Ordering number : ENA0498
LA5779MP
Monolithic Linear IC
Separately-excited Step-down
Switching Regulator
(Variable Type)
Overview
The LA5779MP is a Separately-excited step-down switching regulator (variable type).
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Functions
•
High efficiency.
•
Six external parts.
•
Time-base generator (160kHz) incorporated.
•
Current limiter incorporated.
•
Thermal shutdown circuit incorporated.
•
ON/OFF function.
Specifications
Absolute
Maximum Ratings
at Ta = 25°C
Parameter
Maximum Input voltage
Maximum Output current
SW pin application reverse voltage
Allowable power dissipation
Operating temperature
Storage temperature
3
Symbol
VIN max
IO max
VSW
Pd max
Topr
Tstg
Conditions
Ratings
30
3
-1
Unit
V
A
V
W
°C
°C
Mounted on a substrate.*
3.9
-30 to +125
-40 to +150
* Specified substrate : 76.1×114.3×1.6mm : Copper foil ratio 60％ FR4
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
Recommended Operating Conditions
at Ta = 25°C
Parameter
Input voltage range
Symbol
VIN
Conditions
Ratings
4.5 to 28
Unit
V
Semiconductor Components Industries, LLC, 2013
August, 2013
N1306 MS PC 20060411-S00008 No.A0498-1/4
LA5779MP
Electrical Characteristics
at Ta
=
25°C, VO = 3.3V
Parameter
Reference voltage
Efficiency
Switching frequency
Switching frequency when
short-circuit protection is active
Line regulation
Load regulation
Output voltage temperature
coefficient
Ripple attenuation factor
Output leak current
Current limiter operating voltage
Operating current
Standby current
ENA pin LOW voltage range
ENA pin HIGH voltage range
Thermal shutdown operating
temperature
Thermal shutdown Hysteresis
width
* Design target value: No measurement made.
ΔTSD
Designed target value. *
15
°C
RREJ
IOleak
IS
IVIN
ISTBY
VENAL
VENAH
TSD
Designed target value. *
2.4
165
f = 100 to 120Hz
VIN = 15V, SWOUT = -0.4V
VIN = 15V
VIN = 15V
VIN = 15V, ENA = 5V
3.1
5.6
50
100
0.6
VIN
45
50
dB
μA
A
mA
μA
V
V
°C
ΔV
OLINE
ΔV
OLOAD
ΔV
O/ΔTa
VIN = 8 to 20V, IO = 1.0A
VIN = 15V, IO = 0.5 to 1.5A
Designed target value. *
40
10
±0.5
100
30
mV
mV
mV/°C
Symbol
VOS
η
f
fshort
Conditions
min
VIN = 15V, IO = 1.0A
VIN = 15V, IO = 1.0A, Set VO = 5V
VIN = 15V, IO = 1.0A
VIN = 15V, VOS = 0V
128
15
1.20
Ratings
typ
1.23
84
160
30
192
45
max
1.26
V
%
kHz
kHz
Unit
Package Dimensions
unit : mm (typ)
3275
4.5
Pd max - Ta
1.2
10.0
4.5
1.3
Allowable power dissipation, Pd max - W
4.0
3.90
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
-30 -20
Specified sbstrate: 76.1×114.3×1.6mm
3
Copper foil ratio 60% FR4
(8.8)
9.9
(1.6)
1.7
0.9
0.4
4.5
1.5
0.2
2.7
1
5
SANYO : SMP5
0
20
40
60
80
100
120
140
160
Ambient temperature, Ta -
°C
MSG06072
Pin Assignment
(1) VIN (2) SWOUT
(3) GND
(4) VOS
(5) ENA
No.A0498-2/4
LA5779MP
Description of Functional Settings
Calculation equation to set the output voltage
This IC controls the switching output so that the VOS pin voltage becomes 1.23V (typ).
The equation to set the output voltage is as follows:
R2
VO = 1+
×
1.23V(typ)
R1
The VOS pin has the inrush current of 1μA (typ). Therefore, the error becomes larger when R1 and R2 resistance
values are large.
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of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at
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application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental
damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual
performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical
experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use
as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in
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any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors
harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or
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PS No.A0498-4/4
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