UC1524 UC2524 UC3524 Advanced Regulating Pulse Width Modulators FEATURES DESCRIPTION • Complete PWM Power Control Circuitry The UC1524, UC2524 and UC3524 incorporate on a single monolithic chip all the functions required for the construction of regulating power supplies, inverters or switching regulators. They can also be used as the control element for high-power-output applications. The UC1524 family was designed for switching regulators of either polarity, transformer-coupled dc-to-dc converters, transformerless voltage doublers and polarity converter applications employing fixed-frequency, pulse-width modulation techniques. The dual alternating outputs allow either single-ended or push-pull applications. Each device includes an on-chip reference, error amplifier, programmable oscillator, pulse-steering flip-flop, two uncommitted output transistors, a high-gain comparator, and current-limiting and shut-down circuitry. The UC1524 is characterized for operation over the full military temperature range of -55°C to +125°C. The UC2524 and UC3524 are designed for operation from -25°C to +85°C and 0° to +70°C, respectively. • Uncommitted Outputs for Single-ended or Push-pull Applications • Low Standby Current…8mA Typical • Interchangeable with SG1524, SG2524 and SG3524, Respectively BLOCK DIAGRAM VIN 15 VREF OSC OUT 16 3 +5V TO ALL INTERNAL CIRCUITRY REFERENCE REGULATOR +5V 12 CA 11 EA 13 CB 14 EB 5 –SENSE 4 +SENSE Q RT 6 CT 7 OSC R Q (RAMP) INV INPUT 1 NI INPUT 2 GROUND (SUBSTRATE) +5V +5V COMPARATOR EA 8 1k 10k CL 10 9 SHUTDOWN COMPENSATION SLUS180D - NOVEMBER 1999 - REVISED AUGUST 2002 UC1524 UC2524 UC3524 CONNECTION DIAGRAM ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage, VCC (Notes 2 and 3) . . . . . . . . . . . . . . . . . 40V Collector Output Current. . . . . . . . . . . . . . . . . . . . . . . . . 100mA Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 50mA Current Through CT Terminal . . . . . . . . . . . . . . . . . . . . . . –5mA Power Dissipation at TA = +25°C (Note 4). . . . . . . . . . 1000mW Power Dissipation at TC = +25°C (Note 4). . . . . . . . . . 2000mW Operating Junction Temperature Range . . . . –55°C to +150°C Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C INV INPUT 1 EA Note 1: Over operating free-air temperature range unless otherwise noted. Note 2: All voltage values are with respect to the ground terminal, pin 8. Note 3: The reference regulator may be bypassed for operation from a fixed 5V supply by connecting the VCC and reference output pins both to the supply voltage. In this configuration the maximum supply voltage is 6V. Note 4: Consult packaging section of databook for thermal limitations and considerations of package. NON INV INPUT 2 OSC OUT 3 CLSENSE(+) 4 REF REG CL CLSENSE (–-) RT 5 6 OSC CT 7 GND 8 S/D 16 VREF 15 VIN 14 EB 13 CB 12 CA 11 EA 10 S/D 9 COMP RECOMMENDED OPERATING CONDITIONS Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . 8V to 40V Reference Output Current . . . . . . . . . . . . . . . . . . . . . 0 to 20mA Current through CT Terminal . . . . . . . . . . . . . –0.03mA to –2mA Timing Resistor, RT . . . . . . . . . . . . . . . . . . . . . 1.8kΩ to 100kΩ Timing Capacitor, CT . . . . . . . . . . . . . . . . . . . 0.001µF to 0.1µF Operating Ambient Temperature Range UC1524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C UC2524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –25°C to +85°C UC3524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for T A = –55°C to +125°C for the UC1524, –25°C to +85°C for the UC2524, and 0°C to +70°C for the UC3524, V IN = 20V, and f = 20kHz, T A = T J. UC1524/UC2524 UC3524 UNITS PARAMETER TEST CONDITIONS MIN MAX MIN MAX Reference Section Output Voltage 4.8 5.0 5.2 4.6 5.0 5.4 V 10 20 10 30 mV Line Regulation VIN = 8 to 40V 20 50 20 50 mV Load Regulation IL = 0 to 20mA 66 66 dB Ripple Rejection f = 120Hz, TJ = 25°C 100 100 mA Short Circuit Current Limit VREF = 0, TJ = 25°C Temperature Stability Over Operating Temperature Range 0.3 1 0.3 1 % 20 20 mV Long Term Stability TJ = 125°C, t = 1000 Hrs. Oscillator Section 300 300 kHz Maximum Frequency CT = .001mfd, RT = 2kΩ 5 5 % Initial Accuracy RT and CT Constant 1 1 % Voltage Stability VIN = 8 to 40V, TJ = 25°C Temperature Stability Over Operating Temperature Range 5 5 % 3.5 3.5 V Output Amplitude Pin 3, TJ = 25°C 0.5 0.5 Output Pulse Width CT = .01mfd, TJ = 25°C µs Error Amplifier Section 0.5 5 2 10 mV Input Offset Voltage VCM = 2.5V 2 10 2 10 Input Bias Current VCM = 2.5V µA Open Loop Voltage Gain 72 80 60 80 dB 1.8 3.4 1.8 3.4 V Common Mode Voltage TJ = 25°C 2 UC1524 UC2524 UC3524 ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for T A = –55°C to +125°C for the UC1524, –25°C to +85°C for the UC2524, and 0°C to +70°C for the UC3524, V IN = 20V, and f = 20kHz, T A = T J. UC1524/UC2524 UC3524 UNITS PARAMETER TEST CONDITIONS MIN MAX MIN MAX Error Amplifier Section (cont.) 70 70 dB Common Mode Rejection Ratio TJ = 25°C 3 3 MHz Small Signal Bandwidth AV = 0dB, TJ = 25°C 0.5 3.8 0.5 3.8 V Output Voltage TJ = 25°C Comparator Section Duty-Cycle % Each Output On 0 45 0 45 % Input Threshold Zero Duty-Cycle 1 1 V Maximum Duty-Cycle 3.5 3.5 V Input Bias Current 1 1 µA Current Limiting Section 190 200 210 180 200 220 mV Sense Voltage Pin 9 = 2V with Error Amplifier Set for Maximum Out, TJ = 25°C Sense Voltage T.C. 0.2 0.2 mV/°C –1 +1 –1 +1 V Common Mode Voltage TJ = –55°C to 85°C for the –1V to 1V Limit –0.3 +1 V TJ = 125°C Output Section (Each Output) Collector-Emitter Voltage 40 40 V 0.1 50 0.1 50 Collector Leakage Current VCE = 40V µA 1 2 1 2 V Saturation Voltage IC = 50mA 17 18 17 18 V Emitter Output Voltage VIN = 20V 0.2 0.2 Rise Time RC = 2kΩ, TJ = 25°C µs Fall Time RC = 2kΩ, TJ = 25°C 0.1 0.1 µs VIN = 40V 8 10 8 10 mA Total Standby Current (Note) PRINCIPLES OF OPERATION The UC1524 is a fixed-frequency pulse-width-modulation voltage regulator control circuit. The regulator operates at a frequency that is programmed by one timing resistor (RT), and one timing capacitor (CT), RT establishes a constant charging current for CT. This results in a linear voltage ramp at CT, which is fed to the comparator providing linear control of the output pulse width by the error amplifier. The UC1524 contains an on-board 5V regulator that serves as a reference as well as powering the UC1524’s internal control circuitry and is also useful in supplying external support functions. This reference voltage is lowered externally by a resistor divider to provide a reference within the common-mode range of the error amplifier or an external reference may be used. The power supply output is sensed by a second resistor divider network to generate a feedback signal to the error amplifier. The amplifier output voltage is then compared to the linear voltage ramp at CT. The resulting modulated pulse out of the high-gain comparator is then steered to the appropriate output pass transistor (Q1 or Q2) by the pulse-steering flip-flop, which is synchronously toggled by the oscillator output. The oscillator output pulse also serves as a blanking pulse to assure both outputs are never on simultaneously during the transition times. The width of the blanking pulse is controlled by the valve of CT. The outputs may be applied in a push-pull configuration in which their frequency is half that of the base oscillator, or paralleled for single-ended applications in which the frequency is equal to that of the oscillator. The output of the error amplifier shares a common input to the comparator with the current limiting and shutdown circuitry and can be overridden by signals from either of these inputs. This common point is also available externally and may be employed to control the gain of, or to compensate, the error amplifier or to provide additional control to the regulator. 