L4964
July 2003
HIGH CURRENT SWITCHING REG ULATO R
®
.4 A OUTPUT C URRENT
.5.1 V TO 28 V OUTPUT VOLTAGE RANGE
.0 TO 100 % DUT Y C Y CLE R A NG E
.PRECISE (± 3 %) ON-CHIP REFERENCE
.SW ITCHING FREQU ENC Y UP TO 120 K Hz
.VERY H IGH EFFICIEN CY (UP TO 90 %)
.VERY FEW EXTERNAL COMPONENTS
.SOFT START
.RESET OUT P UT
.CURRENT L IMITING
.INPUT FOR REMOTE INHIBIT AND SYN-
CHRONUS PWM
.THERMAL SHUTDOWN
DESCRIPTION
The L4964 is a stepdown power switchi ng regula tor
deliv ering 4A at a voltage variable from 5.1V to 28V.
Fe atur es of the dev ic e inc l ude ov er load protec t ion ,
soft s tar t , re m ot e i nhibit, thermal pr otec t ion , a re se t
output for micro processors and a PW M com parator
input for synchronization in multichip configurations.
The L4964 is mou nted in a 15-le ad Multiwatt plas-
tic power package and requires very few external
components.
Efficient operation at switching frequencies up to
120kHz allows a reduction in the size and cost of ex-
ternal filter co mp one nt s.
MULTIWATT15 Vertical
(Plastic Package)
ORDERING NUMBER : L4964
MULTIWATT15 Horizontal
(Plastic Package)
ORDERING NUMBER : L4964HT
Pi ns 1, 4, 15 mu st no t b e connect ed. Le av e open circuit.
PIN CONNECTION (top view)
1/13
PIN FUNCTION S
N°Name Function
1 N.C. Must not be connected. Leave open circuit.
2 Output Regulator Output.
3 Supply Voltage Unregulated Voltage Input. An internal regulator pow ers the L4964’s internal logic.
4 N.C. Must not be connected. Leave open circuit.
5 Soft Start Soft Start Time Constant. A capacitor is connected between this terminal and ground
to define the s oft start time constant. This capacitor also determines the average short
circuit output current.
6 Inhibit Input TTL - Level Remote Inhibit. A logic high level on this input disables the L4964.
7 Sync Input Multiple L4964’s are synchronized by connecting the pin 7 inputs together and omitting
the oscillator RC network on all but one device.
8 Ground Common Ground Terminal.
9 Frequency
Compensation A series RC network connected between this terminal and ground determines the
regulation loop gain characteristics.
10 Feedback
Input The Feedback Terminal of the Regulation Loop. The output is connected directly to
this terminal for 5.1 V operation ; it is connected via a divider for higher voltages.
11 Os cillator A parallel RC network connected to this terminal determines the switching frequency.
The pin must be connected to pin 7 input when the internal oscillator is used.
12 Reset Input Input of the Reset Circuit. The threshold is roughly 5 V. It may be connected to the
beedback point or via a divider to the input.
13 Reset Delay A capacitor connected between this terminal and ground determines the reset signal
delay time.
14 Reset Output Open Collector Reset Signal Output. This output is high when the supply is safe.
15 N.C. Must not be connected. Leave open circuit.
BLOCK DIAGRAM
L4964
2/13
CIRCUIT O PERATION (refer to th e block diagram)
The L4964 is a monolithic stepdown switching regu-
lator providing output voltages from 5.1 V to 28 V
and delivering 4A.
The regulation loop consists of a sawtooth oscillator,
error amplifier, comparator and the output stage. An
error signal is produced by comparing the output
voltage with a precise 5.1 V on-chip reference
(zener zap trimmed to ± 3 %). This error signal is
then compared with the sawtooth signal to generate
the fixed frequency pulse width modulated pulses
which drive the output stage. The gain and fre-
quenc y stability of the loop can be a justed by an ex-
ternal RC network connected to pin 9. Closing the
loop directly gives an output voltage of 5.1 V. Higher
voltages are obtained by inserting a voltage divider.
Output overcurrents at switch on are prevented by
the soft start function. The error amplifier output is
initially clamped by the external capacitor Css and al-
lowed to rise, linearly, as this capacitor is charged
by a c on stant curr ent s our c e.
Output overload protection is provided in the form of
a current limiter. The load current is sensed by an
internal metal resistor connected to a comparator.
When the load current exceeds a preset threshold
this comparator sets a flip flop which disables the
output stage and discharges the soft start capacitor.
