Ordering number : ENA1376
Bi-CMOS LSI
LV5749V
Overview
1-channel Step-down Switching
Regulator
The LV5749V is a 1-channel step-down switching regulator.
Functions
•
1 channel step-down switching regulator controller.
•
Load-independent soft start circuit.
•
ON/OFF function.
•
Built-in pulse-by-pulse OCP circuit. It is detected by using ON resistance of an external MOS.
•
Synchronous rectification.
•
Current mode control.
•
Synchronous drive by external signal.
Specifications
Absolute Maximum Ratings
at Ta = 25°C
Parameter
supply voltage
Allowable Power dissipation
Operating temperature
Storage temperature
Symbol
VIN max
Pd max
Topr
Tstg
Mounted on a specified board. *
Conditions
Ratings
45
0.74
-40 to +85
-55 to +150
Unit
V
W
°C
°C
* : When mounted on the specified printed circuit board (114.3 × 76.1 × 1.6mm), glass epoxy
Recommended Operating Range
at Ta = 25°C
Parameter
Supply voltage range
Error amplifier input voltage
VIN
Symbol
Conditions
Ratings
8.5 to 42
0 to 1.6
Unit
V
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.
D2408 MS PC 20081208-S00002 No.A1376-1/6
LV5749V
Electrical Characteristics
at Ta
=
25°C, VIN = 12V
Parameter
Reference voltage block
Internal reference voltage
5V power supply
Vref
VDD
Including offset of E/A
IOUT = 0 to 5mA
0.654
4.7
0.67
5.2
0.686
5.7
V
V
Symbol
Conditions
min
Ratings
typ
max
Unit
Triangular waveform oscillator block
Oscillation frequency
Frequency variation
ON/OFF circuit block
IC start-up voltage
IC off voltage
Soft start circuit block
Soft start source current
Soft start sink current
UVLO circuit block
UVLO lock release voltage
UVLO hysteresis
OCP circuit block
OCP charge current
Error amplifier
Input bias current
Error amplifier transconductance
Sink output current
Source output current
Current detection amplifier gain
over current limiter circuit block
Reference current 1
Reference current 2
Over current detection comparator
offset voltage
Over current detection comparator
common mode input range
PWM comparator
Input threshold voltage
(fosc = 125kHz)
Maximum ON duty
Output block
Output stage ON resistance
(the upper side)
Output stage ON resistance
(the under side)
Output stage ON current
(the upper side)
Output stage ON current
(the under side)
The whole device
Standby current
Mean consumption current
ICCS
ICCA
EN
<
1V
EN
>
3.5V
3
10
μA
mA
IONL
240
mA
IONH
240
mA
RONL
5
Ω
RONH
5
Ω
Vt max
Vt0
DMAX
Duty cycle = DMAX
Duty cycle = 0%
0.9
0.4
80
1.0
0.5
85
1.1
0.6
90
V
V
%
VIN-0.45
VIN
V
ILIM1
ILIM2
VLIM OFS
MODE = L (GND)
MODE = H (VIN)
-10%
-10%
-5
18.5
37.0
+10%
+10%
+5
μA
μA
mA
IEA IN
GEA
IEA OSK
IEA OSC
GISNS
FB = 1.0V
FB = 0V
1000
1400
-100
100
1.5
100
1800
nA
μA/V
μA
μA
IOCP
5
μA
VUVLO
VUVLO H
7.5
8.0
0.7
8.5
V
V
ISS SC
ISS SK
EN
>
3.5V
EN
<
1V
4
5
2
6
μA
mA
VEN on
VEN off
2.5
1.0
3.0
1.2
3.5
1.4
V
V
FOSC
FOSC DV
RT = 220kΩ
VIN = 8.5 to 42V
110
125
1
140
kHz
%
No.A1376-2/6
LV5749V
Package Dimensions
unit : mm (typ)
3178B
5.2
16
9
4.4
6.4
1
0.65
(0.33)
8
0.15
0.22
1.5max
SANYO : SSOP16(225mil)
Pin Assignment
0.1
(1.3)
FB 1
COMP 2
EN 3
RT 4
0.5
16 SS
15 ILIM
14 VIN
13 OCP
LV5749V
SYNC 5
SW 6
CBOOT 7
HDRV 8
12 MODE
11 GND
10 VDD
9 LDRV
Top view
No.A1376-3/6
LV5749V
Block Diagram
VIN 14
MODE 12
5μA
OCP 13
1.25V
+
-
OCP Comp1
-
+
OCP Comp2
VCC
OSP
LOGIC
5V
REGULATOR
REFERENCE
VOLTAGE
UVLO
ILIM 15
MODE L 18.5μA
MODE H 37μA
5μA
SD
SS 16
FB 1
COMP 2
0.67V
+
+
-
S Q
R
+
-
Current
Amp
DMAX = 90%
1.0V
0.5V
CONTROL
Logic
5V
10 VDD
9 LDRV
shut down(SD)
4 5
RT SYNC
3
EN
11 GND
7 CBOOT
8 HDRV
6 SW
-
+
PWM Comp
SAW WAVE
OSCILLATOR
Err
Amp
Pin Function
Pin No.
