UNISONIC TECHNOLOGIES CO., LTD
USR1051
Preliminary
LINEAR INTEGRATED CIRCUIT
3 A SYNCHRONOUS BUCK
REGULATOR
DESCRIPTION
The UTC
USR1051
is a high efficiency, 3A synchronous buck
regulator. The UTC
USR1051
works from 5V to 23V input voltage
range, and provides up to 3A of continuous output current with an
output voltage adjustable down to 0.8V.
The UTC
USR1051
comes in an exposed pad HSOP-8
package and is rated over a -40°C~+85°C operating ambient
temperature range.
HSOP-8
FEATURES
* Synchronous Buck
* 5V~23V operating input voltage range
* High efficiency
* Internal soft start
* Output voltage adjustable to 0.8V
* 3A continuous output current
* Cycle-by-cycle current limit
* 400kHz PWM operation
* Pre-bias start-up
* Thermal shutdown
* Short-circuit protection
* Exposed pad HSOP-8 package
ORDERING INFORMATION
Ordering Number
Lead Free
USR1051L-SH2-T
USR1051L-SH2-R
Halogen Free
USR1051G-SH2-T
USR1051G-SH2-R
Package
HSOP-8
HSOP-8
Packing
Tube
Tape Reel
www.unisonic.com.tw
Copyright © 2013 Unisonic Technologies Co., Ltd
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USR1051
PIN CONFIGURATION
Preliminary
LINEAR INTEGRATED CIRCUIT
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
7
8
Exposed pad
PIN NAME
PGND
V
IN
AGND
FB
COMP
EN
NC
NC
LX
DESCRIPTION
Power ground
Supply voltage input
Analog ground
Feedback input
External loop compensation pin
Enable pin
No Connect Pin.
No Connect Pin.
Switching node
BLOCK DIAGRAM
V
IN
Current
Source
Bias
SENSE
Driver
PWM
PWM
LATCH
Dead Time
Control
EN
Start Up
VREF
REF_0.8V
OSC
FB
EA
SLOPE
LX
Driver
COMP
AGND
PGND
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USR1051
PARAMETER
Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING
RATINGS
UNIT
Supply Voltage
23
V
LX to AGND
-0.7~V
IN
+0.3
V
LX to AGND (20ns)
-5~22
V
EN to AGND
-0.3~V
IN
+0.3
V
FB, SS, COMP to AGND
-0.3~6.0
V
PGND to AGND
-0.3~+0.3
V
Ambient Temperature
T
A
-40~+85
°C
Junction Temperature
T
J
+150
°C
Storage Temperature
T
STG
-65~+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.
SYMBOL
V
IN
THERMAL DATA
PARAMETER
Junction to Ambient (Note 2)
SYMBOL
θ
JA
RATING
50
UNIT
°C/W
RECOMMENDED OPERATING CONDIIONS
PARAMETER
Supply Voltage
Output Voltage
SYMBOL
V
IN
V
OUT
RATINGS
5~23
0.8~0.85×V
IN
UNIT
V
V
ELECTRICAL CHARACTERISTICS (Note 3)
(T
A
=25°C, V
IN
=V
EN
=12V, V
OUT
=3.3V, unless otherwise specified)
PARAMETER
Supply Voltage
Supply Current (Quiescent)
Shutdown Supply Current
Feedback Voltage
Load Regulation
Line Regulation
Feedback Voltage Input Current
EN Input Threshold
SS Time
MODULATOR
Frequency
Maximum Duty Cycle
Controllable Minimum On Time
Current Sense Transconductance
Error Amplifier Transconductance
PROTECTION
Current Limit
SYMBOL
TEST CONDITIONS
V
IN
I
IN
I
OUT
=0, V
FB
=1.2V, V
EN
>2V
I
OFF
V
EN
=0V
V
FB
T
A
=25 °C
MIN
5
TYP
3.5
1
0.8
0.5
1
MAX UNIT
23
V
5
mA
10
µA
0.812
V
%
%
200
nA
0.6
V
V
ms
550
150
7
180
3.5
kHz
%
ns
A/V
µA/V
0.788
I
FB
V
EN
Off Threshold
On Threshold
C
SS
=16nF
2
2
380
85
450
f
O
D
MAX
T
MIN
4.5
A
T
J
Rising
150
°C
Over-Temperature Shutdown Limit
100
°C
T
J
Falling
Notes: 1. Devices are inherently ESD sensitive, handling precautions are required. Human body model rating: 1.5
kΩ in series with 100pF.
2. The value of
θ
JA
is measured with the device mounted on a 1-in
2
FR-4 board with 2oz. Copper, in a still air
environment with T
A
=25°C. The value in any given application depends on the user’s specific board
design.
3. Specification in BOLD indicate an ambient temperature range of -40°C~+85°C. These specifications are
guaranteed by design.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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USR1051
Preliminary
LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT
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.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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