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Электронный компонент: G5121TB1U

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Ver: 1.1
Nov 17, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
1
G5121
Global Mixed-mode Technology Inc.
Fixed Frequency White LED Step-Up Converter
Features
Inherently Matched LED Current
High Efficiency: 87%
Drives Up to Five LEDs from 2.5V Supply
24V Internal Power Switch
Fast 1MHz Switching Frequency
Uses Tiny 1mm Tall Inductors
Requires Only 1F Output Capacitors
19.5V Over Voltage Protection
SOT-23-6 Package
Applications
White LED Backlight Display for PDA
Pocket PC
Smart Phones
Handheld Devices
Cellular Phones
General Description
The G5121 is a step-up DC/DC converter specifically
designed to drive up to 5 series white LEDs with con-
stant current. Series connection of the LEDs provides
identical LED currents resulting in uniform brightness
and eliminates the need for ballast resistors. The
G5121 switches at 1MHz, allowing the use of tiny ex-
ternal components. A low 0.254V feedback voltage
minimizes power loss in the current setting resistor for
high efficiency. The OVP pin monitors the output volt-
age and turns off the converter whenever the LEDs
are open.
The G5121 is available in low profile SOT-23-6 pack-
age.
Ordering Information
ORDER
NUMBER
MARKING
TEMP.
RANGE
PACKAGE
(Pb free)
G5121TB1U
5121x
-40C ~ +85C
SOT-23-6
Note:
TB : SOT23-6
U: Tape & Reel
Pin Configuration
Typical Application Circuit
VCC
SHDN
SOT-23-6
G5121
6
4
1
SW
2
3
GND
FB
5 OVP
VCC
SW
SHDN
FB
GND
G5121
L1
V
IN
2.7V to 4.2V
D1
OVP
5 LEDs
PWM Dimming
Waveform
R
S
C1
4.7F/6.3V
4.7H
C2
1F/25V
C1:TAIYO YUDEN, JMK212BJ475KD
C2:TAIYO YUDEN, TMK316BJ105KD
VCC
SHDN
SOT-23-6
G5121
6
4
1
SW
2
3
GND
FB
5 OVP
VCC
SW
SHDN
FB
GND
G5121
L1
V
IN
2.7V to 4.2V
D1
OVP
5 LEDs
PWM Dimming
Waveform
R
S
C1
4.7F/6.3V
4.7H
C2
1F/25V
VCC
SHDN
SOT-23-6
G5121
6
4
1
SW
2
3
GND
FB
5 OVP
VCC
SW
SHDN
FB
GND
G5121
L1
V
IN
2.7V to 4.2V
D1
OVP
5 LEDs
PWM Dimming
Waveform
R
S
C1
4.7F/6.3V
4.7H
C2
1F/25V
C1:TAIYO YUDEN, JMK212BJ475KD
C2:TAIYO YUDEN, TMK316BJ105KD
Ver: 1.1
Nov 17, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
2
G5121
Global Mixed-mode Technology Inc.
Absolute Maximum Ratings
VCC,
SHDN
to GND...............................-0.3V to +7V
FB to GND.................................................-0.3V to VCC
SW, OVP to GND................................-0.3V to +24V
Operating Temperature.........................-40C to 85C
Junction Temperature..........................................125C
Storage Temperature..........................-65C to 150C
Reflow Temperature (soldering, 10sec)............260C
ESD Rating (Human Body Model).......................2kV
Stress beyond those listed under "Absolute Maximum Rating" may cause permanent damage to the device.
