EXTCLK COMP N/C DRIVERB INV DRIVERA NI VREF N/C (1) Component qualification in accordance with JEDEC and industry standards to ensure reliable operation over an extended temperature range. This includes, but is not limited to, Highly Accelerated Stress Test (HAST) or biased 85/85, temperature cycle, autoclave or unbiased HAST, electromigration, bond intermetallic life, and mold compound life. Such qualification testing should not be viewed as justifying use of this component beyond specified performance and environmental limits. RT GND N/C = No internal connection XXX DESCRIPTION The UC2901 is designed to solve many of the problems associated with closing a feedback control loop across a voltage isolation boundary. As a stable and reliable alternative to an optical coupler, UC2901 features an amplitude modulation system that allows a loop error signal to be coupled with a small RF transformer or capacitor. The programmable, high-frequency oscillator within the UC2901 permits the use of smaller, less-expensive transformers, which can readily be built to meet the isolation requirements of today's line-operated power systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a system clock or to the switching frequency of an SMPS. An additional feature is a status monitoring circuit that provides an active low output when the sensed error voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are disabled until the input supply has reached a sufficient level to allow proper operation of the device. Because these devices also can be used as a DC driver for optical couplers, the benefits of 4.5 V to 40 V supply operation, a 1% accurate reference, and a high-gain general-purpose amplifier offer advantages, even though an AC system may not be desired. ORDERING INFORMATION TA –55°C to 125°C (1) PACKAGE (1) D (SOIC) ORDERABLE PART NUMBER TOP-SIDE MARKING UC2901MDREP UC2901MEP Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at www.ti.com/sc/package. 1 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. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2006–2010, Texas Instruments Incorporated UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 www.ti.com UC2901 SIMPLIFIED SCHEMATIC VIN 150 mV STATUS VIN 4K STATUS AMPLIFIERS 4K DRIVERB NI 150 mV DRIVERA 700 mA 700 mA INV MODULATOR VIN VIN ERROR AMPLIFIER X1 2K CT OSCILLATOR VIN 1K 3K COMP 150 mA 5K EXTCLK 10 K BIAS VREF BIAS 500 X2 BIAS 1.5-VOLT REFERENCE 1.25 V 2.5 K RT GND Absolute Maximum Ratings (1) over operating free-air temperature range (unless otherwise noted) MIN VIN Input supply voltage 40 V –10 mA Driver output current –35 mA Status indicator voltage 40 V Status indicator current 20 mA External clock input 40 V –0.5 Power dissipation at TA = 25°C 35 V 1000 mW Operating junction temperature range –55 150 °C Storage temperature range (2) –65 150 °C 300 °C Lead temperature (soldering, 10 seconds) 2 UNIT Reference output current Error amplifier inputs (1) (2) MAX Voltages are referenced to ground, pin 7. Currents are positive into, and negative out of the specified terminal. Long-term high-temperature storage and/or extended use at maximum recommended operating conditions may result in a reduction of overall device life. See http://www.ti.com/ep_quality for additional information on enhanced plastic packaging. Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated Product Folder Link(s): UC2901-EP UC2901-EP www.ti.com SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 DISSIPATION RATING TABLE - FREE-AIR TEMPERATURE PACKAGE AIR FLOW (CFM) TA≤25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA= 70°C POWER RATING TA= 85°C POWER RATING TA=125°C POWER RATING D 0 1000 mW 8 mW/°C 630 mW 510 mW 180 mW Electrical Characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT TA = 25°C 1.485 1.5 1.515 TMIN ≤ TA ≤ TMAX 1.470 1.5 1.530 2 10 mV Reference Section Output voltage Line regulation VIN = 4.5 to 35 V Load regulation IOUT = 0 to 5 mA Short-circuit current TA = 25°C V 4 10 mV –35 –55 mA 1 4 mV Error Amplifier Section (To Compensation Terminal) Input offset voltage VCM = 1.5 V Input bias current VCM = 1.5 V –1 –3 mA Input offset current VCM = 1.5 V 0.1 1 mA Small-signal open-loop gain 40 60 dB CMRR VCM = 0.5 V to 7.5 V 60 80 dB PSRR VIN = 5 V to 25 V 80 100 dB Output swing, ΔVO 0.4 0.7 V Maximum sink current 90 150 mA Maximum source current –2 –3 mA 1 MHz 0.3 V/ms Gain bandwidth product Slew rate Modulators/Drivers Section (From Compensation Terminal) Voltage gain 11 12 Output swing ±1.6 ±2.8 Driver sink current 500 700 mA Driver source current –15 –35 mA 25 MHz Gain bandwidth product 13 dB V Oscillator Section Initial accuracy TA = 25°C 140 TMIN ≤ TA ≤ TMAX 130 Line sensitivity VIN = 5 V to 