Datasheet

UNISONIC TECHNOLOGIES CO., LTD
UC3552
CMOS IC
PWM DC-DC CONVERTER
WITH INTERNAL SWITCH AND
SOFT-START

DESCRIPTION
The UTC UC3552 is a step-up PWM DC-DC converter with a
internal switch which is 1.6A, 0.23Ω. UTC UC3552 offers users
flexibility in determining loop dynamics and adjusting operating
frequency cause it’s equipped with an external compensation
pin ,and it also allows the use of small, low equivalent resistance
(ESR) ceramic output capacitors. UTC UC3552 is capable of
converting a standard input of 3.3V to multiple outputs of 8V, − 8V ,
and 23V. Otherwise, filtering and loop performance are enhanced
and facilitated by a high switching frequency of either 640 kHz
or1.3MHz.
As a power-smart design in shutdown mode a soft-start with an
external capacitor that sets the input current ramp rate, reduces the
current consumption to 0.1μA. A mere 2.6V input yields an
impressive output voltage to 12V when operating.

FEATURES
* 1.6A, 0.23Ω, internal switch
* High efficiency: 90%
* Adjustable output: VDD to 12V
* Adjustable frequency: 640kHz or 1.3MHz
* Wide input range: +2.6V ~ +5.5V
* Low shutdown current: 0.1μA
* Programmable soft-start

ORDERING INFORMATION
Ordering Number
UC3552G-S08-R
UC3552G-SM1-R
www.unisonic.com.tw
Copyright © 2016 Unisonic Technologies Co., Ltd
Package
SOP-8
MSOP-8
Packing
Tape Reel
Tape Reel
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QW-R502-134.C
UC3552
CMOS IC

MARKING

PIN CONFIGURATION

PIN DESCRIPTION
PIN NO. PIN NAME
1
EO
2
IN
I/O
I
I
3
SHDN
4
5
6
GND
SW
VDD
O
7
FREQ
I
8
SS
I
I
DESCRIPTION
Compensation pin for Error Amplifier
Feedback pin with a typical reference voltage of 1.24V
Shutdown control pin. The device will turn off when SHDN is low
Ground
Switch pin
Power supply pin
Frequency select pin. Switch oscillator frequency to 640kHz when FREQ is low, and
1.3MHz when FREQ is high
Soft-Start control pin. No soft-start when the pin is left open
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QW-R502-134.C
UC3552

CMOS IC
BLOCK DIAGRAM
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UC3552

CMOS IC
ABSOLUTE MAXIMUM RATINGS
SW to GND
PARAMETER
SYMBOL
RATINGS
-0.3 ~ +14
UNIT
V
IN, SHDN , VDD , FREQ to GND
-0.3 ~ +6
V
SS, EO to GND
RMS SW Pin Current
-1.3V ~ (VDD+0.3V)
ISW
1.2
SOP-8
350
Continuous Power Dissipation (TC = 70°C)
PD
300
MSOP-8
Junction Temperature
TJ
+125
Operating Temperature
TOPR
-20 ~ +85
Storage Temperature
TSTG
-45 ~ +125
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.

V
A
mW
mW
°C
°C
°C
ELECTRICAL CHARACTERISTICS
TC = +25°C, VDD = SHDN = 3V, FREQ = GND, unless otherwise specified.)
PARAMETER
SYMBOL
TEST CONDITIONS
Input Supply Voltage
VDD
When VDD is rising, typical hysteresis
is 40mV; SW remains off below this
VDD Under Voltage Lockout
UVLO
level
VDD = 1.3V, not switching
Quiescent Current
IDD
VDD = 1.0V, switching
SHDN = GND
Shutdown Current
ISC
ERROR AMPLIFIER
Feedback Voltage
VIN
Level to produce VEO = 1.24V
VDD Input Bias Current
II(BIAS)
VIN= 1.24V
Level to produce VEO = 1.24V,
Feedback-Voltage Line
Regulation
2.6V < VDD < 5.5V
Transconductance
gm
∆I = 5µA
Voltage Gain
GV
OSCILLATOR
FREQ = GND
Frequency
fOSC
FREQ = VDD
FREQ = GND
Maximum Duty Cycle
tDUTY
FREQ = VDD
N-CHANNEL SWITCH
Current Limit
ILIMIT
VDD = 1V, Duty Cycle = 65%
On-Resistance
RON
ISW = 1.2A
Leakage Current
ILEAK
VSW = 12V
SOFT-START
Reset Switch Resistance
Charge Current
VSS = 1.2V
CONTROL INPUTS
SHDN , FREQ; VDD = 2.6V ~ 5.5V
Input Low Voltage
VIL
Input High Voltage
Hysteresis
FREQ Pull-Down Current
SHDN Input Current
VIH
SHDN , FREQ; VDD = 2.6V ~ 5.5V
MIN
2.6
TYP
MAX
5.5
UNIT
V
2.25
2.38
2.52
V
0.21
1.2
0.35
5.0
mA
0.1
10.0
µA
1.240
0
1.258
40
V
nA
0.05
0.15
%/V
70
105
1500
240
µA/V
V/V
540
1100
79
640
1320
85
85
740
1600
92
1.2
1.6
0.23
0.01
2.3
0.50
20.00
A
Ω
µA
1.5
4.0
300
7.0
Ω
µA
0.3VDD
V
1.22
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
1.8
%
V
0.7VDD
SHDN , FREQ
IFREQ
I SHDN
kHZ
0.1VDD
5.0
9.0
V
µA
0.001
1.000
µA
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UC3552

CMOS IC
TYPICAL APPLICATION CIRCUIT
L
VDD
2.6V~5V
6.8μH
VDD
VOUT
SW
ON/OFF
SHDN
D1
R1
COUT
33μF
C1
3.3μF
274kΩ
IN
C2
0.47μF
UTC
UC3552
SS
CSS
R2
44.2kΩ
27nF
1.2MHz
GND
FREQ
EO
CEO2
33pF
640KHz
REO
47KΩ
CEO
1.3nF
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QW-R502-134.C
UC3552

CMOS IC
IN A SEPIC CONFIGURATION
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UC3552
CMOS IC
MULTIPLE-OUTPUT TFT LCD POWER SUPPLY

EO
150kΩ
SHDN
SS
27nF
18pF
UTC UC3552
V1
274kΩ
C5
C4
3.3μF 3.3μF
C3
3.3μF
IN
FREQ
GND
VDD
44.2kΩ
VDD
C1 3.0V ~ 3.6V
3.3μF
C2
0.47μF
SW
L1
D1
6.8μH
V3
D2
1μF
3.3μF
V2
D4
+26V
5mA
0.1μF
0.1μF
1μF
D3
1μF
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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www.unisonic.com.tw
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