A second comparator resets the flip flop when the
voltage across the soft start capacitor has fallen to
0.4 V. The output stage is thus re-enable and the
output voltage rises under contro of the soft start net-
work. If the overload condition is still present the
limiter will trigger again when the thershold curr ent
is reac he d. The av er age s ho rt c ir cu it cu rr en t is lim-
it ed to a safe va lue by the dead time int r odu c ed by
th e so ft st ar t net wor k .
The reset circuit generates an output signal when
the supply voltage exceeds a threshold pro-
gra mme d by an e xterna l divi der. The rese t signal is
gene rate d with a delay time pr ogram med by an ex-
ternal capacitor. When the supply falls below the
threshold the reset output goes low immediately.
T he r es et out pu t is an o pen collector .
A TT L - level input is provid ed for applic atio ns such
as remote on/off cont rol. This input is ac tivat ed by
high level and d isables circuit operatio n. After an in-
hibit the L4964 restarts under control of the soft start
network.
The thermal overload circuit disables circuit opera-
tion when the junction temperature reaches about
150 and has hysteresis to prevent unst able condi-
tions.
F ig ure 1 : Rese t Output Waveforms
L4964
3/13
F ig ure 2 : S oft Start Waveforms
Figure 3 : Curre nt Lim iter W av e fo rms
ABSOLUTE MAXIMUM RAT INGS
Symbol Parameter Value Unit
ViInput Voltage (pin 3) 36 V
Vi – V2Input to Output Voltage Difference 38 V
V2Output DC Voltage
Output Peak Voltage at t = 0.1 µsec f = 100 kHz –1
–7 V
V
V12 Voltage at Pin 12 10 V
V5, V7, V9Voltage at Pins 5, 7 and 9 5.5 V
V10, V6, V13 Voltage at Pins 10, 6 and 13 7 V
V14 Voltage at Pin 14 (I14 ≤ 1 mA) Vi
I9Pin 9 Sink Current 1 m A
I11 Pin 11 Source Current 20 m A
I14 Pin 14 Sink Current (V14 < 5 V) 50 m A
Ptot Power Dissipation at Tcase ≤ 90 °C20W
T
j
, Tstg Junction and Storage Temperature – 40 to 150 °C
THERMAL DATA
Symbol Parameter Value Unit
Rth j-case Thermal Resistance Junction-case Max. 3 °C/W
Rth j-amb Thermal Resistance Junction-ambient Max. 35 °C/W
L4964
4/13
ELECTRICAL CHARACTERISTICS
(refer to the test circuits Tj = 25oC, V i = 25V, unle ss otherwise specified)
Symbol Parameter Test Conditions Min. Typ. Max. Unit Fig.
DYNAMIC CHARACTERISTICS (pin 6 to GND unless otherwise specified)
VoOutput Voltage Range Vi = 36V, Io = 1A Vref 28V4
V
iInput Voltage Range Vo = Vref to 28V, Io = 3A 9 36 V 4
∆VoLine Regulation Vi = 10V to 30V, Vo = Vref, Io = 2A 15 70 mV 4
∆VoLoad Regulation Io = 1A to 2A
Io = 0.5A to 3A, Vo = Vref 10
15 30
50 mV
mV 4
4
Vref Internal Reference Voltage (Pin 10) Vi = 9V to 36V, Io = 2A 4.95 5.1 5.25 V 4
∆Vref
∆TAverage Temperature Coefficient
of R eference Voltage Tj = 0°C to 125°C, Io = 2A 0.4 mV/°C
VdDropout Voltage between Pin 2
and Pin 3 Io = 3A
Io = 2A 2
1.5 3.2
2.4 V
V4
4
IomMaximum Operating Load Current VI = 9V to 36V, Vo = Vref to 28V 4 A 4
I2L Current Limiting Threshold (Pin 2) V i = 9V to 36V, Vo = Vref to 28V 4.5 8 A 4
ISH Input Average C urrent Vi = 36V, Output Short-circuited 80 140 mA 4
ηEfficiency Io = 3A Vo = Vref
