SLUS168D – APRIL 1999 – REVISED AUGUST 2002 D Dual Output Drive Stages in Push-Pull D D D D D D D D OR N PACKAGE (TOP VIEW) Configuration 130-µA Typical Starting Current 1-mA Typical Run Current Operation to 1-MHz Internal Soft Start On Chip Error Amplifier With 2-MHz Gain Bandwidth Product On Chip VDD Clamping Output Drive Stages Capable Of 500-mA Peak Source Current, 1-A Peak Sink Current COMP FB CS RC 1 8 2 7 3 6 4 5 VDD OUTA OUTB GND PW PACKAGE (TOP VIEW) 1 2 3 4 OUTA VDD COMP FB description 8 7 6 5 OUTB GND RC CS The UCC3808 is a family of BiCMOS push-pull, high-speed, low-power, pulse-width modulators. The UCC3808 contains all of the control and drive circuitry required for off-line or dc-to-dc fixed frequency current-mode switching power supplies with minimal external parts count. The UCC3808 dual output drive stages are arranged in a push-pull configuration. Both outputs switch at half the oscillator frequency using a toggle flip-flop. The dead time between the two outputs is typically 60 ns to 200 ns depending on the values of the timing capacitor and resistors, thus limiting each output stage duty cycle to less than 50%. (continued) block diagram FB COMP CS 2 1 3 22 k Ω OVERCURRENT COMPARATOR PEAK CURRENT COMPARATOR 8 VDD 7 OUTA 6 OUTB 5 GND 14 V 0.75 V 0.5 V 2.0 V 2.2 V VDD OK OSCILLATOR S Q PWM LATCH R 1.2R VDD–1 V Q S S Q Q R R T Q PWM COMPARATOR VDD 0.5 V R SOFT START VOLTAGE REFERENCE SLOPE = 1 V/ms 4 Note: Pinout shown is for SOIC and PDIP packages. TSSOP pinout is different. RC UDG-02116 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 2002, Texas Instruments Incorporated ! " #$%! " &$'(# ! ) !%* )$#!" # ! "&%## !" &% !+% !%" %, " "!$%!" "! ) ) - !.* )$#! &#%""/ )%" ! %#%"" (. #($)% !%"!/ (( & %!%"* www.ti.com 1 SLUS168D – APRIL 1999 – REVISED AUGUST 2002 description (continued) The UCC3808 family offers a variety of package temperature range options, and choice of undervoltage lockout levels. The family has UVLO thresholds and hysteresis options for off-line and battery powered systems. Thresholds are shown in the table below. Table 1. Part Number Turn on Threshold Turn off Threshold UCCx808–1 12.5 V 8.3 V UCCx808–2 4.3 V 4.1 V ORDERING INFORMATION Packaged Devices TA = TJ 40°C to 85°C –40°C UVLO Option SOIC (D) PDIP (N) TSSOP (PW) 12.5 V/8.3 V UCC2808D–1 UCC2808N–1 UCC2808PW–1 4.3 V/4.1 V UCC2808D–2 UCC2808N–2 UCC2808PW–2 12.5 V/8.3 V UCC3808D–1 UCC3808N–1 UCC3808PW–1 0°C to 70°C 4.3 V/4.1 V UCC3808D–2 UCC3808N–2 UCC3808PW–2 † D (SOIC–8) and PW (TSSOP–8) packages are available taped and reeled. Add TR suffix to device type (e.g. UCC3808DTR–1) to order quantities of 2500 devices per reel for SOIC-8 and 2000 devices per reel for TSSOP-8. absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Supply voltage (IDD ≤ 10 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 V Supply current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA OUTA/OUTB source current (peak) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 A OUTA/OUTB sink current (peak) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 A Analog inputs (FB, CS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD+0.3 V, not to exceed 6 V Power dissipation at TA = 25°C (N Package) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 W Power dissipation at TA = 25°C (D Package) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 mW Power dissipation at TA = 25°C (PW Package) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 mW Storage temperature, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C Junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C Lead temperature (soldering, 10 sec.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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. ‡ Currents are positive into, negative out of the specified terminal. Consult Packaging Section of the Power Supply Control Data Book (TI Literature Number SLUD003) for thermal limitations and considerations of packages. 