UTC-IC UC3550G-XX-AF5-R

UNISONIC TECHNOLOGIES CO., LTD
UC3550
CMOS IC
PWM CONTROLLED, PWM/PFM
SWITCHABLE STEP-UP DC-DC
CONTROLLER
3
„
1
DESCRIPTION
The UTC UC3550 series is a compact, high efficiency, step-up
DC/DC controllers includes an error amplifier, oscillator, PWM
comparator, skip cycle comparator, voltage reference, soft-start, and
high speed lower ON-resistance driver for driving external power
devices (NMOS or NPN) ,Additionally, a CE (chip enable) function that
reduces power consumption during shut-down mode.
That typically operated from a single-or dual-cell battery packs. It
have a driver pin ,ext pin, for connecting to an external transistor(NMOS
or NPN). a lower ON-resistance external transistor can obtain larger
output current. With only external components, this series allow a
simple means to accommodate high output current applications.
The UTC UC3550 series goes automatically into skip switching
cycles under light load condition to maintain high efficiency.
„
2
5
4
SOT-25
FEATURES
* Input Voltage Range:0.9~8V
* Output Voltage Range:1.8~6V Programmable in 0.1V with High
Accuracy ± 2.5%
* High Efficiency 88% (Typ.)
* Low Start-up Voltage of 0.9V Typical at IOUT = 1.0mA
* Oscillator Frequency: 300kHz.(±20%)
* Chip Enable Pin with Pull-up Current Source
* High Output Current up to 1000mA (VIN = 2.0V, VOUT =3.3V)
„
ORDERING INFORMATION
Order Number
UC3550G-xx-AF5-R
Package
SOT-25
www.unisonic.com.tw
Copyright © 2010 Unisonic Technologies Co., Ltd
Packing
Tape Reel
1 of 10
QW-R502-082,B
UC3550
CMOS IC
MARKING INFORMATION
„
PACKAGE
VOLTAGE CODE
SOT-25
33:3.3V
50:5.0V
„
PIN CONFIGURATION
„
PIN DESCRIPTION
PIN NO
PIN NAME
1
CE
2
3
4
5
OUT
NC
GND
EXT
MARKING
DESCRIPTION
Chip Enable:
The chip is enabled if a voltage equal to or greater than 1.0V or left floating is applied.
The chip is disabled if a voltage less than 0.3V is applied.
Output voltage monitor, IC internal power supply
No connection
Ground
External transistor drive
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UC3550
„
CMOS IC
BLOCK DIAGRAM
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UC3550
„
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VOUT
-0.3~8
V
VEXT
-0.3 ~ 8
V
EXT Voltage
EXT Sink/Source Current
IEXT
-150 ~ +150
mA
CE Input Voltage Range
VCE
-0.3 ~ 12.0
V
CE Input Current Range
ICE
-155 ~ 155
mA
Power Dissipation (Ta=25°C)
PD
500
mW
Junction Temperature
TJ
+150
°C
Operating Temperature
TOPR
-40 ~ +85
°C
Storage Temperature
TSTG
-55 ~ +150
°C
Note: 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.
„
THERMAL DATA
PARAMETER
Junction to Ambient
„
SYMBOL
θJA
RATINGS
250
UNIT
°C/W
ELECTRICAL CHARACTERISTICS (Ta=25°C, fOSC=300kHz, unless otherwise specified)
UC3550-3.3V
PARAMETER
OSCILLATOR
Frequency
Frequency Temperature Coefficient
Maximum PWM Duty Cycle
Minimum Start-up Voltage
Minimum Start-up Voltage
Minimum Start-up Voltage
Temperature Coefficient
Minimum Operation Hold Voltage
Soft-Start Time
CE (PIN 1)
CE Input Voltage :
High State, Device Enabled
Low State, Device Disabled
CE Input Current :
High State, Device Enabled
Low State, Device Disabled
EXT (PIN 5)
EXT “H”
ON Resistance
EXT “L”
TOTAL DEVICE
Output Voltage
Output Voltage
temperature coefficient
Operating Current
Stand-by Current
Off-State Current
Efficiency
SYMBOL
fOSC
△f
DMAX
VSTART1
VSTART2
TEST CONDITIONS
VOUT=VSET×0.96
Ta=-40°C ~ 85°C
VOUT=VSET×0.96
IOUT=0mA
IOUT=1mA
TYP
MAX
UNIT
240
300
0.10
80
800
900
360
kHz
%/°C
%
mV
mV
70
△VSTART Ta=-40°C ~ 85°C
VOPR
tSS
IOUT=0mA
VOUT=VSET
VCEH
VCEL
VOUT=VSET×0.96
ICEH
ICEL
VOUT=VCE=5.0V
VOUT=5.0V, VCE=0V
REXTH
REXTL
90
900
1000
-1.6
600
60
mV/°C
700
250
mV
ms
680
mV
mV
0
0.15
0.5
0.5
μA
μA
11
8
15
12
Ω
Ω
3.3
3.383
900
-0.5
0
VEXT=VOUT-0.4V
VEXT=0.4V
VOUT
3.218
V
△VOUT
Ta=-40 ~ 85°C
150
IDD
ISTN-BY
VOUT=VCE=VSET×0.96
VOUT=VCE=VSET+0.5V
VOUT=5.0V, VCE=0V,
Ta=-40 ~ +85°C
IOUT = 200mA, VIN = 2.0V
103
15
160
38
μA
μA
0.6
1.5
μA
IOFF
η
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www.unisonic.com.tw
MIN
80
88
ppm/°C
%
4 of 10
QW-R502-082,B
UC3550
„
CMOS IC
ELECTRICAL CHARACTERISTICS (Cont.)
