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Global Mixed-mode Technology Inc.
G5103
Micro-power Step-Up DC/DC Converters in SOT-23-5
Features
Configurable Output Voltage Up to 16V 20A Quiescent Current <1A Shutdown Current <1A Shutdown Pin Current Supply Range from 2.5V to 6.5V Low VDS(on): 250mV (ISW=300mA) Tiny SOT-23-5 Package
General Description
The G5103 boost converter is designed for small/ medium size LCD panel of high bias voltage. Due to a typical 20A quiescent current and 2.5V~ 6.5V supply voltage range, it is suitable for battery powered portable applications. Such as PDAs and Handheld Computers. When the IC sets to shutdown mode, it only consumes less than 1A. Furthermore, the 350mA current limit, 500ns fixed minimum off-time and tiny SOT23-5 package facilitates the use of smaller inductor and other surface-mount components to minimize the PCB size in those space-conscious applications. To control the IC, no other external current is needed for the shutdown pin. It typically consumes less than 1A of full supply range.
Applications
STN/TFT LCD Bias Personal Digital Assistants (PDAs) Handheld Computers Digital Still Cameras Cellular Phones WebPad White LED Driver Local 3V to 5V Conversion
Ordering Information
ORDER NUMBER
G5103T11U
ORDER NUMBER (Pb Free)
G5103T11Uf
MARKING
5103x
TEMP. RANGE
-40C ~ +85C
PACKAGE
SOT-23-5
Pin Configuration
Typical Application Circuit
VIN 2.5V to 4.2V SW 1 5 VCC VCC
10H
16V 12mA SW 1M
GND 2
G5103 G963
4 SHDN 4.7F
G5103
SHDN GND 80.6k FB 1F
FB 3
SOT-23-5
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Global Mixed-mode Technology Inc.
Absolute Maximum Ratings
SW to GND.........................................-0.3V to +18V FB to GND............... .............................-0.3V to VCC VCC, SHDN to GND....................................-0.3V to +7V Operating Temperature Range (Note 1)..-40C to +85C
G5103
Junction Temperature .......................................+125C Storage Temperature.........................-65C to +150C Reflow Temperature (soldering, 10sec)..............260C
Stress beyond those listed under "Absolute Maximum Rating" may cause permanent damage to the device.
Electrical Characteristics
(VCC = 3.6V, V SHDN = 3.6V, TA = 25C)
PARAMETER
Input Voltage Range Quiescent Current FB Comparator Trip Point Output Voltage Line Regulation FB Pin Bias Current (Note 2) Switch Off Time Switch VDS(ON) Switch Current Limit
SHDN Pin Current
SHDN Input Voltage High SHDN Input Voltage Low
CONDITIONS
Not Switching V SHDN = 0V
MIN
2.5
TYP
20 0.1
MAX
6.5 35 1 1.22 80
UNITS
V A A V %/V nA ns s mV mA A V V A
1.18 2.5V 1V VFB < 0.6V ISW = 300mA 300 0.9
1.2 -0.05 30 500 1.6 250 350 0.1
350 400 1 0.25
Switch Leakage Current
Switch Off, VSW = 16V
0.01
5
Note 1: The G5103 are guaranteed to meet performance specifications from 0C to 85C. Specifications over the -40C to 85C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 2: Bias current flows into the FB pin.
Block Diagram
L1 VIN C1 VCC SHDN SW C2 VOUT
BIAS VOUT
SHUTDOWN LOGIC PUMP CONTROL OC DRIVER COMP en_sw + TOFF PULSE CONTROL
R1 +
ERROR COMP
FB R2
1.2V
VREF
GND
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Typical Performance Characteristics
(VCC=+3.6V, V SHDN =+3.6V, L=10H, TA=25C, unless otherwise noted.)
G5103
Efficiency vs. Load Current
90
VIN=4.2V VIN=3.6V
Output Voltage vs. Load Current
17
80
Efficiency (%)
70 60 50 40
VIN=2.7V
Output Voltage (V)
16.5
VIN=2.7V
VIN=4.2V
16
15.5
VOUT=16V
30
0.1 1 10 100
15
1 2 3 4 5 6 7 8 9 10
Load Current (mA)
Load Current (mA)
Vds_on vs. Temperature
500 50
Quiescent Current vs. Temperature
Quiescent Current (A)
Switch Vds_on (mV)
400 VIN=2.7V 300
40
30
VIN=4.2V
200
VIN=4.2V
20
VIN=2.7V
100
-20 0
10
Temperature (C)
20
40
60
80
100
-20
0
20
40
60
80
100
Temperature (C)
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Global Mixed-mode Technology Inc.
