UNISONIC TECHNOLOGIES CO., LTD
LR478
LINEAR INTEGRATED CIRCUIT
www.unisonic.com.tw
1 of 8
Copyright 2005 Unisonic Technologies Co., LTD
QW-R112-001,B
REGULATOR+RESET IC
DESCRIPTION
The UTC
LR478
developed for use in CD-ROM drives,
combines a 3V regulator adapted to low power consumption with
a much-sought reset function (regulator input monitoring),with
internal delay circuit, set to detect 4.2V.
FEATURES
*Large Output Current: 300mA (max.)
*High Ripple Rejection Rate: 80dB(typ.)
*Internal Thermal Shutdown Circuit
*Internal Current Limiting Circuit
*Easy Set Delay Time from Voltage Detection to Reset Release
SOP-8
*Pb-free plating product number: LR478L
ORDERING INFORMATION
Order Number
Normal
Lead Free Plating
Package Packing
LR478-xx-S08-R LR478L-xx-S08-R SOP-8
Tape
Reel
LR478-xx-S08-T LR478L-xx-S08-T SOP-8 Tube
Note: xx: Output Voltage, refer to Rank List as below.
OUTPUT DETECTION VOLTAGE RANK LIST
PART NUMBER
REGULATOR OUTPUT VOLTAGE (V)
DETECTION VOLTAGE (V)
LR478-3.4V 3.400.05 4.200.09
LR478-3.3V 3.300.05 4.200.09
LR478-2.5V 2.500.05 4.200.09
LR478
LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD
2 of 8
www.unisonic.com.tw
QW-R112-001,B
PIN CONFIGURATION
8
7
6
5
1
2
3
4
N.C
RESET
CONT
V
IN
V
OUT
N.C
GND
Cd
PIN DESCRIPTION
PIN NO.
PIN NAME
FUNCTIONS
EQUIVALENT CIRCUIT DIAGRAM
1 N.C
2
RESET
Input voltage detection output
Input voltage detection output pin
RESET pin logic
RESET
V
IN
<V
S
L
V
IN
>V
S
H
RESET
3 CONT
Output voltage on/off-control pin
V
CONT
Output
L OFF
H ON
Connect cont-terminal with V
IN
when it
is not used.
CONT
300K
400K
4 V
IN
Voltage supply input pin
5 V
OUT
Regulator Output pin
6 N.C
7 GND
GND
pin
8 Cd
Delay time capacitor pin
RESET pin output delay time can be
set by the capacitance connected to
the Cd pin.
t
PLH
=100000.C
t
PLH
: transmission delay time[s]
C: capacitor value [F]
+
-
V
OUT
Cd
LR478
LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD
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www.unisonic.com.tw
QW-R112-001,B
BLACK DIAGRAM
RESET
CONT
V
IN
V
OUT
GND
Cd
Thermal
Protect
3
4
5
2
7
8
+
-
+
-
+
-
+
-
LR478
LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD
4 of 8
www.unisonic.com.tw
QW-R112-001,B
ABSOLUTE MAXIMUM RATINGS
PARAMETER SYMBOL
RATINGS
UNIT
Supply Voltage
V
IN
-0.3 ~ +10
V
Output Current
I
OUT
400 mA
Power Dissipation(note3)
P
D
700
mW
Junction Temperature
T
J
+125
C
Operating Temperature
T
OPR
-20 ~ +85
C
Storage Temperature
T
STG
-40~+150
C
Note 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
2. The device is guaranteed to meet performance specification within 0 ~ +70
operating temperature range
and assured by design from 20 ~ +85.
RECOMMENDED OPERATION CONDITIONS
PARAMETER SYMBOL
RATINGS
UNIT
Operating Voltage
V
OPR
0 ~ 10
V
Output Current
I
OUT
0 ~ 300
mA
ELECTRICAL CHARACTERISTICS
(V
CONT
=1.6V, Ta=25
C, unless otherwise specified )
PARAMETER SYMBOL
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
No-load Input Current 1
I
Q
1 V
IN
=5V, I
OUT
=0mA
3
8
mA
No-load Input Current 2
I
Q
2 V
IN
=4V, I
OUT
=0mA
4 mA
Input Current (OFF)
I
Q
3 V
IN
=5V, V
CONT
=0.4V
250 A
Regulator
Output Voltage
V
OUT
V
IN
=5V, I
OUT
=30mA
3.33 3.40 3.47
V
Input-Output Different Voltage
V
I/O(DIFF)
V
IN
=3.2V, I
OUT
=150mA
0.15
0.3
V
Line Regulation
V
OUT
V
IN
=4.4~5.5V, I
OUT
=30mA
10
20
mV
Load Regulation
V
OUT
V
IN
=5V, I
OUT
=0~300mA
20
120
mV
V
OUT
Temperature Coefficient
V
OUT
/T V
IN
=5V, I
OUT
=30mA, T
J
= -20~85
C 100
ppm/
C
Ripple Rejection
RR
V
IN
=5V, I
OUT
=30mA, f=120Hz
V
RIPPLE
=1V
P-P
50 80 dB
Output Noise Voltage
V
IN
V
IN
=5V, I
OUT
=30mA, f=20~80kHz
40
120 Vrms
CONT Terminal Current
I
CONT
V
CONT
=1.6V
5
10
A
High Threshold Voltage
V
THR(H)
1.6
V
IN
+0.3
V
Low Threshold Voltage
V
THR(L)
-0.3
0.4
V
Reset
Detection Voltage
VS
V
IN
= V
THR(H)
V
THR(L)
4.11 4.20 4.29
V
Vs Temperature Coefficient
V
S
/T T
J
= -20~85
C
100
ppm/
C
Hysteresis Voltage
V
HYS
V
IN
= V
THR(H)
V
THR(L)
V
THR(H)
100
200
mV
Low-Level Output Voltage
V
OL
V
IN
=3.9V, R
L
=4.7K
100
200
mV
Output Leakage Current
I
LEAK
V
IN
=5V
0.1
A
Output Current 1
I
OUT
1 V
IN
=3.9V, R
L
=0 5
mA
Output Current 2
I
OUT
2 V
IN
=3.9V, R
L
=0, Ta= -20~85
C 3
mA
"H" Transmission Delay Time
t
PLH
Cd
=0.0F
30 90 s
Reset Delay Time
t
PLH
1 V
IN
=4V5V, Cd =0.1F
5
10
20
ms
"L" Transmission Delay Time
t
PLH
30 90 s
Threshold Operating Voltage
V
THR(OPR)
V
oL
=0.4V
0.65
0.85
V
LR478
LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD
5 of 8
www.unisonic.com.tw
QW-R112-001,B
TEST CIRCUIT
A
CONT
+
V
OUT
Cd
4
2
UTC LR478
5
8
A
V
3
7
6
RESET
GND
V
IN
1F
47F
0.1F
4.7k
TYPICAL APPLICATION CIRCUIT
CONT
+
V
OUT
Cd
4
2
UTC LR478
5
8
3
7
6
RESET
GND
V
IN
1F
47F
0.1F
4.7k
C
OUT
Note: External output-capacitor(C
OUT
) for stability is necessary due to without internally compensated.
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