1.5A POWER SWITCHING REGULATOR 1.5A OUTPUT CURRENT 5.1V OUTPUT VO

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1.5A POWER SWITCHING REGULATOR 1.5A OUTPUT CURRENT 5.1V OUTPUT VO

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L4962
1.5A POWER SWITCHING REGULATOR
1.5A OUTPUT CURRENT 5.1V OUTPUT VOLTAGE RANGE PRECISE ON-CHIP REFERENCE HIGH SWITCHING FREQUENCY VERY HIGH EFFICIENCY 90%) VERY EXTERNAL COMPONENTS SOFT START INTERNAL LIMITING CURRENT THERMAL SHUTDOWN
POWERDIP
HEPTAWATT
ORDERING NUMBERS L4962/A Powerdip) L4962E/A (Heptawatt) L4962EH/A (Horizontal Heptawatt)
DESCRIPTION L4962 monolithic power switching regulator delivering 1.5A voltage variable from step down configuration. Features device include current limiting, soft start, thermal protection 100% duty cycle continuous operating mode.
L4962 mounted 16-lead Powerdip plastic package Heptawatt package requires very external components. Efficient operation switching frequencies 150KHz allows reduction size cost external filter components.
BLOCK DIAGRAM
Powerdip Heptawatt
March 1996
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L4962
ABSOLUTE MAXIMUM RATINGS
Symbol Input voltage Input output voltage difference Negative output voltage Output peak voltage 0.1µs; 100KHz V11, Ptot Tstg Voltage Voltage sink current source current Power dissipation Tpins 90°C (Powerdip) Tcase 90°C (Heptawatt) Junction storage temperature Parameter Value Unit
CONNECTION (Top view)
THERMAL DATA
Symbol j-case j-pins j-amb Parameter Thermal resistance junction-case Thermal resistance junction-pins Thermal resistance junction-ambient Heptawatt 4°C/W 50°C/W Powerdip 14°C/W 80°C/W*
Obtained with pins soldered printed circuit with minimized copper area.
FUNCTIONS
HEPTAWATT POWERDIP NAME SUPPLY VOLTAGE FUNCTION Unregulated voltage input. internal regulator powers internal logic. feedback terminal regulation loop. output connected directly this terminal 5.1V operation; connected divider higher voltages. series network connected between this terminal ground determines regulation loop gain characteristics.
FEEDBACK INPUT
FREQUENCY COMPENSATION
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L4962
FUNCTIONS (cont'd)
HEPTAWATT POWERDIP NAME GROUND OSCILLATOR FUNCTION Common ground terminal. parallel network connected this terminal determines switching frequency. This must connected input when internal oscillator used. Soft start time constant. capacitor connected between this terminal ground define soft start time constant. This capacitor also determines average short circuit output current. Regulator output. N.C.
SOFT START
OUTPUT
ELECTRICAL CHARACTERISTICS (Refer test circuit, 35V, unless otherwise specified)
Symbol Parameter Test Conditions Min. Typ. Max. Unit
DYNAMIC CHARACTERISTICS
Vref Vref Output voltage range Input voltage range Line regulation Load regulation Internal reference voltage (pin Average temperature coefficient refer. voltage Dropout voltage Maximum operating load current Current limiting threshold (pin Input average current Efficiency Vref Vref 1.5A Vref Vref
0.5A 1.5A
125°C 1.5A Vref Vref 46V; 100KHz output short-circuit Vref
mV/°C
Supply voltage ripple rejection
2Vrms fripple 100Hz Vref
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L4962
ELECTRICAL CHARACTERISTICS (continued)
Symbol Parameter Test Conditions Min. Typ. Max. Unit
DYNAMIC CHARACTERISTICS (cont'd)
fmax Switching frequency Voltage stability switching frequency Temperature stability switching frequency Maximum operating switching frequency Thermal shutdown junction temperature
125°C
Vref
CHARACTERISTICS
Quiescent drain current 100% duty cycle pins open duty cycle -I2L Output leakage current duty cycle
SOFT START
I15SO I15SI Source current Sink current
ERROR AMPLIFIER
V11H V11L I11SI -I11SO High level output voltage level output voltage Sink output current Source output current Input bias current open loop gain 4.7V 5.3V 5.3V 4.7V 5.2V 100µA 100µA
OSCILLATOR
-I14 Oscillator source current
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L4962
CIRCUIT OPERATION (refer block diagram) L4962 monolithic stepdown switching regulator providing output voltages from 5.1V delivering 1.5A. regulation loop consists sawtooth oscillator, error amplifier, comparator output stage. error signal produced comparing output voltage with precise 5.1V on-chip reference (zener trimmed 2%). This error signal then compared with sawtooth signal generate fixed frequency pulse width modulated pulses which drive output stage. gain frequency stability loop adjusted external network connected Closing loop directly gives output voltage 5.1V. 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. second comparator resets flip flop when voltage across soft start capacitor fallen 0.4V. output stage thus re-enabled output voltage rises under control soft start network. overload condition still present limiter will trigger again when threshold current reached. average short circuit current limited safe value dead time introduced soft start network. thermal overload circuit disables circuit operation when junction temperature reaches about 150°C hysteresis prevent unstable conditions.