Typical Performance Characteristics (Continued)
G5103
Feedback Voltage vs. Temperature
1.22
FB Bias Current vs. Temperature
30 VIN=2.7V
Feedback Bias Current (nA)
Feedback Voltage (V)
1.21 VIN=2.7V 1.2
25
20 VIN=4.2V
1.19
VIN=4.2V
15
-20 0 20 40 60 80 100
1.18
-20 0 20 40 60 80 100
Temperature (C)
Temperature (C)
Switch Current Limit vs. Temperature
450
Load Transient
Peak Current (mA)
400
VIN=4.2V
350
VIN=2.7V
300
250
-20 0 20 40 60 80 100
Temperature (C)
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Global Mixed-mode Technology Inc.
Pin Description
PIN
1 2 3 4 5
G5103
NAME
SW GND FB
SHDN
FUNCTION
Switch Pin. The drain of the internal NMOS power switch. Connect this pin to inductor. Ground. Feedback Pin. Set the output voltage by selecting values for R1 and R2 (see Block Diagram): R1 = R2
VOUT -1 1.2
VCC
Active-Low Shutdown Pin. Tie this pin to logic-high to enable the device or tied it to logic-low to turn this device off. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible.
Function Description
The G5103 is a boost converter with a NMOS switch embedded (refer to Block Diagram). The boost cycle is getting started when FB pin voltage drop below 1.2V as the NMOS switch turns on. During the switch on period, the inductor current ramps up until 350mA current limit is reached. Then turns the switch off, while the inductor current flows through external schottky diode, and ramps down to zero. During the switch off period, the inductor current charges output capacitor and the output voltage is boosted up. This pumping mechanism continues cycle by cycle until the FB pin voltage exceed 1.2V and entering the none switching mode. In this mode, the G5103 consumes as low as 20uA typically to save battery power.
Where VD = 0.4V (Schottky diode voltage), ILIM = 350mA and tOFF = 500ns. A larger value can be used to lightly increase the available output current, but limit it to about twice the calculating value. When too large of an inductor will increase the output voltage ripple without providing much additional output current. In varying VIN condition such as battery power applications, use the minimum VIN value in the above equation. A smaller value can be used to give smaller physical size, but the inductor current overshoot will be occurs (see Current Limit Overshoot section). Inductor Selection--SEPIC Regulator For a SEPIC regulator using the G5103, the approximate inductance value can be calculated by below formula. As for the boost inductor selection, a larger or smaller value can be used. L=2 VOUT + VD ILIM x tOFF
Applications Information
Choosing an Inductor There are several recommended inductors that work well with the G5103 in Table 1. Use the equations and recommendations in the next few sections to find the proper inductance value for your design. Table 1. Recommended Inductors
PART
LQH3C4R7 LQH3C100 LQH3C220 CD43-4R7 CD43-100 CDRH4D18-4R 7 CDRH4D18-100 DO1608-472 DO1608-103 DO1608-223
VALUE(H) MAX DCR ()
4.7 10 22 4.7 10 4.7 10 4.7 10 22 0.26 0.30 0.92 0.11 0.18 0.16 0.20 0.09 0.16 0.37
VENDOR
Murata www.murata.com Sumida www.sumida.com
Current Limit Overshoot The G5103 use a constant off-time control scheme, the power switch is turned off after the 350mA current limit is reached. When the current limit is reached and when the switch actually turns off, there is a 100ns delay time. During this time, the inductor current exceeds the current limit by a small amount. The formula below can calculate the peak inductor current. IPEAK = ILIM + VIN(MAX) - VSAT x 100ns L
Coilcraft www.coilcraft.com
Inductor Selection--Boost Regulator The appropriate inductance value for the boost regulator application may be calculated from the following equation. Select a standard inductor close to this value. L= VOUT-VIN(MIN)+VD x tOFF ILIM
Where VSAT = 0.25V (switch saturation voltage). When the systems with high input voltages and uses smaller inductance value, the current overshoot will be most apparent. This overshoot can be useful as it helps increase the amount of available output current. To use small inductance value for systems design, the current limit overshoot can be quite high. Even if it is internally current limited to 350mA, the power switch of the G5103 can operate larger currents without any problem, but the total efficiency will suffer. The IPEAK is keep below 500mA for the G5103 will be obtained best performance.