UC3550-5.0V
PARAMETER
OSCILLATOR
Frequency
Frequency Temperature Coefficient
Maximum PWM Duty Cycle
Minimum Start-up Voltage
Minimum Start-up Voltage
Minimum Start-up Voltage
Temperature Coefficient
Minimum Operation Hold Voltage
Soft-Start Time
CE (PIN 1)
CE Input Voltage :
High State, Device Enabled
Low State, Device Disabled
CE Input Current :
High State, Device Enabled
Low State, Device Disabled
EXT (PIN 5)
EXT “H”
ON Resistance
EXT “L”
TOTAL DEVICE
Output Voltage
Output Voltage temperature
coefficient
Operating Current
Stand-by Current
Off-State Current
Efficiency
SYMBOL
fOSC
△f
DMAX
VSTART1
VSTART2
TEST CONDITIONS
VOUT=VSET×0.96
Ta=-40°C ~ 85°C
VOUT=VSET×0.96
IOUT=0mA
IOUT=1mA
TYP
MAX
UNIT
240
300
0.1
80
800
900
360
kHz
%/°C
%
mV
V
70
△VSTART Ta=-40°C ~ 85°C
VOPR
tSS
IOUT=0mA
VOUT=VSET
VCEH
VCEL
VOUT=VSET×0.96
ICEH
ICEL
VOUT=VCE=5.0V
VOUT=5.0V, VCE=0V
REXTH
REXTL
VEXT=VOUT-0.4V
VEXT=0.4V
VOUT
△VOUT
IDD
ISTN-BY
IOFF
η
90
900
1
-1.6
600
60
mV/°C
700
200
mV
ms
680
mV
mV
0
0.15
0.5
0.5
μA
μA
6
6
10
10
Ω
Ω
5
5.125
900
-0.5
0
4.875
V
Ta=-40 ~ 85°C
150
VOUT=VCE=VSET×0.96
VOUT=VCE=VSET+0.5V
VOUT=5.0V, VCE=0V,
Ta=-40 ~ +85°C
IOUT = 200mA, VIN = 3.0V
136
15
220
38
μA
μA
0.6
1.5
μA
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www.unisonic.com.tw
MIN
80
88
ppm/°C
%
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UC3550
„
CMOS IC
TYPICAL STEP-UP CONVERTER APPLICATION
10uH
VIN
VOUT
220uF
EXT
CE
1
5
OUT
UTC
UC3550
2
10uF
NC
0.1µ 3
GND
4
Step-up Converter using external MOSFET
10uH
VIN
VOUT
Cb 3000P
1
OUT
2
10uF
NC
0.1µ 3
220uF
EXT
CE
5
Rb 560
UTC
UC3550
GND
4
Step-up Converter using external NPN
Recommended components
Nmos tR :XP161A0390PR/ (Torex) or NTGS3446T1(ON SEMI)
L
:10Uh(Sunida CD54 fosc=300kHz)
SD
:MA737, or MBRM110L
CIN
:10V 10uF (tantalum)
CL
:16V220uF (tantalum)
NPN tR type
tR
:2SD1628(Sanyo),MMJT9410
Rb
:500~1000Ω(Adjust according to load and Tr. hFE levels)
Cb
:3000p(ceramic type)
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QW-R502-082,B
UC3550
„
CMOS IC
EXTERNAL COMPONENT SELECTION
Inductor Selection
An inductor value of 10uH performs well in most application. The UC3550 series also work with inductors in the
4.7uH to 12uH range. An inductor with higher peak inductor current tends a higher output voltage ripple(IPEAK x
output filter capacitor ESR). The inductor’s DC resistance significantly affects efficiency.