Figure Soft start waveforms
Figure Current limiter waveforms
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L4962
Figure Test application circuit (Powerdip)
BYW98 Schottky diode, VRRM; CORE TYPE MAGNETICS 58120 TURNS WIRE GAUGE: 0.8mm AWG) ROE, 220µF
Figure Quiescent drain current supply voltage duty cycle)
Figure Quiescent drain current supply voltage (100% duty cycle)
Figure Quiescent drain current junction temperature duty cycle)
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L4962
Figure Quiescent drain current junction temperature (100% duty cycle) Figure Reference voltage (pin rdip) Figure Reference voltage (pin junction temperature
Figure Open loop frequency phase sponse error amplifier
gure Switching frequency input voltage
gure Switching frequency junction temperature
Figure Switching frequency (see test circuit)
gure Line transient response
Figure Load transient response
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L4962
Figure Supply voltage ripple rejection frequency Figure Dropout voltage between current Figure Dropout voltage etween junction temperature
Effi ciency output current
Effici ency output current
Effici ency output current
gure Effi ciency output voltage
Effici ency output voltage
Figure Maximum allowable power dissipation ambient temperature (Powerdip)
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L4962
APPLICATION INFORMATION Figure Typical application circuit
(ROE) BYW98 VISK340 (SCHOTTKY) SUGGESTED INDUCTORS: (L1) MAGNETICS 58120 A2MPP TURNS WIRE GAUGE 0.8mm (20AWG) COGEMA 946043 U15, GUP15, TURNS 1mm, 0.8mm AWG) COGEMA 969051.
Figure P.C. board component layout circuit Fig. scale)
Resistor values standard output voltages 4.7K 4.7K 4.7K 4.7K 6.2K 9.1K
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L4962
APPLICATION INFORMATION (continued) Figure minimal 5.1V fixed regulator; Very component required
COGEMA 946043 969051 (ROE)
(TOROID CORE) (U15 CORE)
Figure Programmable power supply
5.1V 1.5A Load regulation (0.5A 1.5A) 10mV 5.1V) Line regulation (220V 15mV 5.1V)
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L4962
APPLICATION INFORMATION (continued) Figure DC-DC converter 5.1V/4A, 12V/1A. suggestion synchronize negative output
COGEMA 946043 (969051) COGEMA 946044 (946045)
Figure multiple supplies several L4962s synchronized shown
Figure Preregulator distributed supplies
necessary reduce switching frequency spikes when linear regulators remote from L4962
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L4962
MOUNTING INSTRUCTION Rth-j-amb L4962 reduced soldering pins suitable copper area printed circuit board (Fig. 32). diagram figure shows Rth-j-amb function side equal square copper areas having thickness (1.4 mils). During soldering pins temperature must exceed 260°C soldering time must longer than seconds. external heatsink printed circuit copper must connected electrical ground.
Figure Example P.C. board copper area which used heatsink
Figure Maximum dissipable power junction ambient thermal resistance side
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L4962
POWERDIP PACKAGE MECHANICAL DATA
DIM. MIN. 3.30 1.27 8.80 2.54 17.78 7.10 5.10 0.130 0.050 0.38 0.51 0.85 0.50 0.50 20.0 0.346 0.100 0.700 0.280 0.201 0.015 1.40 TYP. MAX. MIN. 0.020 0.033 0.020 0.020 0.787 0.055 inch TYP. MAX.
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L4962
HEPTAWATT PACKAGE MECHANICAL DATA
DIM. MIN. 3.65 15.1 5.08 3.85 0.144 10.05 16.97 14.92 21.54 22.62 15.8 0.102 0.594 0.236 0.110 0.200 0.152 2.41 4.91 7.49 2.54 5.08 7.62 0.35 TYP. MAX. 1.37 1.35 0.55 2.67 5.21 10.4 10.4 0.396 0.668 0.587 0.848 0.891 0.118 0.622 0.260 0.095 0.193 0.295 0.100 0.200 0.300 0.094 0.047 0.014 0.024 MIN. inch TYP. MAX. 0.189 0.054 0.110 0.053 0.022 0.031 0.035 0.105 0.205 0.307 0.409 0.409
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L4962
Information furnished believed accurate reliable. However, SGS-THOMSON Microelectronics assumes responsibility consequences such information infringement patents other rights third parties which result from use. license granted implication otherwise under patent patent rights SGS-THOMSON Microelectronics. Specifications mentioned this publication subject change without notice. This publication supersedes replaces information previously supplied. SGS-THOMSON Microelectronics products authorized critical components life support devices systems without express written approval SGS-THOMSON Microelectronics. 1996 SGS-THOMSON Microelectronics Rights Reserved SGS-THOMSON Microelectronics GROUP COMPANIES Australia Brazil France Germany Hong Kong Italy Japan Korea Malaysia Malta Morocco Netherlands Singapore Spain Sweden Switzerland Taiwan Thaliand United Kingdom U.S.A.
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1.5A POWER SWITCHING REGULATOR 1.5A OUTPUT CURRENT 5.1V OUTPUT VO

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