2 www.ti.com SLUS168D – APRIL 1999 – REVISED AUGUST 2002 electrical characteristics, TA = 0°C to 70°C for the UCC3808–x, –40°C to 85°C for the UCC2808–x and –55°C to 125°C for the UCC1808–x, VDD = 10 V (See Note 6), 1 µF capacitor from VDD to GND, R = 22 kΩ, C = 330 pF, TA = TJ, (unless otherwise specified) oscillator section PARAMETER TEST CONDITIONS Oscillator frequency Oscillator amplitude/VDD See Note 1 MIN TYP MAX UNITS 175 194 213 kHz 0.44 0.5 0.56 V/V error amplifier section PARAMETER Input voltage TEST CONDITIONS COMP = 2 V MIN 1.95 Input bias current –1 Open loop voltage gain 60 COMP sink current FB = 2.2 V, COMP = 1 V COMP source current FB = 1.3 V, COMP = 3.5 V TYP 2 MAX UNITS 2.05 V 1 µA 80 dB 0.3 2.5 mA –0.2 –0.5 mA PWM section PARAMETER TEST CONDITIONS Maximum duty cycle Measured at OUTA or OUTB Minimum duty cycle COMP = 0 V MIN 48% TYP 49% MAX UNITS 50% 0% current sense section PARAMETER TEST CONDITIONS Gain See Note 2 Maximum input signal COMP = 5 V, See Note 3 CS to output delay COMP = 3.5 V, CS from 0 to 600 mV CS source current TYP MAX CS = 0 V UNITS 1.9 2.2 2.5 0.45 0.5 0.55 V 100 200 ns 0.7 0.75 0.8 V 0.35 0.8 1.2 V –200 Over current threshold COMP to CS offset MIN V/V nA NOTES: 1. Measured at RC. Signal amplitude tracks VDD. DV COMP , 0 v V v 0.4 V, 2. Gain is defined by: A + CS DV CS 3. Parameter measured at trip point of latch with FB at 0V. 4. Start threshold and zener shunt threshold track one another. 5. For UCCx808–1, set VDD above the start threshold before setting at 10 V. 6. Does not include current in the external oscillator network. www.ti.com 3 SLUS168D – APRIL 1999 – REVISED AUGUST 2002 electrical characteristics, TA = 0°C to 70°C for the UCC3808–x, –40°C to 85°C for the UCC2808–x and –55°C to 125°C for the UCC1808–x, VDD = 10 V (See Note 6), 1 µF capacitor from VDD to GND, R = 22 kΩ, C = 330 pF, TA = TJ, (unless otherwise specified) output section PARAMETER TEST CONDITIONS OUT low level I = 100 mA OUT high level I = –50 mA, Rise time Fall time MIN TYP MAX UNITS 0.5 1 V 0.5 1 V CL = 1 nF 25 60 ns CL = 1 nF 25 60 ns VDD – OUT undervoltage lockout section PARAMETER TEST CONDITIONS UCCx808–1, Start threshold Minim m operating voltage Minimum oltage after start H steresis Hysteresis MIN See Note 6 TYP MAX UNITS 11.5 12.5 13.5 V UCCx808–2 4.1 4.3 4.5 V UCCx808–1 7.6 8.3 9 V UCCx808–2 3.9 4.1 4.3 V UCCx808–1 3.5 4.2 5.1 V UCCx808–2 0.1 0.2 0.3 V soft start section PARAMETER COMP rise time TEST CONDITIONS FB = 1.8 V, MIN rise from 0.5 V to 4 V TYP 3.5 MAX 20 UNITS ms overall section PARAMETER TEST CONDITIONS Startup current VDD < start threshold Operating supply current FB = 0 V, CS = 0 V, VDD zener shunt voltage IDD = 10 mA, See Note 4 MIN See Note 5 and 6 www.ti.com 13 MAX UNITS 260 µA 1 2 mA 14 15 V 130 NOTES: 1. Measured at RC. Signal amplitude tracks VDD. DV COMP , 0 v V v 0.4 V, 2. Gain is defined by: A + CS DV CS 3. Parameter measured at trip point of latch with FB at 0V. 4. Start threshold and zener shunt threshold track one another. 5. For UCCx808–1, set VDD above the start threshold before setting at 10 V. 6. Does not include current in the external oscillator network. 4 TYP SLUS168D – APRIL 1999 – REVISED AUGUST 2002 pin descriptions COMP: COMP is the output of the error amplifier and the input of the PWM comparator. The error amplifier in the UCC3808 is a true low-output impedance, 2-MHz operational amplifier. As such, the COMP pin can both source and sink current. However, the error amplifier is internally current limited, so that zero duty cycle can be externally forced by pulling COMP to GND. The UCC3808 family features built-in full cycle soft start. Soft start is implemented as a clamp on the maximum COMP voltage. CS: The input to the PWM, peak