Electrical Characteristics
(V
CC
=V
SHDN
=3.6V, T
A
=25C)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
2.5
---
6 V
Input Voltage UVLO
1.7 2.0 2.3 V
Over Voltage Protection Threshold
trigger
18.5
19.5 21 V
Over Voltage Protection Threshold
release
13.5
15
16.5
V
OVP Pin Input Current
V
ovp
= 16V
---
40 60 A
V
FB
= 0.3V
(no switching)
---
80 120 A
V
FB
= 0.2V
(switching)
---
---
2 mA
Quiescent Current
V
SHDN
= 0V
---
0.1 1 A
Initial
Accuracy
244 254 264 mV
FB Comparator Trip Point
Temperature Coefficient
---
100
---
ppm/C
Switching Frequency
V
FB
=
0.2V
0.8 1.0 1.2 MHz
Maximum Duty
85
---
---
%
Switch R
DS(ON)
I
SW
= 150mA
---
0.7 1.0
Switch Leakage Current
V
SW
= 20V
---
0.1 10 A
Switch Current Limit
500
600
700
mA
Soft Start Time
---
120
---
s
SHDN
Pin Voltage High
2
---
---
V
SHDN
Pin Voltage Low
---
---
0.8 V
Ver: 1.1
Nov 17, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
3
G5121
Global Mixed-mode Technology Inc.
Typical Performance Characteristics
(V
CC
= +3.6V, V
SHDN
= +3.6V, L=4.7H, T
A
=25
C, unless otherwise noted.)
Stability for Driving 5 WLEDs
Stability for Driving 4 WLEDs
Stability for Driving 3 WLEDs
Stability for Driving 2 WLEDs
Inrush Current for Driving 5 WLEDs
Inrush Current for Driving 4 WLEDs
Ver: 1.1
Nov 17, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
4
G5121
Global Mixed-mode Technology Inc.
Typical Performance Characteristics
(continued)
10
20
30
40
50
60
70
80
90
0
5
10
15
20
25
Load Current (mA)
E
f
f
i
ci
e
n
cy (
%
)
5LEDs, C
O
=1F
V
IN
=4.2V
V
IN
=2.7V
V
IN
=3.6V
10
20
30
40
50
60
70
80
90
0
5
10
15
20
25
Load Current (mA)
E
f
f
i
ci
e
n
cy (
%
)
V
IN
=4.2V
V
IN
=3.6V
V
IN
=2.7V
4LEDs, C
O
=1F
Efficiency vs. Load Current
Efficiency vs. Load Current
Inrush Current for Driving 3 WLEDs
Inrush Current for Driving 2 WLEDs
OVP Waveform
Dimming Control for Driving 4 WLEDs
Ver: 1.1
Nov 17, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
5
G5121
Global Mixed-mode Technology Inc.
Typical Performance Characteristics
(continued)
10
20
30
40
50
60
70
80
90
0
5
10
15
20
25
Load Current (mA)
E
f
fi
c
i
enc
y
(
%
)
V
IN
=3.6V
3LEDs, C
O
=1F
V
IN
=4.2V
V
IN
=2.7V
10
20
30
40
50
60
70
80
90
0
5
10
15
20
25
Load Current (mA)
Effici
en
cy
(
%
)
V
IN
=4.2V
V
IN
=3.6V
V
IN
=2.7V
2LEDs, C
O
=1F
0
10
20
30
40
50
60
70
80
90
100
110
120
130
2
2.5
3
3.5
4
4.5
5
5.5
6
Input Voltage (V)
IQ
_N
o
S
W
(
u
A)
0
10
20
30
40
50
60
70
80
90
100
-40
-20
0
20
40
60
80
100
Temperature (C)
IQ
_N
o
S
W
(
u
A)
0.7
0.75
0.8
0.85
0.9
0.95
1
2
2.5
3
3.5
4
4.5
5
5.5
6
Input Voltage (V)
F
r
eque
nc
y
(
M
H
z
)
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
1.1
-40
-20
0
20
40
60
80
100
Temperature (
C)
F
r
equen
c
y
(M
Hz
)
Efficiency vs. Load Current
Efficiency vs. Load Current
IQ_NoSW vs. Input Voltage
IQ_NoSW vs. Temperature
Frequency vs. Input Voltage
Frequency vs. Temperature