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Ordering number : ENA2178
LV5771QA
Bi-CMOS IC
Step-down Voltage Switching Regulator
http://onsemi.com
Overview
LV5771QA is a step-down voltage switching regulator.
Features and Functions
Wide Input dynamic range: 8V to 42V
Current mode type
Built-in pulse-by-pulse OCP cicuit: detects over current by using ON resistance of an external of an external MOS
external resistance for over current detection.
Over current protection: HICCUP MODE
Built-in output voltage correction circuit
Droops when frequency FOLD BACK is negative
Teermal shutdown
Fixed frewuency: 1MHz
Load-independent soft start circuit
Over voltage protection
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Supply voltage
VIN, SW
HDRV, CBOOT
Symbol
VIN max
Conditions
Ratings
Unit
45 V
45 V
52 V
LDRV
6V
Between CBOOT and SW,
Between CBOOT and HDRV
EN, ILIM
Between VIN and ILIM
VDD
SS, COMP, FB, SDIN
SNS_OCP, SNS_COM,
SNS_CS
Allowable Power dissipation
Pd max
Mounted on a specified board. *
6
VIN+0.3
1
6
VDD+0.3
7
0.65
V
V
V
V
V
V
W
Operating temperature
Storage temperature
Junction temperature
Topr
Tstg
Tj max
-40 to +85
-55 to +150
150
°C
°C
°C
* Specified board: 24.0mm × 15.0mm × 1.6mm, glass epoxy 2-layer board.
Caution 1) Absolute maximum ratings represent the values which cannot be exceeded for any length of time.
Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current,
high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details.
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.
ORDERING INFORMATION
See detailed ordering and shipping information on page 12 of this data sheet.
Semiconductor Components Industries, LLC, 2013
May, 2013
51513NKPC 20130401-S00002 No.A2178-1/12

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LV5771QA
Recommendation Operating Conditions at Ta = 25°C
Parameter
Supply voltage range
Error amplifier input voltage
Symbol
VIN
VFB
Conditions
Electrical Characteristics at Ta = 25°C, VIN = 12V
Parameter
Symbol
Conditions
Reference voltage block
5V power supply
Internal reference voltage
VDD
VREF
Triangular waveform oscillator block
Oscillation frequency1
Oscillation frequency2
FOSC1
FOSC2
Oscillation frequency3
FOSC3
Oscillation
Fold back sense voltage
VOSC_FB
Oscillation frequency after fold
back
FOSC_FB
Maximum ON duty
DMAX
ON/OFF circuit block
EN ON voltage
EN OFF voltage
VEN_ON
VEN_OFF
Soft Start circuit block
Soft start source current
Soft start sink current
Voltage to end the soft start
function
ISS_SC
ISS_SK
VSS_END
UVLO circuit block
UVLO lock release voltage
VUVLO
UVLO hysteresis
VUVLO_H
Error amplifier
Input bias current
IEA_IN
Error amplifier trans
conductance
GEA
Sink output current
IEA_OSK
Source output current
IEA_OSC
Over current limiter circuit block1
Over current detection
comparator 1 Offset voltage
VSNS_OCP
Over current limiter circuit block2
Reference current
ILIM
Over current detection
comparator 2 Offset voltage
VLIM_OFS
Over current detection
comparator 2 common mode
input voltage
Over voltage protection circuit block1
Over voltage detection voltage VSNS_OCP
Over voltage detection voltage VSNS_COM
Over voltage protection circuit block2
Over voltage detection voltage 2 VSDIN
IOUT = 0 to 5mA
Including offset of E/A
VIN = 12V (8V to 18V)
VIN = 24V (18V to 30V)
VIN = 36V (30V to 42V)
After power is supplied to SS, voltage is
detected FB
VIN = 8 to 42V
VIN = 8 to 42V
EN > 5V, SS = 0V
EN < 1V, VDD = 5V, SS = 1V
FB = 1.0V
FB = 0V
(R6 = 20mΩ)
Ratings
8 to 42
0 to 1.6
Unit
V
V
Ratings
Unit
min typ max
4.7
0.69
5.2 5.7 V
0.7
0.71
V
870 1000
1/2 ×
FOSC1
1/3 ×
FOSC1
0.5
100 150
75
1130
kHz
kHz
kHz
V
200 kHz
%
3.4 4.3 V
1.0 1.2
V
4 5 6 μA
2 mA
0.7 0.9 1.1 V
7.0
1000
43.5
7.4
0.6
1400
-100
100
46
7.8 V
V
100
1800
nA
μA/V
μA
μA
48.5 mV
-10%
-5
VIN-0.45
20
+10%
μA
+5 mV
VIN V
6.7 V
6.7 V
0.7 V
Continued on next page.
No.A2178-2/12