current, and overcurrent comparators. The overcurrent comparator is only intended for fault sensing. Exceeding the overcurrent threshold will cause a soft start cycle. FB: The inverting input to the error amplifier. For best stability, keep FB lead length as short as possible and FB stray capacitance as small as possible. GND: Reference ground and power ground for all functions. Due to high currents, and high frequency operation of the UCC3808, a low impedance circuit board ground plane is highly recommended. OUTA and OUTB: Alternating high current output stages. Both stages are capable of driving the gate of a power MOSFET. Each stage is capable of 500-mA peak source current, and 1-A peak sink current. The output stages switch at half the oscillator frequency, in a push/pull configuration. When the voltage on the RC pin is rising, one of the two outputs is high, but during fall time, both outputs are off. This dead time between the two outputs, along with a slower output rise time than fall time, insures that the two outputs can not be on at the same time. This dead time is typically 60 ns to 200 ns and depends upon the values of the timing capacitor and resistor. The high-current output drivers consist of MOSFET output devices, which switch from VDD to GND. Each output stage also provides a very low impedance to overshoot and undershoot. This means that in many cases, external schottky clamp diodes are not required. RC: The oscillator programming pin. The UCC3808’s oscillator tracks VDD and GND internally, so that variations in power supply rails minimally affect frequency stability. Figure 1 shows the oscillator block diagram. Only two components are required to program the oscillator: a resistor (tied to the VDD and RC), and a capacitor (tied to the RC and GND). The approximate oscillator frequency is determined by the simple formula: f OSCILLATOR + 1.41 RC where frequency is in hertz, resistance in ohms, and capacitance in farads. The recommended range of timing resistors is between 10 kΩ and 200 kΩ and range of timing capacitors is between 100 pF and 1000 pF. Timing resistors less than 10 kΩ should be avoided. For best performance, keep the timing capacitor lead to GND as short as possible, the timing resistor lead from VDD as short as possible, and the leads between timing components and RC as short as possible. Separate ground and VDD traces to the external timing network are encouraged. VDD: The power input connection for this device. Although quiescent VDD current is very low, total supply current will be higher, depending on OUTA and OUTB current, and the programmed oscillator frequency. Total VDD current is the sum of quiescent VDD current and the average OUT current. Knowing the operating frequency and the MOSFET gate charge (Qg), average OUT current can be calculated from: I OUT + Qg F, where F is frequency To prevent noise problems, bypass VDD to GND with a ceramic capacitor as close to the chip as possible along with an electrolytic capacitor. A 1-µF decoupling capacitor is recommended. www.ti.com 5 SLUS168D – APRIL 1999 – REVISED AUGUST 2002 pin descriptions (continued) UDG–97009 NOTE: The oscillator generates a sawtooth waveform on RC. During the RC rise time, the output stages alternate on time, but both stages are off during the RC fall time. The output stages switch a ½ the oscillator frequency, with guaranteed duty cycle of < 50% for both outputs. Figure 1. Block Diagram for Oscillator APPLICATION INFORMATION A 200-kHz push-pull application circuit with a full wave rectifier is shown in Figure 2. The output, VO, provides 5 V at 75 W maximum and is electrically isolated from the input. Since the UCC3808 is a peak current mode controller the 2N2222A emitter following amplifier (buffers the CT waveform) provides slope compensation which is necessary for duty ratios greater