Datasheet

UNISONIC TECHNOLOGIES CO., LTD
USR1101
Preliminary
LINEAR INTEGRATED CIRCUIT
5V/12V SYNCHRONOUS
BUCK PWM DC-DC
CONTROLLER

DESCRIPTION
The UTC USR1101 is a high efficiency synchronous buck
PWM controller, with operating at fixed 300kHz frequency,
Internal soft-start, frequency compensation networks and
integrates all of the control, output adjustment, monitoring and
protection functions into a single package.
Adjustable over-current protection (OCP) monitors the voltage
drop across the RDS(ON) of the lower MOSFET for synchronous
buck PWM DC-DC controller.

SOP-8
FEATURES
* Operating with 5V or 12V supply voltage
* Drives all low cost N-channel MOSFETs
* PWM control mode
* 300kHz fixed frequency
* Internal soft-start
* Over-current fault monitor on MOSFET, no current sense
resistor required
* RoHS compliant and 100% lead (Pb)-free

ORDERING INFORMATION
Ordering Number
USR1101G-S08-R
Package
SOP-8
Packing
Tape Reel
USR1101G-S08-R

(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) S08: SOP-8
(3)Green Package
(3) G: Halogen Free and Lead Free
MARKING
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Copyright © 2015 Unisonic Technologies Co., Ltd
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USR1101

Preliminary
LINEAR INTEGRATED CIRCUIT
PIN CONFIGURATION
BOOT 1
8 NC
UGATE 2
7 OPS
USR1101
GND 3
LGATE 4

6 FB
5 VCC
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
7
8
PIN NAME
BOOT
UGATE
GND
LGATE
VCC
FB
OPS
NC
DESCRIPTION
High-Side gate drive boost
Upper gate driver output
Ground
Lower gate drive output
Supply voltage
Feedback voltage
Over-current setting and shutdown
No bonding
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USR1101

Preliminary
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
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USR1101

Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VCC
16
V
Power Dissipation (TA=25°C) (Note 1)
PD
0.625
W
Storage Temperature
TSTG
-65~150
°C
Junction Temperature
TJ
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
160
UNIT
°С/W
RECOMMENDED OPERATING CONDITIONS (Note 2)
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VCC
5±5%,12±10%
V
Ambient Temperature
TA
0~70
°C
Junction Temperature
TJ
0~125
°C
Notes: 1. θJA is measured in the natural convection at TA=25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard.
2. The device is not guaranteed to function outside its operating conditions.

ELECTRICAL CHARACTERISTICS (VCC=5V/12V, TA=25°C, unless otherwise specified)
PARAMETER
VCC Supply Current
Nominal Supply Current
Power-On Reset
POR Threshold
Hysteresis
Switcher Reference
Reference Voltage
Oscillator
Free Running Frequency
Ramp Amplitude
PWM Controller Gate Drivers (VCC=12V)
Dead Time
Protection
FB Under-Voltage Trip
OC Current Source
Soft-Start Interval
SYMBOL
ICC
VCCRTH
VCCHYS
MIN
UGATE and LGATE Open
TYP
MAX UNIT
6
15
mA
4.1
0.5
4.5
0.35
V
V
VCC Rising
VREF
VCC=12V
0.784
0.8
0.816
V
fOSC
∆VOSC
VCC=12V
VCC=12V
250
300
1.5
350
kHz
VP-P
100
ns
80
45
%
μA
ms
TDT
∆FBUVT
IOC
TSS
UNISONIC TECHNOLOGIES CO., LTD
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TEST CONDITIONS
FB Falling
70
75
40
2.5
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USR1101

Preliminary
LINEAR INTEGRATED CIRCUIT
APPLICATION INFORMATION
OCP
Sense the low-side MOSFET’s RDS(ON) to set over-current trip point.
Connecting a resistor (ROCSET) from this pin to the source of the upper MOSFET and the drain of the lower
MOSFET sets the over-current trip point. ROCSET, an internal 40μA current source, and the lower MOSFET on
resistance, RDS(ON), set the converter over-current trip point (IOCSET) according to the following equation:
IOCSET 
40A  ROCSET  0.4V
RDS(ON) of the lower MOSFET
Shutdown
Pulling low the OPS pin by a small single transistor can shutdown the UTC USR1101 PWM controller as shown in
typical application circuit.

TYPICAL APPLICATION CIRCUIT
+5V~+12V
VIN
D1
1N4148
R1
10
UTC USR1101
1
5
C1
1µF
6
3
BOOT
UGATE
VCC
NC
FB
OPS
GND
LGATE
2
C3
1µF
C2
0.1µF
M1
8
7
4
C4
470µF
L1
3µH
ROCSET
M2
VOUT
COUT
1000µF×3
Disable
R2
32
R3
68
R4
C5
200-1k 0.1-0.33µF
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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