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Continued from preceding page.
Parameter
Output block
Output stage ON resistance
(upper side)
Output stage ON resistance
(lower side)
Output stage ON current
(upper side)
Output stage ON current
(lower side)
The whole device
Standby current
Mean consumption current
Symbol
RONH
RONL
IONH
IONL
ICCS
ICCA
LV5771QA
Conditions
EN < 1V
EN > 5V, No switching
Ratings
min typ max
5
5
240
240
Unit
Ω
Ω
mA
mA
100 μA
3 mA
Package Dimensions
unit : mm (typ)
3444
TOP VIEW
3.0
SIDE VIEW
BOTTOM VIEW
12
SIDE VIEW
(1.7)
16
21
0.5
(0.75)
0.25
VQFN16J(3.0X3.0)
Pd max – Ta
1.0 Specified board: 24.0×15.0×1.6mm3
glass epoxy board
(Two-layer substrate, 4-layer board)
0.8
0.65
0.6
0.4 0.42
0.34
0.2
0
--40 --20
0
20 40 60 80
Ambient temperature, Ta -- °C
100
No.A2178-3/12

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Pin Assignment
LV5771QA
16 15 14 13
SNS_COM 1
COMP 2
SDIN 3
LV5771QA
QFN16
12 ILIM
11 VIN
10 GND
EN 4
9 VDD
5678
Top view
Pin Function
No Pin Name
1 SNS_COM
2 COMP
3 SDIN
4 EN
5 CBOOT
6 HDRV
7 SW
8 LDRV
9 VDD
10 GND
11 VIN
12 ILIM
13 SS/HICCUP
14 SNS_CS
15 SNS_OCP
16 FB
Description
Pin to connect a current sense resister
Error amplifier output pin. Connect a phase compensation circuit between this pin and GND.
When voltage level of this pin is High, switchinf is turned off. When this pin turns Low, the capacitor connected between
SS/HICCUP and GND discharges voltage.
ON/OFF pin.
Bootstrap capacity connection pin. This pin becomes a GATE drive power supply of an external NchMOSFET. Connect a
bypath capacitor between CBOOT and SW.
An external the upper MOSFET gate drive pin.
Pin to connect with switching node. The source of NchMOSFET connects to this pin.
An external the lower MOSFET gate drive pin.
Power supply pin for an external the lower MOS-FET gate drive.
Ground pin. Each reference voltage is based on the voltage of the ground pin.
Power supply pin. This pin is monitored by UVLO function. When the voltage of this pin becomes 7.8V or more by UVLO
function, The IC starts and the soft start function operates.
Reference current pin for current detection. The sink current of about 20μA flows to this 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.
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.
Output voltage correction rate pin.
Pin to connect a current sense resister. Overcurrent protector limit function operates when the voltage of the both ends of
external sense resistance exceed 46mV. When you do not use this function, make sure to connect the pin of the external
sense resistance to GND.
Error amplifier reverse input pin. By operating the converter, the voltage of this pin becomes 0.7V. The voltage in which
the output voltage is divided by an external resistance is applied to this pin. Also, the oscillation frequency becomes
one-tenth when the voltage of this pin becomes 0.4V or less after soft start function.
No.A2178-4/12

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Block Diagram
LV5771QA
VIN
SNS_OCP
SNS_COM
SNS_CS
SDIN
ILIM
SS/HICCUP
FB
COMP
OVP Comp1
+
-
6.7V OVP Comp2
+
-
6.7V
46mV
- Amp
+
OCP Comp2
+
-
5V
REGULATOR
FB
REFERENCE
VOLTAGE
TSD
UVLO
SS/
HICCUP
20μA
5μA
SD
-
+
OCP Comp1 VIN +
-
+
Current
Amp
-
2V HICCUP Comp
SQ
R
OCP
1.1V
+
-
SS Comp
0.7V ++
-
FB
SD
Error
Amp
S
R
0.5V
Q SAW WAVE
OSCILLATOR
fosc forced
1/8
-
+
FFOLD
Amp
DMAX = 90%
+
-
1V
+
-
1V
PWM Comp
-
+
foce 1/2
foce 1/3
CONTROL
Logic
5V
shut down(SD)
Sample Application Circuit
EN
CBOOT
HDRV
SW
VDD
LDRV
GND
R5 C6 C1
R2
C5
C3
VIN ILIM
CBOOT
HDRV
EN LV5771QA SW
SS/HICCUP
LDRV
SDIN
COMP
FB
SNS_CS
SNS_OCP
SNS_COM
GND
VDD
C31
C2
Q
D1 Q
L
D2 C7 R16
C8 C12 C10
D3
R10
D4
R9
C11
C13 R8
No.A2178-5/12