Output Capacitor Selection
The output ripple voltage(IPEAK x output filter capacitor ESR)is the product of the peak inductor current and the
output capacitor Equivalent Series Resistance (ESR). Best performances are obtained with good high frequency
characteristics capacitors and low ESR. The best compromise for the value of the Output Capacitance is 220F
Tantalum Capacitor. The output capacitor as close as possible to the device pins.
Input Capacitor Selection
The Input Capacitor is required to compensate, if present, the series impedance between the Supply Voltage
Source and the Input Voltage of the Application. A value of 10 F is enough to guarantee stability for distances less
than 2". In any case we suggest to connect both capacitors, The input capacitor as close as possible to the device
pins.
Diode Selection
The Schottky diode with an high switching speed and a very low Forward Voltage (VF) is needed. Higher VF may
cause lost power as heat in the diode, with a decrease of the Efficiency. Moreover, since the Output Voltage pin is
also used as the device Supply Voltage, the Start-up Voltage (see related plots) is strictly due to the diode Forward
Voltage at the rated Forward Current.
External Component Selection
An enhancement N-channel MOSFET or a bipolar NPN transistor can be used as the external switch transistor.
since enhancement N-channel MOSFET is a voltage driven device, it is a more efficient switch than a BJT transistor.
However, he MOSFET requires a higher voltage to turn on as compared with BJT transistor
For enhancement N-channel MOSFET ( it is especially importance for RDS(ON),typically<0.1Ω, threshold voltage,
VGS(TH) must be<VOUT, typically<1.5V.
For bipolar NPN transistor, continuous collector current typically 1A to 4A and VCE(SAT)<0.2V. the driving capability
is determined by the DC current gain, HFE, of the transistor and the base resistor, Rb. Moreover, a speed-up
capacitor, Cb should be connected in paralled with Rb to reduce switch loss and improve efficiency.
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QW-R502-082,B
UC3550
TYPICAL CHARACTERISTICS
1
VOUT=5.0V
0.1
VOUT=3.0V
2
3
4
Input Voltage, VIN (V)
10
1
0.1
0.01
1
5
VOUT=5.0V,
Rb=560Ω
VOUT=3.0V,
Rb=560Ω
2
5
3
4
Input Voltage, VIN (V)
6
Maximum Duty Cycle, DMAX (%)
0.01
1
No Load Input
Current vs. Input Voltage (Using BJT)
100
NO Load Input Current, IIN (mA)
NO Load Input Current, IIN (mA)
No Load Input
Current vs. Input Voltage (Using MOSFET)
10
Output Voltage, VOUT (V)
„
CMOS IC
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UC3550
TYPICAL CHARACTERISTICS(Cont.)
Efficiency vs Output Current (5.0V)
Startup/Hold Voltage, Vstart/Vhold (V)
100
Efficiency (%)
VIN=3.0V
80
VIN=2.0V
60
VIN=0.9V
40
20
0
0. 01
0.1
1
10
100
1000
Startup/Hold Voltage vs Output Current
(Using MOSFET) Output Current (3.3V)
2.0
Vstart
1.6
1.2
0.8
Vnold
0.4
0.0
0
Output Current, IOUT (mA)
EXT ON-Resistance vs Temperature
20
15
VOUT=5.0V×0.96
VEXT=VOUT-0.4V
Open-Loop Test
10
VOUT=5.0V×0.96
VEXT=0.4V
Open-Loop Test
5
0
-50
25
-
0
25
50
75
200
Ripple Voltage, VRIPPLE (mV)
ON-Resistance, (Ω)
25
20
40
60
80 100
Output Current, IC (mA)
Temperature℃
Ripple Voltage vs Output Current
180
160
VIN=2.0V
140
120
100
VIN=3.0V
VIN=1.5V
80
60
VIN=4.5V
40
20
0
0
100
200
400
600
800 1000
Output Current, IOUT (mA)
Oscilator Frequency, fosc (KHz)
Oscilator Frequency, fosc (KHz)
„
CMOS IC
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UC3550
„
CMOS IC
TYPICAL CHARACTERISTICS(Cont.)
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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