Ordering number : ENA1843
Bi-CMOS IC
LV5857MX
Overview
Step-down Switching Regulator
LV5857MX is a 1ch step-down switching regulator. With built-in two 0.13Ω power MOSFET switch, it achieves high
output current and high efficiency. With low-heat resistance, miniature package MFP8 (200mil) with heat-sink is adopted.
Since it is Current mode control type, it has good load current response, and phase compensation is easy. With ON/OFF pin,
operating can be less than 60μA at stand-by mode. It has cycle-by-cycle over current protection for load devices. With
external capacitor, it achieves soft start.
Functions
•
3A 1ch step-down
•
Small package: MFP8 (200mil) with heat sink
•
High efficiency (93% IOUT = 1A, VIN = 12V, VO = 5V)
•
Standby mode
•
Over-current protection(Latch off method)
•
Thermal shutdown protection
•
Reference voltage: 0.672V
•
Fixed frequency: 340kHz
•
Soft start / Soft stop
Specifications
Maximum Ratings
at Ta = 25°C
Parameter
Maximum input VIN voltage
BOOT pin maximum voltage
SW pin maximum voltage
BOOT pin-SW pin maximum voltage
EN Maximum Voltage
FB, COMP, SS pin maximum voltage
Allowable power dissipation
Junction temperature
Operating temperature
Storage temperature
Symbol
VIN max
VBT max
VSW max
VBS-SW max
VEN max
Vfs max
Pd max
Tj max
Topr
Tstg
Mount on a specified board *
Conditions
Ratings
20
25
VIN max
7
20
7
2.05
150
-20 to 80
-40 to 150
Unit
V
V
V
V
V
V
W
°C
°C
°C
Specified substrate : 46.0mm
х
32.0mm
х
1.6mm glass epoxy substrate.
Note: Plan the maximum voltage while including coil and surge voltages, so that the maximum voltage is not exceeded even for an instant.
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.
92910 SY 20100915-S00003 No.A1843-1/5
LV5857MX
Recommended Operating Conditions
at Ta = 25°C
Parameter
VIN pin voltage
BOOT pin voltage
SW pin voltage
BOOT pin-SW pin voltage
EN voltage
FB, COMP, SS pin voltage
VIN
VBT
VSW
VBS-SW
VEN
VFSO
Symbol
Conditions
Ratings
8 to 18
-0.3 to 23
-0.4 to VIN
6.5
18
6
Unit
V
V
V
V
V
V
Electrical Characteristics
at Ta
=
25°C, VIN = 12V, unless otherwise specified.
Parameter
IC current drain at standby
IC current drain in operation
Efficiency
Reference voltage
FB pin bias current
High-side ON resistance
Low-side ON resistance
Oscillation frequency
EN high-threshold voltage
Maximum ON DUTY
Minimum ON DUTY
SW Peak Current limit
Thermal shutdown temperature
Thermal shutdown temperature
hysteresis
Soft start current
Discharge On-Resistance
VIN UVLO lock voltage
VIN UVLO lock release voltage
ISS
VSWON
VUVLOL
VUVLOH
SS=0V
6
35
6.0
6.9
μA
Ω
V
V
Symbol
ICC1
ICC2
Effcy
Vref
Iref
RonH
RonL
fOSC
Venth
D max
D min
Icl1
Ttsd
Dtsd
VIN=12V, VOUT=5V, L=10μH
*Design guarantee *3
*Design guarantee *3
4
160
40
80
8
EN=0V
EN=5v, FB=1V
VIN=12V, IOUT=1A, Vo=5V, Design target *2
VIN=8V to 28V
FB=0.672V
BOOT=5V, IOUT=1A
-2%
Conditions
Ratings
min
typ
60
2.5
93
0.672
10
0.13
0.13
340
1.5
+2%
100
max
Unit
μA
mA
%
V
nA
Ω
Ω
kHz
V
%
%
A
°C
°C
*2: Reference value (not tested before shipment)
*2: Design guarantee (value guaranteed by design and not tested before shipment)
No.A1843-2/5
LV5857MX
Package Dimensions
unit : mm (typ)
3372
2.5
Pd max -- Ta
2.05
5.0
8
(3.4)
Allowable power dissipation, Pd max -- W
TOP VIEW
SIDE VIEW
BOTTOM VIEW
2.0
1.5
1.15
1.0
1
(0.65)
2
0.35
1.27
SIDE VIEW
0.15
0.43
(2.6)
4.4
6.0
0.5
1.7 MAX
(1.5)
0
-20
0
20
40
60
80
100
Ambient temperature, Ta --
∞C
0.05
SANYO : MFP8(200mil)
Pin Assignment
BOOT 1
VIN 2
SW 3
GND 4
Top view
8 SS
7 EN
6 COMP
5 FB
Block Diagram and Sample Application Circuit
BOOT (SW + Vreg.)