Vo = 12V 75
85 %
%4
4
SVR Supply Voltage Ripple R ejection ∆VI = 2Vrms, fripple = 100Hz
Vo = Vref, Io = 2A 46 56 – dB 4
f Switching Frequency 40 50 60 kHz 4
∆f
∆Vi
Voltage Stability of Switching
Frequency Vi = 9V to 36V 0.5 % 4
∆f
∆Tj
Temperature Stability of Switching
Frequency Tj = 0°C to 125°C1%4
f
max Maximum Operating Switching
Frequency Vo = Vref, Io = 1A 120 kHz –
Tsd Thermal Shutdown Junction
Temperature 135 145 °C–
DC CHARACTERISTICS
I3Q Quiescent Drain C urrent Vi = 36V, V 7 = 0V, S1 : B, S2 : B
V6 = 0V
V6 = 3V 66
30 100
50
mA 6a
–I2L Output Leakage Current Vi = 36V, V6 = 3 V, V7 = 0V
S1 : B, S2 : A 2mA6a
SOFT START
I5so Source Current V6 = 0V, V5 = 3V 80 130 180 µA6b
I
5si Sink Current V6 = 3V, V5 = 3V 40 70 140 µA6b
INHIBIT
V6L Low Input Voltage Vi = 9V to 36V, V7 = 0V
S1 : B, S2 : B - 0.3 0.8 V 6a
V6H High Input Voltage 2 5.5 V 6a
– I6L
–I6H
Input Current w ith Input Voltage
Low Level
High Level
Vi = 9V to 36V, V7 = 0V
S1 : B, S2 : B
V6 = 0.8V
V6 = 2V 20
10
µA6a
ERROR AMPLIFIER
V9H High Level Output Voltage V10 = 4.7V, I9 = 100µA, S1 : A,
S2 : A 3.4 V 6c
V9L Low Level Output Voltage V10 = 5.3V, I 9 = 100µA, S1 : A,
S2 : E 0.6 V 6c
I9 si Sink Output Current V10 = 5.3V, S1 : A, S2 : B 100 150 µA6c
–I9 so Source Output Current V10 = 4.7V, S1 : A, S2 : D 100 150 µA6c
L4964
5/13
ELECTRICAL CHARACTERISTICS (continued)
(refer to the test circuits Tj = 25oC, V i = 25V, unle ss otherwise specified)
Symbol Parameter Test Conditions Min. Typ. Max. Unit Fig.
ERROR AMPLIFIER (continued)
I10 Input Bias Current V10 = 5.2V, S1 : B 2 20 µA6c
G
vDC Open Loop Gain V9 = 1V to 3V, S1 : A, S2 : C 40 55 dB 6c
OSCILLATOR AND PWM COMPARATOR
–I7Input Bias Current of
PWM Comparator V7 = 0.5V to 3.5V 10 µA6a
–I11 Oscillator Source Current V11 = 2V, S1 : A, S2 : B 4 – m A 6a
RESET
V12R Rising Threshold Voltage Vi = 9 V to 36 V, S1 : B, S2 : B Vref
- 150mV Vref
- 100mV Vref
- 50mV V6d
V
12F Falling Threshold Voltage 4.75 Vref
- 150mV Vref
- 100mV V6d
V
13D Delay Threshold Voltage V12 = 5.3 V, S1 : A, S2 : B 4.3 4.5 4.7 V 6d
V13H Delay Threshold Voltage
Hysteresis 100 mV 6d
V14S Output Saturation Volt. I14 = 5mA, V12 = 4.7V - S1, S2 : B 0.4 V 6d
I12 Input Bias Current V12 = 0V to Vref, S1 : B, S2 : B 1 10 µA6d
–I13 so
I13 si Delay Source Current
Delay Sink Current
V13 = 3V, S1 : A, S2 : B
V12 = 5.3V
V12 = 4.7V 60
8110 150 µA
mA
6d
I14 Output Leakage Current Vi = 36V, V12 = 5.3V, S1 : B, S2 : A 100 µA6d
C7, C8 : EKR (ROE)
L1 : L = 30 0 µH at 8 A
R = 500 mΩCore type : MAGNE TICS 58930 - A2 MP P
N° turns : 43 Wire Gauge : 1 mm (18 AWG)
Figure 4 : Dynam ic T es t Cir c uit
L4964
6/13
Figure 5 : PC. Bo ar d and Com ponent La yo ut of the Cir c uit of F ig . 4 (1: 1 s c ale )
L4964
7/13
F ig ure 6 : DC Test Circuits.
Figure 6a. Figur e 6b.
F ig ure 6c.
1 - Set V 10 FOR V9 = 1 V
2 - Change V 10 to obtain V9 = 3 V
3 - GV = DV9 = 2 V
∆V10 ∆V10
F ig ure 6d.
L4964
8/13
F ig ure 7 : S wit c hi ng F r equ enc y vs . R1 ( s ee f ig. 4) . Figur e 8 : Open Loop F r eq uency and P has e Re s -
ponse of Er ro r A m pli f ier (see fig . 6c).