3 UC1524 UC2524 UC3524 TYPICAL CHARACTERISTICS Open-loop voltage amplification of error amplifier vs frequency. Oscillator frequency vs timing components. Output dead time vs timing capacitance value. Output saturation voltage vs load current. 4 UC1524 UC2524 UC3524 APPLICATION INFORMATION amplifier. This can easily be done with the circuit in Figure 1: Oscillator The oscillator controls the frequency of the UC1524 and is programmed by RT and CT according to the approximate formula: 1.18 f′ RT CT where where where Synchronous Operation When an external clock is desired, a clock pulse of approximately 3V can be applied directly to the oscillator output terminal. The impedance to ground at this point is approximately 2kΩ. In this configuration RT CT must be selected for a clock period slightly greater than that of the external clock. RT is in kΩ CT is in mF f is in kHz If two or more UC1524 regulators are to operated synchronously, all oscillator output terminals should be tied together, all CT terminals connected to single timing capacitor, and the timing resistor connected to a single RT, terminal. Practical values of CT fall between 0.001mF and 0.1mF. Practical values of RT fall between 1.8kΩ and 100kΩ. This results in a frequency range typically from 120Hz to 500kHz. Blanking The output pulse of the oscillator is used as a blanking pulse at the output. This pulse width is controlled by the value of CT. If small values of CT are required for frequency control, the oscillator output pulse width may still be increased by applying a shunt capacitance of up to 100pF from pin 3 to ground. If still greater dead-time is required, it should be accomplished by limiting the maximum duty cycle by clamping the output of the error VREF 16 COMP 9 GND 8 1N916 5k Figure 1. Error amplifier clamp. The other RT terminals can be left open or shorted to VREF. Minimum lead lengths should be used between the CT terminals. Figure 2. Single-ended LC switching regulator circuit. 5 UC1524 UC2524 UC3524 V+ +28 V 15 5k 1k 1W VIN UC1524 5k 1 INV INPUT CA 12 2 NON INV INPUT EA 11 1k 1W 5V 5A 5k 0.1 F 2N4150 5k 100 16 VREF CB 13 6 RT EB 14 7 CT CLSENSE(+) 4 3 OSC OUT CLSENSE(-) 5 100 2k 20T 5T 20T 5T 2N4150 0.1 F 0.1 0.001 F 10 SD COMP 9 GND 500 F 50 k 8 Figure 3. Push-pull transformer coupled circuit. Figure 4. Open loop test circuit. UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 FAX (603) 424-3460 6 + 1500 F PACKAGE OPTION ADDENDUM www.ti.com 8-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty Lead/Ball Finish MSL Peak Temp (3) UC1524J OBSOLETE CDIP J 16 None Call TI Call TI UC1524J/80937 OBSOLETE CDIP J 16 None Call TI Call TI UC1524J883B OBSOLETE CDIP J 16 None Call TI Call TI UC2524DW ACTIVE SOIC DW 16 40 None CU NIPDAU Level-2-220C-1 YEAR UC2524DWTR ACTIVE SOIC DW 16 2000 None CU NIPDAU Level-2-220C-1 YEAR UC2524J OBSOLETE CDIP J 16 None Call TI UC2524N ACTIVE PDIP N 16 25 None CU SNPB UC3524D ACTIVE SOIC D 16 40 None CU NIPDAU Level-1-220C-UNLIM UC3524DTR ACTIVE SOIC D 16 2500 None CU NIPDAU Level-1-220C-UNLIM UC3524DW ACTIVE SOIC DW 16 40 None CU NIPDAU Level-2-220C-1 YEAR UC3524DWTR ACTIVE SOIC DW 16 2000 None CU NIPDAU Level-2-220C-1 YEAR UC3524J OBSOLETE CDIP J 16 UC3524N ACTIVE PDIP N 16 25 None Call TI None CU SNPB Call TI Level-NA-NA-NA Call TI Level-NA-NA-NA (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 - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. None: Not yet available Lead (Pb-Free). 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. Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens, including bromine (Br) or antimony (Sb) above 0.1% of total product weight. (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry 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. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security Telephony www.ti.com/telephony Video & Imaging www.ti.com/video Wireless www.ti.com/wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2005, Texas Instruments Incorporated