BOOT
VIN
+
UVLO
Current Sense
Amp.
Pre-Drive
1:N
Rb
SW
VOUT
FB
COMP
C4=OPEN
OSC
340kHz
-
+
Error
Amp.
-
+
PWM
comparator
Pre-Drive
GND
UVP
OVP
Current
Limit
EN
UVLO
TSD
Soft-Stop
-30%
+20%
C3
+
-
+
-
SS
EN
H : ON
L : OFF
Internal Stable
supply
Vref
0.672V
VIN
TSD
Internal
Regulator
Internal Regulator
(5V)
C1,C2,C5,C8,C9=Ceramic capacitor
No.A1843-3/5
LV5857MX
Pin Function
Pin No.
1
Pin name
BOOT
Function
Upper MOS transistor boot strap capacitance connection pin.
Connect the boot capacitance of about 0.1uF between SW pins.
To protect the SW pin’s absolute maximum rating , to ensure
stable
operation, and to eliminate noise , the boot capacitance serial
resistance (about 15Ω) Rb
proves effective.
Input Voltage Pin. Connect substantially large (10uF 1 piece or 2
parallel or more) capacitance between this pin and GND.
Power Switch pin.
Connect the output LC filter.
Connect the above capacitance between this pin and BOOT pin.
The discharge transistor for a Soft-Stop is connected with this
terminal (typcal 35Ω). It turns it on by either EN=L, UVLO or a
thermal shutdown.
Equivalent circuit
VIN
BOOT
2
3
VIN
SW
High side MOS
SW
Discharge
Low side MOS
4
5
GND
FB
Ground pin.
Feedback pin.
Set the output voltage by means of split resistor in the section of
the output voltage
VOUT-FB-GND. VOUT setting is made as calculated below.
VOUT = Vref
×
{ 1 +
(R1 + R10)
}
R3
Vref = 0.672V
Example: 3.3V output voltage
(See, Block Diagram and Application example)
VOUT = 0.672
×
{ 1 +
(22k + 3.9k)
}
10k
VIN
8
SS
=3.353V
Soft start pin.
Sets the soft start time by means of the built-in 6μA source
voltage and external soft start capacity. The soft start capacity C6
can be set as follows:
Tss
C6 = 6μA
×
Vref
Where, Tss is the soft start time and Vref is the reference
voltage.
Example:1.7ms soft start time achieved
1.7ms
C6 = 6μA
×
0.672V = 0.015μF
SS
VREF
0.672V
FB
6
COMP
Phase compensation pin.
Connects with the phase compensation external capacitance and
resistance of DC/DC converter close loop.
VIN
COMP
7
EN
Enable pin.
Converter enabled when set to the HIGH voltage and disabled
when LOW voltage or OPEN state.
VIN
EN
2pF
No.A1843-4/5
LV5857MX
SANYO Semiconductor Co.,Ltd. assumes no responsibility for equipment failures that result from using
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
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limited to protective circuits and error prevention circuits for safe design, redundant design, and structural
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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
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Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed
for volume production.
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above.
This catalog provides information as of September, 2010. Specifications and information herein are subject
to change without notice.
PS No.A1843-5/5
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