14
Pin name
VIN
Power supply pin.
This pin is monitored by UVLO function. When the voltage of this pin becomes 7.5V or more by UVLO function, The IC starts
and the soft start function operates.
11
10
7
GND
VDD
CBOOT
Ground pin. Each reference voltage is based on the voltage of the ground pin.
Power supply pin for an external the lower MOS-FET gate drive.
Bootstrap capacity connection pin. This pin becomes a GATE drive power supply of an external NchMOSFET.
Connect a bypath capacitor between CBOOT and SW.
6
5
9
8
1
SW
SYNC
LDRV
HDRV
FB
Pin to connect with switching node. The source of NchMOSFET connects to this pin.
External synchronous signal input pin.
An external the lower MOSFET gate drive pin.
An external the upper MOSFET gate drive pin.
Error amplifier reverse input pin.
By operating the converter, the voltage of this pin becomes 0.67V.
The voltage in which the output voltage is divided by an external resistance is applied to this pin.
2
COMP
Error amplifier output pin.
Connect a phase compensation circuit between this pin and GND.
16
SS
Pin to connect a capacitor for soft start. A capacitor for soft start is charged by using the voltage of about 5μA.
This pin ends the soft start period by using the voltage of about 1.1V and the frequency fold back function becomes
active.
15
ILIM
Reference current pin for current detection.
The sink current of about 18.5μA flows to this pin when Low level (GND) is set to the MODE pin.
Also, the sink current of about 37μA flows to this pin when High level (VIN) is set to the MODE pin.
When a resistance is connected between this pin and VIN outside and the voltage applied to the SW pin is lower than the
voltage of the terminal side of the resistance, the upper NchMOSFET is off by operating the current limiter comparator. This
operation is reset with respect to each PWM pulse.
3
13
EN
OCP
ON/OFF pin.
Pin to set the time of the timer (during double the over current detection point)
Connect a capacitor between this pin and GND. OCP charge current : 5μA
4
12
RT
MODE
Pin to set the oscillation frequency. Connect a resistance between this pin and GND.
Pin to switch the over current detection point. Set by the low level (GND) of the ILIM pin.
Set by the high level (VIN) of the OCP pin.
When this MODE pin is set to the high level and the point of the over current detection is set by using the ILIM pin is exceeded,
the value becomes double the original value.
Also, when the MODE pin is set to the low level, the point of the over current detection remains an original value.
Description
No.A1376-4/6
LV5749V
Timing Chart
When the MODE pin is set to the high level and the point of the over current detection is set by using the ILIM pin is
exceeded, the value becomes double the original value.
Also, when the MODE pin is set to the low level, the point of over current detection remains an original value.
Timing chart of the over current detection point switching is as below.
t
1.25V
OCP
0V
over current detection point during High MODE
current limit
×
2A
For example 6A
current limit
×
1A
For example 3A
over current detection point during Low MODE
Load Current
Setting Chart
1. Output voltage setting
• Setting of the output voltage VOUT is as follows.
R4
R4
VOUT = 1 + R3
×
VREF = 1 + R3
×
0.67(typ) [V]
2. Soft Start setting
• Setting of capacitor C5 is as follows.
Iss
×
Tss
5μ
×
Tss
C5 = V
= 0.67 [F]
REF
Iss : Charge current value.
Tss : Soft Start time
3. OCP Timer setting
• Setting of OCP timer capacitor C11 is as follows.
5μ
×
Tocp
Iocp
×
Tocp
[F]
C11 = Vocp comp1 =
1.3
Iocp : Charge current value.
Tocp : OCP time
4. Current limiter setting
• Setting of the current limiter set resistance R5 is as follows.
R5 =
Rdson
×
IL max
Rdson
×Iout
=
[Ω]
Iilim
18.5μ
Iilim : ILIM current value.
IL : inductance current value
Rdson : ON resistance value between Q1 drain-souces.
No.A1376-5/6
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