HIGH CURRENT SWITCHING REGULATOR OUTPUT CURRENT OUTPUT VOLTAGE RA
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L4964
HIGH CURRENT SWITCHING REGULATOR
OUTPUT CURRENT OUTPUT VOLTAGE RANGE DUTY CYCLE RANGE PRECISE ON-CHIP REFERENCE SWITCHING FREQUENCY VERY HIGH EFFICIENCY VERY EXTERNAL COMPONENTS SOFT START RESET OUTPUT CURRENT LIMITING INPUT REMOTE INHIBIT SYNCHRONUS THERMAL SHUTDOWN
MULTIWATT15 Vertical (Plastic Package) ORDERING NUMBER L4964
DESCRIPTION L4964 stepdown power switching regulator delivering voltage variable from 5.1V 28V. Features device include overload protection, soft start, remote inhibit, thermal protection, reset output microprocessors comparator input synchronization multichip configurations. L4964 mounted 15-lead Multiwatt® plastic power package requires very external components. Efficient operation switching frequencies 120kHz allows reduction size cost external filter components. CONNECTION (top view)
MULTIWATT15 Horizontal (Plastic Package) ORDERING NUMBER L4964HT
Pins must connected. Leave open circuit.
July 2003
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L4964
FUNCTIONS
Name N.C. Output Supply Voltage N.C. Soft Start Regulator Output. Unregulated Voltage Input. internal regulator powers L4964's internal logic. Must connected. Leave open circuit. Soft Start Time Constant. capacitor connected between this terminal ground define soft start time constant. This capacitor also determines average short circuit output current. Level Remote Inhibit. logic high level this input disables L4964. Multiple L4964's synchronized connecting inputs together omitting oscillator network device. Common Ground Terminal. series network connected between this terminal ground determines regulation loop gain characteristics. Feedback Terminal Regulation Loop. output connected directly this terminal operation connected divider higher voltages. parallel network connected this terminal determines switching frequency. must connected input when internal oscillator used. Input Reset Circuit. threshold roughly connected beedback point divider input. capacitor connected between this terminal ground determines reset signal delay time. Open Collector Reset Signal Output. This output high when supply safe. Must connected. Leave open circuit. Function Must connected. Leave open circuit.
Inhibit Input Sync Input Ground Frequency Compensation Feedback Input Oscillator Reset Input Reset Delay Reset Output N.C.
BLOCK DIAGRAM
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L4964
CIRCUIT OPERATION (refer block diagram) L4964 monolithic stepdown switching regulator providing output voltages from delivering regulation loop consists sawtooth oscillator, error amplifier, comparator output stage. error signal produced comparing output voltage with precise on-chip reference (zener trimmed This error signal then compared with sawtooth signal generate fixed frequency pulse width modulated pulses which drive output stage. gain frequency stability loop ajusted external network connected Closing loop directly gives output voltage Higher voltages obtained inserting voltage divider. Output overcurrents switch prevented soft start function. error amplifier output initially clamped external capacitor allowed rise, linearly, this capacitor charged constant current source. Output overload protection provided form current limiter. load current sensed internal metal resistor connected comparator. When load current exceeds preset threshold this comparator sets flip flop which disables output stage discharges soft start capacitor. Figure Reset Output Waveforms second comparator resets flip flop when voltage across soft start capacitor fallen output stage thus re-enable output voltage rises under contro soft start network. overload condition still present limiter will trigger again when thershold current reached. average short circuit current limited safe value dead time introduced soft start network. reset circuit generates output signal when supply voltage exceeds threshold programmed external divider. reset signal generated with delay time programmed external capacitor. When supply falls below threshold reset output goes immediately. reset output open collector. level input provided applications such remote on/off control. This input activated high level disables circuit operation. After inhibit L4964 restarts under control soft start network. thermal overload circuit disables circuit operation when junction temperature reaches about hysteresis prevent unstable conditions.