F ig ure 9 : Ref e ren c e V olt ag e (p in 10) vs . Jun c-
tion T emperature (see fig. 4). Figur e 10 : Power Dis sipat io n (L 4964 only) v s.
Input Volt age.
F ig ure 11 : Eff ic ienc y v s. Output V oltage. Figure 12 : Powe r D is si pat io n Der r at ing Cur v e.
L4964
9/13
APPLI CATION INFORMATI ON
CHOOSING THE INDUCTOR AND CAPACITOR
The input and output capacitors of the L4964 must
hav e a low E SR and l ow induc tance at high cur rent
ripple.
Pr eferab ly, the indu ctor s hould b e a tor oidal type or
wound on a Moly-Permalloy nucleus.Saturation
mu st not occur at curren t leve ls be low 1.5 t imes t he
current limiter level. MPP nuclei have very soft satu-
ration characteristics.
L = (Vi − Vo) V0
Vi f ∆IL, C = (Vi − Vo) V0
8L f2 ∆Vo
∆IL = Inductance cu rrent r ipp le
∆Vo = Output rip ple voltage
F ig ure 13 : Typic al Appli c at ion Cir cu it.
SUGGESTED INDUCTOR (L1)
Core Type No
Turns Wire
Gauge
(mmm)
Air
Gap
(mm)
Magnetics 58930 – A2MPP 43 1.0 –
Thomson GUP 20 x 16 x 7 50 0.8 0.7
Siemens EC 35/17/10
(B6633& – G0500 – X127) 40 2 x 0.8 –
VOGT 250 µH Toroidal Coil, Part Number
5730501800
Resistor Values for Standard Output Volt-
ages
V0R8 R7
12 V
15 V
18 V
4.7 kΩ
4.7 kΩ
4.7 kΩ
6.2 kΩ
9.1 kΩ
12 kΩ
L 4964
C7, C8 : EKR (ROE)
Figure 14 : P.C. Bo ar d and Com ponent La yo ut of the Cir c uit of F ig . 1 3 (1 :1 sc al e)
L4964
10/13
Multiwatt15 H (Short Leads)
A
C
B
E
L5
L7
L1L2
F
G1
G
H2
L4
L3
S1
S
H1
Diam 1
MW15HME
V
V
V V
V
H2
N
R1 P
R
R
DIM. mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 5 0.197
B 2.65 0.104
C 1.6 0.063
E 0.49 0.55 0.019 0.022
F 0.66 0.75 0.026 0.030
G 1.02 1.27 1.52 0.040 0.050 0.060
G1 17.53 17.78 18.03 0.690 0.700 18.030
H1 19.6 20.2 0.772 0.795
H2 19.6 20.2 0.772 0.795
L1 17.8 18 18.2 0.701 0.709 0.717
L2 2.3 2.5 2.8 0.091 0.098 0.110
L3 17.25 17.5 17.75 0.679 0.689 0.699
L4 10.3 10.7 10.9 0.406 0.421 0.429
L5 2.7 3 3.3 0.106 0.118 0.130
L7 2.65 2.9 0.104 0.114
R 1.5 0.059
S 1.9 2.6 0.075 0.102
S1 1.9 2.6 0.075 0.102
Dia1 3.65 3.85 0.144 0.152
OUTLINE AND
MECHANICAL DATA
MUL15V.TBL
L4964
11/13
Multiwatt15 V
DIM. mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 5 0.197
B 2.65 0.104
C 1.6 0.063
D 1 0.039
E 0.49 0.55 0.019 0.022
F 0.66 0.75 0.026 0.030
G 1.02 1.27 1.52 0.040 0.050 0.060
G1 17.53 17.78 18.03 0.690 0.700 0.710
H1 19.6 0.772
H2 20.2 0.795
L 21.9 22.2 22.5 0.862 0.874 0.886
L1 21.7 22.1 22.5 0.854 0.870 0.886
L2 17.65 18.1 0.695 0.713
L3 17.25 17.5 17.75 0.679 0.689 0.699
L4 10.3 10.7 10.9 0.406 0.421 0.429
L7 2.65 2.9 0.104 0.114
M 4.25 4.55 4.85 0.167 0.179 0.191
M1 4.63 5.08 5.53 0.182 0.200 0.218
S 1.9 2.6 0.075 0.102
S1 1.9 2.6 0.075 0.102
Dia1 3.65 3.85 0.144 0.152
OUTLINE AND
MECHANICAL DATA
MUL15H.TBL
L4964
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croelectronics products are not authorized for use as critical components in life support devices or systems without express written
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L4964
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