than 50%. Capacitor decoupling is very important with a single ground IC controller, and a 1 µF is suggested as close to the IC as possible. The controller supply is a series RC for start-up, paralleled with a bias winding on the output inductor used in steady state operation. Isolation is provided by an optocoupler with regulation done on the secondary side using the UC3965 Precision Reference with Low Offset Error Amplifier. Small signal compensation with tight voltage regulation is achieved using this part on the secondary side. Many choices exist for the output inductor depending on cost, volume, and mechanicall strength. Several design options are iron powder, molypermalloy (MPP), or a ferrite core with an air gap as shown here. The main power transformer is a low profile design, EFD size 25, using Magnetics Inc. P material which is a good choice at this frequency and temperature. The input voltage may range from 36 V dc to 72 V dc. 6 www.ti.com ER28 8:2 32CTQ030 NS1 NP1 NS2 EF25 7µH 680 µF 0.01 µF VIN 36 V TO 72 V – LOOP B + 4700 µF 0.47 µF 1000 pF – BYV 28–200 62 Ω 62 Ω BYV 28–200 1000 pF 200 Ω LOOP A COMP 51 kΩ 1/4 W 19.1 kΩ IRF640 IRF640 4700 pF 20 kΩ 12 10 Ω 2.2 Ω 470 pF DF02SGICT 2.2 Ω 1 mH 3 10 µF 0.1 µF 2 19.1 kΩ 2 kΩ 0.2 Ω 20 kΩ VDD 8 330 pF OUTA OUTB GND 7 6 PRIMARY GROUND 5 UCC3808D-1 1 2 COMP FB 3 CS 240 Ω 4 RC RC 4.99 kΩ 86.6 kΩ CURRENT SENSE 4.99 kΩ 2N2907 4 H11A1 U3 3 5 2 6 1 20 kΩ 330 pF 432 Ω 0.1 µF 0.01 µF 1 kV UDG-00142 7 SLUS168D – APRIL 1999 – REVISED AUGUST 2002 2.80 kΩ 1 TL431 0.1 µF APPLICATION INFORMATION www.ti.com Figure 2. Typical Application Diagram: 48-V In, 5-V, 50-W Output NP2 VO 5 V 50 W + SLUS168D – APRIL 1999 – REVISED AUGUST 2002 APPLICATION INFORMATION FREQUENCY vs TIMING RESISTOR IDD vs OSCILLATOR FREQUENCY CS OFFSET vs TEMPERATURE 1.2 1000 14 C CT=100pF 10 100 IDD – mA Frequency – kHz CT=330pF CT=220pF IDD With 1 nF Load 8 6 0.6 4 IDD Without Load CT=560pF 2 0 0.2 0 0 0 50 100 150 200 250 0 200 600 400 800 1000 1200 –55 –35 –15 5 25 45 RT – Timing Resistor – kΩ Oscillator Frequency – kHz Temperature – °C Figure 3 Figure 4 Figure 5 ERROR AMPLIFIER GAIN AND PHASE RESPONSE vs FREQUENCY DEAD TIME vs TIMING RESISTOR 90 180 80 160 120 CT=1000pF 140 60 120 Phase 50 100 40 80 30 60 20 Dead Time – ns 70 Phase Margin - Degrees 100 Gain dB 0.8 CT=1000pF CT=820pF CT=820pF 80 CT=560pF 60 40 CT=100pF CT=220pF CT=330pF 40 20 Gain 10 20 0 8 1.0 0.4 10 0 1 COMP – CS Offset – V VDD = 10 V, T = 25 12 100 10000 1000000 0 0 20 40 60 Frequency – Hz RT – Timing Resistor – kΩ Figure 6 Figure 7 www.ti.com 80 100 65 85 105 125 PACKAGE OPTION ADDENDUM www.ti.com 11-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty HPA00002DTR ACTIVE SOIC D 8 UCC2808D-1 ACTIVE SOIC D 8 Lead/Ball Finish MSL Peak Temp (3) None CU NIPDAU Level-1-220C-UNLIM 75 None CU NIPDAU Level-1-220C-UNLIM UCC2808D-2 ACTIVE SOIC D 8 75 None CU NIPDAU Level-1-220C-UNLIM UCC2808DTR-1 ACTIVE SOIC D 8 2500 None CU NIPDAU Level-1-220C-UNLIM UCC2808DTR-2 ACTIVE SOIC D 8 2500 None CU NIPDAU Level-1-220C-UNLIM UCC2808DTR-2/1G4 PREVIEW SOIC D 8 2500 None Call TI Call TI UCC2808DTR-2G4 PREVIEW SOIC D 8 2500 None Call TI Call TI UCC2808N-1 ACTIVE PDIP P 8 50 Pb-Free (RoHS) CU NIPDAU Level-NC-NC-NC UCC2808N-2 ACTIVE PDIP P 8 50 Pb-Free (RoHS) CU NIPDAU Level-NC-NC-NC UCC2808N-2G4 ACTIVE PDIP P 8 50 None Call TI UCC3808D-1 ACTIVE SOIC D 8 75 None CU NIPDAU Level-1-220C-UNLIM UCC3808D-2 ACTIVE SOIC D 8 75 None CU NIPDAU Level-1-220C-UNLIM UCC3808DTR-1 ACTIVE SOIC D 8 2500 None CU NIPDAU Level-1-220C-UNLIM UCC3808DTR-2 ACTIVE SOIC D 8 2500 None CU NIPDAU Level-1-220C-UNLIM UCC3808N-1 ACTIVE PDIP P 8 50 Pb-Free (RoHS) CU NIPDAU Level-NC-NC-NC UCC3808N-2 ACTIVE PDIP P 8 50 Pb-Free (RoHS) CU NIPDAU Level-NC-NC-NC Call TI (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. 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