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L4964
Figure Soft Start Waveforms
Figure Current Limiter Waveforms
ABSOLUTE MAXIMUM RATINGS
Symbol V10, Ptot Tstg Parameter Input Voltage (pin Input Output Voltage Difference Output Voltage Output Peak Voltage µsec Voltage Voltage Pins Voltage Pins Voltage (I14 Sink Current Source Current Sink Current (V14 Power Dissipation Tcase Junction Storage Temperature Value Unit
THERMAL DATA
Symbol j-case j-amb 4/13 Parameter Thermal Resistance Junction-case Thermal Resistance Junction-ambient Max. Max. Value Unit °C/W °C/W
L4964
ELECTRICAL CHARACTERISTICS (refer test circuits 25oC, 25V, unless otherwise specified)
Symbol Vref Vref fmax Parameter Output Voltage Range Input Voltage Range Line Regulation Load Regulation Test Conditions Min. Typ. Max. 5.25 Unit mV/°C Fig. DYNAMIC CHARACTERISTICS (pin unless otherwise specified) 36V, Vref Vref 28V, 30V, Vref, 0.5A Vref Internal Reference Voltage (Pin 36V, 4.95 Average Temperature Coefficient 125°C, Reference Voltage Dropout Voltage between Maximum Operating Load Current Current Limiting Threshold (Pin Input Average Current Efficiency Supply Voltage Ripple Rejection Switching Frequency Voltage Stability Switching Frequency Temperature Stability Switching Frequency Maximum Operating Switching Frequency Thermal Shutdown Junction Temperature Quiescent Drain Current 36V, Vref 36V, Vref 36V, Output Short-circuited Vref 2Vrms, fripple 100Hz Vref, 125°C Vref,
CHARACTERISTICS -I2L 36V, 36V, 36V, 36V, 0.8V 4.7V, 5.3V, 5.3V, 4.7V, 100µA, 100µA,
Output Leakage Current
SOFT START I5so I5si INHIBIT -I6H Input Voltage High Input Voltage Input Current with Input Voltage Level High Level High Level Output Voltage Level Output Voltage Sink Output Current Source Output Current Source Current Sink Current
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ERROR AMPLIFIER
L4964
ELECTRICAL CHARACTERISTICS (continued) (refer test circuits 25oC, 25V, unless otherwise specified)
Symbol -I11 RESET V12R V12F V13D V13H V14S -I13 Rising Threshold Voltage Falling Threshold Voltage Delay Threshold Voltage Delay Threshold Voltage Hysteresis Output Saturation Volt. Input Bias Current Delay Source Current Delay Sink Current Output Leakage Current Vref Vref Vref 150mV 100mV 50mV Vref 4.75 Vref 150mV 100mV Parameter Input Bias Current Open Loop Gain Test Conditions 5.2V, Min. Typ. Max. Unit Fig. ERROR AMPLIFIER (continued)
OSCILLATOR COMPARATOR Input Bias Current 0.5V 3.5V Comparator Oscillator Source Current
5mA, 4.7V Vref, 5.3V 4.7V 36V, 5.3V,
Figure Dynamic Test Circuit
(ROE)
Core type MAGNETICS 58930 turns Wire Gauge AWG)
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L4964
Figure Board Component Layout Circuit Fig. (1:1 scale)
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L4964
Figure Test Circuits. Figure Figure
Figure
Change obtain
Figure
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L4964
Figure Switching Frequency (see fig. Figure Open Loop Frequency Phase Response Error Amplifier (see fig. 6c).
Figure Reference Voltage (pin Junction Temperature (see fig.
Figure Power Dissipation (L4964 only) Input Voltage.
Figure Efficiency Output Voltage.
Figure Power Dissipation Derrating Curve.
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L4964
APPLICATION INFORMATION CHOOSING INDUCTOR CAPACITOR input output capacitors L4964 must have inductance high current ripple. Preferably, inductor should toroidal type wound Moly-Permalloy nucleus.Saturation must occur current levels below times Figure Typical Application Circuit. current limiter level. nuclei have very soft saturation characteristics.
Inductance current ripple Output ripple voltage
4964
(ROE)
SUGGESTED INDUCTOR (L1)
Core Type Turns Wire Gauge (mmm) (mm)
Resistor Values Standard Output Voltages
Magnetics 58930 A2MPP Thomson Siemens 35/17/10 (B6633& G0500 X127) VOGT Toroidal Coil, Part Number 5730501800
Figure P.C. Board Component Layout Circuit Fig. (1:1 scale)
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L4964
DIM. MIN. Dia1 3.65 0.49 0.66 1.02 17.53 19.6 19.6 17.8 17.25 10.3 2.65
TYP. MAX. 2.65 0.55 0.75 1.27 17.78 1.52 18.03 20.2 20.2 17.5 10.7 18.2 17.75 10.9 3.85 0.075 0.075 0.144 0.019 0.026 0.040 0.690 0.772 0.772 0.701 0.091 0.679 0.406 0.106 0.104 MIN.
inch TYP. MAX. 0.197 0.104 0.063 0.022 0.030 0.050 0.060
OUTLINE MECHANICAL DATA
0.700 18.030 0.795 0.795 0.709 0.098 0.689 0.421 0.118 0.717 0.110 0.699 0.429 0.130 0.114 0.059 0.102 0.102 0.152
MUL15V.TBL
Multiwatt15 (Short Leads)
Diam
MW15HME
11/13
L4964
DIM. MIN. Dia1 21.9 21.7 17.65 17.25 10.3 2.65 4.25 4.63 3.65 0.49 0.66 1.02 17.53 19.6
TYP. MAX. 2.65 0.55 0.75 1.27 17.78 1.52 18.03 20.2 22.2 22.1 17.5 10.7 4.55 5.08 22.5 22.5 18.1 17.75 10.9 4.85 5.53 3.85 0.862 0.854 0.695 0.679 0.406 0.104 0.167 0.182 0.075 0.075 0.144 0.019 0.026 0.040 0.690 0.772 MIN.
inch TYP. MAX. 0.197 0.104 0.063 0.039 0.022 0.030 0.050 0.700 0.060 0.710 0.795 0.874 0.870 0.689 0.421 0.179 0.200 0.886 0.886 0.713 0.699 0.429 0.191 0.218 0.102 0.102 0.152
MUL15H.TBL
OUTLINE MECHANICAL DATA
0.114
Multiwatt15
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L4964
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