Ordering number : ENA0719
Monolithic Linear IC
LA5772
Overview
Separately-excited Step-down
Switching Regulator (5V)
The LA5771 is a separately-excited step-down switching regulator (5V).
Features
•
High efficiency
•
Four external parts
•
Time-base generator (160kHz) incorporated
•
Current limiter incorporated
•
Thermal shutdown circuit incorporated
•
Soft start circuit incorporated
Specifications
Absolute Maximum Ratings
at Ta = 25°C
Parameter
Input voltage
Output current
SW pin application reverse voltage
Allowable power dissipation
Symbol
VIN max
IO max
Vsw
Pd max1
Pd max2
Operating temperature
Storage temperature
Topr
Tstg
No heat sink
Infinite heat sink
Conditions
Ratings
34
3
-1
1.75
7.5
-30 to +125
-40 to +150
Unit
V
A
V
W
W
°C
°C
Recommended Operating Conditions
at Ta = 25°C
Parameter
Input voltage range
VIN
Symbol
Conditions
Ratings
7 to 32
Unit
V
Any and all SANYO Semiconductor Co.,Ltd. products described or contained herein are, with regard to
"standard application", intended for the use as general electronics equipment (home appliances, AV equipment,
communication device, office equipment, industrial equipment etc.). The products mentioned herein shall not be
intended for use for any "special application" (medical equipment whose purpose is to sustain life, aerospace
instrument, nuclear control device, burning appliances, transportation machine, traffic signal system, safety
equipment etc.) that shall require extremely high level of reliability and can directly threaten human lives in case
of failure or malfunction of the product or may cause harm to human bodies, nor shall they grant any guarantee
thereof. If you should intend to use our products for applications outside the standard applications of our
customer who is considering such use and/or outside the scope of our intended standard applications, please
consult with us prior to the intended use. If there is no consultation or inquiry before the intended use, our
customer shall be solely responsible for the use.
Specifications of any and all SANYO Semiconductor Co.,Ltd. products described or contained herein stipulate
the performance, characteristics, and functions of the described products in the independent state, and are not
guarantees of the performance, characteristics, and functions of the described products as mounted in the
customer
'
s products or equipment. To verify symptoms and states that cannot be evaluated in an independent
device, the customer should always evaluate and test devices mounted in the customer
'
s products or
equipment.
30707 20070214-S00007 No.A0719-1/5
LA5772
Electrical Characteristics
at Ta = 25°C
Parameter
Output voltage
Efficiency
Switching frequency
Line regulation
Load regulation
Output voltage temperature coefficient
Ripple attenuation factor
Current limiter operating voltage
Thermal shutdown operating temperature
Thermal shutdown hysteresis width
VO
η
f
∆VOLINE
∆VOLOAD
∆VO/∆Ta
RREJ
IS
TSD
∆TSD
F=100 to 120Hz
VIN=15V
Designed target value*
Designed target value*
3.1
165
15
Symbol
Conditions
min
VIN=15V, IO=1.0A
VIN=15V, IO=1.0A
VIN=15V, IO=1.0A
VIN=8 to 20V, IO=1.0A
VIN=15V, IO=0.5 to 1.5A
120
4.80
Ratings
typ
5.00
84
160
40
10
±0.5
45
200
100
30
max
5.20
V
%
kHz
mV
mV
mV/°C
dB
A
°C
°C
Unit
* Designed target value: No measurement made.
Package Dimensions
unit : mm (typ)
3079C
10.0
Pd max -- Ta
3.6
2.7
10.4max
10.0
4.5
1.3
Allowable power dissipation, Pd max -- W
8.0
7.5
100×100×1.5mm
3
Infinite heat sink
θjc=5°C
15.0
6.0
5.6
50×50×1.5mm
3
Al heat
sink
mounting
torque
39N⋅cm
silicone
grease
applied
40
60
80
100
120
140
160
MSG07021
(8.8)
17.8
21.3
23.0
4.0
3.3
2.0
1.75
30×30×1.5mm
3
No heat sink
0.9
2.7
1
5
0.8
0.45
4.5
8.4
(1.6)
1.7
0
-30 -20
0
20
Ambient temperature, Ta --
°C
SANYO : 220-5H
Pin Assignment
(1)VIN (2)SWOUT (3)GND (4)VOS (5)SS
No.A0719-2/5
LA5772
Block Diagram
VIN 1
2 SWOUT
Reg.
OCP
OSC
Reset
Drive
Comp.
TSD
4 VOS
Amp.
VREF
5 SS
3 GND
Application Circuit Example
L1
68µH
VIN
SWOUT
LA5772
C1
220µF
/35V
D1
SBD
C2
1000µF
/6.3V
R2
R1
VOS
SS
C3
1µF
/50V
GND
Notes: C3 is for the soft start function. Delete C3 and keep the SS pin open when the soft function is not necessary.
No.A0719-3/5
LA5772
Description of Functional Settings
1.Start delay function
The SS pin has the internally-connected 22µA (typ) constant-current supply. When the voltage of SS pin exceeds the
threshold voltage, the regulator starts operation. As the threshold is 0.62V(typ), the start delay time can be calculated
as follows:
ex. For setting at 1µF
Td =
C
×
V 1µ
×
0.62
=
=
28.2 msec
22µ
i
1.5V
2.Soft start function
The internal PWM waveform has the voltage value as shown in the right.
If down-conversion from the voltage of VIN=20V to 5V output is to be made,
for example, the PWM-ON duty has the value as shown below.
VOUT +VF
PWMduty =
= 27%
VIN - Vsat + VF
0.62V
PWM wave
(Note that calculation is made with Vsat=1V and VF=0.2V)
The output voltage of error amplifier, which is 5V, is the value with PWM=27%, as calculated in the above equation,
so that this voltage is determined as follows:
Ver = (
∆
VPWM)
×
PWMduty + VPWML = 0.88V
×
0.27 + 0.62V=0.86V
(∆VPWM is the PWM amplitude value or 0.88V(typ) while VPWML is the lower limit voltage of PWM
waveform or 0.62V(typ))
SS pin and error amplifier output voltages are designed to prefer the lower voltages, so that VOUT will reach the
designed regulation voltage in timing when the SS pin voltage exceeds the error amplifier output. Therefore, the soft
strt time is calculated as follows:
Tss =
C
× ∆VPWM ×
PWMduty C
×
0.88
×
PWMduty
=
22µA
i
1µ
×
0.88V
×
0.27
= 10.8msec
22µA
For the set conditions of C=1µF and PWMduty=27%:
Tss =
No.A0719-4/5
LA5772
Timing Chart
VIN
SWOUT
VOUT
Td
Tss
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products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition
ranges, or other parameters) listed in products specifications of any and all SANYO Semiconductor Co.,Ltd.
products described or contained herein.
SANYO Semiconductor Co.,Ltd. strives to supply high-quality high-reliability products, however, any and all
semiconductor products fail or malfunction with some probability. It is possible that these probabilistic failures or
malfunction could give rise to accidents or events that could endanger human lives, trouble that could give rise
to smoke or fire, or accidents that could cause damage to other property. When designing equipment, adopt
safety measures so that these kinds of accidents or events cannot occur. Such measures include but are not
limited to protective circuits and error prevention circuits for safe design, redundant design, and structural
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No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
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Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification" for the
SANYO Semiconductor Co.,Ltd. product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed
for volume production.
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with regard to intellectual property rights or any other rights of SANYO Semiconductor Co.,Ltd. or any third
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This catalog provides information as of March, 2007. Specifications and information herein are subject
to change without notice.
PS No.A0719-5/5
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