Datasheet

UNISONIC TECHNOLOGIES CO., LTD
UD05251
Preliminary
LINEAR INTEGRATED CIRCUIT
1.2MHZ, 2.5A SYNCHRONOUS
STEP-DOWN CONVERTER

DESCRIPTION
HSOP-8
The UTC UD05251 is a 1.2MHz constant frequency current
mode PWM step-down converter. It is ideal for portable
equipment requiring very high current up to 2.5A from single-cell
Lithium-ion batteries while still achieving over 90% efficiency
during peak load conditions. The UTC UD05251 also can run at
100% duty cycle for low dropout operation, extending battery life
in portable systems while light load operation provides very low
output ripple for noise sensitive applications. The UTC UD05251
can supply up to 2.5A output current from a 2.6V to 4V input
voltage and up to 3A output current from a 4V to 5.5V input
voltage. The output voltage can be regulated as low as 0.8V. The
high switching frequency minimizes the size of external
components while keeping switching losses low. The internal
slope compensation setting allows the device to operate with
smaller inductor values to optimize size and provide efficient
operation. The UTC UD05251 is available in adjustable (0.8V to
VIN) output voltage.

DFN-8(3x3)
FEATURES
* 2.6V to 5.5V Input Voltage Range
* Output Voltages from 0.6V to VIN
* High Efficiency: Up to 94%
* 1.2MHz Constant Frequency Operation
* Output Current:
Up to 2.5A Output Current for VIN=2.6V~4V
Up to 3A Output Current for VIN=4V~5.5V

1
* No Schottky Diode Required
* Current Mode Operation for Excellent Line and Load
Transient Response
* Current limit, Enable function
* Short Circuit Protect (SCP)
* Build-in Soft Start function
* ≤1µA Shutdown Current
ORDERING INFORMATION
Ordering Number
UD05251G-SH2-B-R
UD05251G-SH2-C-R
UD05251G-K08-3030-R
UD05251G-SH2-B-R
Package
HSOP-8
HSOP-8
DFN-8(3×3)
Packing
Tape Reel
Tape Reel
Tape Reel
(1)Packing Type
(1) R: Tape Reel
(2)Pin Code
(2) Refer to PIN CONFIGURATION
(3)Package Type
(3) SH2: HSOP-8, K08-3030: DFN-8(3×3)
(4)Green Package
(4) G: Halogen Free and Lead Free
www.unisonic.com.tw
Copyright © 2016 Unisonic Technologies Co., Ltd
1 of 5
QW-R115-005.c
UD05251
Preliminary
LINEAR INTEGRATED CIRCUIT
MARKING

HSOP-8
DFN-8(3×3)
PIN CONFIGURATION

SVIN 1
8 PVIN
FB 2
7 LX
UTC
UD05251-B
SGND 3
SVIN 1
8 PVIN
NC 2
6 PGND
UTC
UD05251-C
SGND 3
6 PGND
GND
GND
5 SGND
EN 4
7 LX
5 EN
FB 4
HSOP-8
HSOP-8
Top View
SVIN
1
FB
2
SGND
3
EN
4
8 PVIN
UTC
UD05251
GND
7 LX
6 LX
5 PGND
DFN-8(3×3)
PIN DESCRIPTION

PIN NO.
HSOP-8
DFN-8(3×3)
B
C
1
1
1
2
4
2
3, 5
3
3
PIN NAME
SVIN
FB
SGND
4
5
4
EN
6
6
5
PGND
7
7
6, 7
LX
8
-
8
2
8
-
PVIN
NC
DESCRIPTION
Signal Supply Input Pin
Output Feedback pin
Signal Ground Pin
Enable pin
H:normal operation
L:Shutdown
Power Ground Pin
Switch output pin. Connect external inductor here.
Minimize trace area at this pin to reduce EMI.
Power Supply Input Pin
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
2 of 5
QW-R115-005.c
UD05251