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Global Mixed-mode Technology Inc.
Capacitor Selection Low ESR (Equivalent Series Resistance) capacitors should be used at the output to minimize the output ripple voltage and the peak-to-peak transient voltage. Multilayer ceramic capacitors (MLCC) are the best choice, as they have a very low ESR and are available in very small packages. Their small size makes them a good match with the G5103's SOT-23 package. If solid tantalum capacitors (like the AVX TPS, Sprague 593D families) or OS-CON capacitors are used, they will occupy more volume than a ceramic ones and the higher ESR increases the output ripple voltage. Notice that use a capacitor with a sufficient voltage rating. A low ESR surface-mount ceramic capacitors also make a good selection for the input bypass capacitor, which should be placed as close as possible to the G5103. A 4.7F input capacitor is sufficient for most applications. Diode Selection For most G5103 applications, the high switching frequency requires a high-speed rectifier Schottky diodes, such as the MBR0520 (0.5A, 20V) with their low forward voltage drop and fast switching speed, are rec-
G5103
ommended. Many different manufacturers make equivalent parts, but make sure that the component is rated to operate at least 0.35A. To achieve high efficiency, the average current rating of the Schottky diodes should be greater than the peak switching current. Choose a reverse breakdown voltage greater than the output voltage. Lowering Output Voltage Ripple The G5103 supplies energy to the load in bursts by ramping up the inductor current, then delivering that current to the load. To use low ESR capacitors will help minimize the output ripple voltage, but proper selection of the inductor and the output capacitor also plays a big role. If a larger inductance value or a smaller capacitance value is used, the output ripple voltage will increase because the capacitor will be slightly overcharged each burst cycle. To reduce the output ripple, increase the output capacitance value or add a 10pF feed-forward capacitor in the feedback network of the G5103 (see the circuits in the Typical Applications section). To add this small, inexpensive 10pF capacitor will greatly reduce the output voltage ripple.
Typical Applications
Boost Converter
SEPIC Converter
L1 4.7H VIN 2.5V to 4.2V VCC SW
D1
L1 10H 5V 50mA VIN 2.5V to 4.2V VCC R1 390k SW
C3 1F
D1 3.3V 60mA
L2 10H C2 22F
R1 470k C2 22F
G5103
SHDN C1 4.7F GND FB R2 120k
G5103
SHDN C1 4.7F GND FB R2 270k
L1:MURATA LQH3C4R7M24 D1:MOTOROLA MBR0520
L1,L2:MURATA LQH3C100K24 D1:MOTOROLA MBR0520
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Global Mixed-mode Technology Inc.
White LED Driver
G5103
L1 10H/0.5A VBAT 2.5V~5.5V C1 4.7F VCC SW
D1
MBR0520 C2 1F D2(Optional) 18V
G5103
ON/OFF Control SHDN FB
GND
R2 R3 VBIAS(+3.3V) 308k_1% R4 660k_1% PWM Dimming Control VH=3.3V VL=0V Freq=160~240Hz 120k_1% R1 30_1%
PWM Dim
Dimming Ratio>50:1 Drive 2~4 White LEDs
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Global Mixed-mode Technology Inc.
Package Information
G5103
C L
D
E
H
e1 e
1
A A2 A1
b
Note: 1. Package body sizes exclude mold flash protrusions or gate burrs 2. Tolerance 0.1000 mm (4mil) unless otherwise specified 3. Coplanarity: 0.1000mm 4. Dimension L is measured in gage plane SYMBOLS
A A1 A2 b C D E e e1 H L 1
MIN
1.00 0.00 0.70 0.35 0.10 2.70 1.40 --------2.60 0.37 1
DIMENSIONS IN MILLIMETERS NOM
1.10 ----0.80 0.40 0.15 2.90 1.60 1.90(TYP) 0.95 2.80 -----5
MAX
1.30 0.10 0.90 0.50 0.25 3.10 1.80 --------3.00 ----9
Taping Specification
PACKAGE
SOT-23-5
Feed Direction
Q'TY/REEL
3,000 ea
SOT-23-5 Package Orientation
GMT Inc. does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and GMT Inc. reserves the right at any time without notice to change said circuitry and specifications.
Ver: 1.1 Sep 20, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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