35 V Maximum frequency RT = 10 K, CT = 10 pF External clock low threshold Pin 1 (CT) = VIN External clock high threshold Pin 1 (CT) = VIN 150 0.15 160 kHz 170 kHz 0.35 %/V 5 MHz 0.5 V 1.6 V Status Indicator Section Input voltage window At E/A inputs, VCM = 1.5 V Saturation voltage E/A Δinput = 0 V, ISINK = 1.6 mA Maximum output current Pin 13 = 3 V, E/A Δ input = 0 V Leakage current Pin 13 = 40 V, E/A Δ input = 0.2 V Supply current VIN = 35 V ±135 8 ±150 ±165 mV 0.45 V 15 mA 0.05 1 mA 5 8 mA UVLO Section Drivers-enabled threshold At input supply VIN 3.9 4.5 Status output-enabled threshold At input supply VIN 3.9 4.5 V Change in reference output When VIN reaches UVLO threshold –2 –30 mV Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated Product Folder Link(s): UC2901-EP V 3 UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 www.ti.com 10 V VIN = 10 V OSC f = 1 Mhz TJ = 25°C Open-Loop Voltage Gain Decibels 80 0.1 mF INPUT 0.22 mF DC BIAS 60 GAIN 50 40 0 PHASE 30 45 20 90 10 135 0 180 10 10 k 100 10 k 100 k 1k Frequency - Hertz 1M 1N914 1:1 1 mH 70 Phase - Degrees 100 pF 270 pF OUTPUT 10 k 1 mH (SEE NOTE) Note: Transformer Data: N1 = N2 = 20 TAWG 26 Core = Ferroxcube 3E2A Ferrite, 0.5” O.D. Toroid Carrier Frequency = 1 Mhz Figure 1. Transformer-Coupled Open-Loop Transfer Function Oscillator Frequency 10 10 10 10 8 Peak Differential Driver Output Swing - V 10 fosc = 1.27 R TC T 7 6 VIN = 10 V RT = 10 kW TJ = 25°C 5 4 2.8 2.6 2.4 2.2 2.0 1.8 1.6 -55 -35 -15 5 25 45 65 85 105 125 Temperature - °C 3 10 5 10 3.4 3.2 3.0 10 4 10 3 10 2 10 1 Figure 3. Typical Driver Output Swing vs Temperature CT Value - Picofarads Figure 2. Oscillator Frequency 4 Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated Product Folder Link(s): UC2901-EP UC2901-EP www.ti.com SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 APPLICATION INFORMATION The error amplifier compensation terminal, pin 12, is intended as a source of feedback to the amplifier's inverting input at pin 11. For most applications, a series DC blocking capacitor should be part of the feedback network. The amplifier is compensated internally for unity feedback. The waveform at the driver outputs is a squarewave, with an amplitude that is proportional to the error amplifier input signal. There is a fixed 12 dB of gain from the error amplifier compensation pin to the modulator driver outputs. The frequency of the output waveform is controlled by either the internal oscillator or an external clock signal. With the internal oscillator, the squarewave has a fixed 50% duty cycle. If the internal oscillator is disabled by connecting pin 1, CR, to VIN, then the frequency and duty cycle of the output is determined by the input clock waveform at pin 2. If the oscillator remains disabled, and there is not clock input at pin 2, there will be a linear 12-dB signal gain to one or the other of the driver outputs, depending on the DC state of pin 2. The driver outputs are emitter followers that source a minimum of 15 mA of current. The sink current, internally limited at 700 mA, can be increased by adding resistors to ground at the driver outputs. Primary Power and Switches Supply Output Power Transformer UC2901 To Supply Monitor STATUS VIN -/+ 10% +/- COMP DRIVERB To PWM Controller E/A + X4 RF Coupling Transformer DRIVERA NI VIN 1.5 V Reference Oscillator EXTCLK CT INV RT VREF GND Figure 4. Transformer-Coupled Feedback Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated Product Folder Link(s): UC2901-EP 5 UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 Primary Power and Switches www.ti.com Supply Output Power Transformer U2901 To Supply Monitor STATUS VIN -/+ 10% +/- COMP DRIVERB To PWM Controller X4 RF Coupling Transformer INV E/A + DRIVERA NI VIN 1.5 V Reference Oscillator EXTCLK CT VREF RT GND Figure 5. Feedback-Coupled at Switching Frequency POWER TRANSFORMER SUPPLY CURRENT PRIMARY POWER AND SWITCHES TO SUPPLY MONITOR STATUS UC2901 -/+ VIN 10% +/- COMP OPTICAL COUPLER DRIVERB TO PWM CONTROLLER INV X4 DRIVERA VIN E/A + 1.5 V REFERENCE EXTCLK OSCILLATOR CT NI VREF GND RT Figure 6. Optically-Coupled DC Feedback 6 Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated Product Folder Link(s): UC2901-EP PACKAGE OPTION ADDENDUM www.ti.com 10-Mar-2010 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty UC2901MDREP ACTIVE SOIC D 14 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UC2901MDREPG4 ACTIVE SOIC D 14 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM V62/07609-01XE ACTIVE SOIC D 14 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM Lead/Ball Finish MSL Peak Temp (3) (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. 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