Preliminary
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
OSC
SVIN
SLOPE
COMP
PVIN
+
Isense
AMP
-
REF
0.6V
SET
Soft-Star
+
FB
Icomp
+
RESET
PWM
LOGIC
NON-OVERLAP
CONTROL
LX
-
+
Izero
COMP
Over-Temperature
and Short-Circuit
Protection
SGND
-
PGND
Enable Logic
EN
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
3 of 5
QW-R115-005.c
UD05251

Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING (TA=25°C, unless otherwise specified)
PARAMETER
PVIN, SVIN Pin Voltage
Feedback Pin Voltage
EN Pin Voltage
Switch Pin Voltage
RATINGS
UNIT
VSS+6
V
VIN+0.3
V
VIN+0.3
V
VIN+0.3
V
HSOP-8
1
mW
Power Dissipation
PD
DFN-8(3×3)
2
mW
Junction Temperature
TJ
+125
°C
Operating Temperature Range
TOPR
-40 ~ +85
°C
Storage Temperature Range
TSTG
-40 ~ +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
VIN
VFB
VEN
VLX
THERMAL RESISTANCES CHARACTERISTICS
PARAMETER
SYMBOL
RATING
UNIT
40
°C/W
Junction to Ambient
θJA
50
°C/W
Junction to Case
θJC
15
°C/W
Note: θJA is measured with the PCB copper area of approximately 1 in2 (Multi-layer). That need connect to exposed
pad.
HSOP-8
DFN-8(3×3)

ELECTRICAL CHARACTERISTICS (VIN=VEN=3.6V, TA=25°C, unless otherwise specified)
PARAMETER
Supply Voltage Range
SYMBOL
VIN
Feedback Voltage
VFB
Feedback Bias Current
Quiescent Current
Shutdown Supply Current
IFB
ICCQ
ISD
Switching Current Limit
ILIMIT
TEST CONDITIONS
TA=+25°C
TA=0°C≤TA ≤85°C
TA=-40°C≤TA≤85°C
VFB=0.65V
VFB=0.8V
VEN=0V
VIN=2.6V~4V
VIN=4V~5.5V
VIN=2.6V~5.5V
IOUT=0.01~2.5A
LX Pin
VFB=0V, IOUT=2A
Line Regulation
△VOUT/VOUT
Load Regulation
△VOUT/VOUT
Oscillation Frequency
FOSC
RDS(ON) of P-CH MOSFET
RDSON
RDS(ON) of N-CH MOSFET (Note)
RDSON
EN Pin Logic Input Threshold
VENL
Voltage
VENH
EN Pin Input Current
IEN
Efficiency
EFFI
VIN=5V, VOUT=3.3V, IOUT=2A
Thermal Shutdown
TSD
Thermal Shutdown Hysteresis
TSH
Note: Guaranteed by design.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
MIN
TYP
MAX
2.6
5.5
0.5880 0.6000 0.6120
0.5865 0.6000 0.6135
0.5820 0.6000 0.6180
±30
250
400
0.1
1
3.0
3.5
3.3
4
0.04
0.4
0.5
1
1
1.2
1.4
0.14
0.20
0.1
0.15
0.4
1.5
±0.1
±1
90
140
30
UNIT
V
V
V
V
nA
μA
μA
A
A
%/V
%
MHz
Ω
Ω
V
V
μA
%
°C
°C
4 of 5
QW-R115-005.c
UD05251

Preliminary
LINEAR INTEGRATED CIRCUIT
FUNCTION DESCRIPTIONS
Operation
UTC UD05251 is a monolithic switching mode Step-Down DC-DC converter. It utilizes internal MOSFETs to
achieve high efficiency and can generate very low output voltage by using internal reference at 0.6V. It operates at a
fixed switching frequency, and uses the slope compensated current mode architecture. This Step-Down DC-DC
Converter supplies 2500mA output current at input voltage range from 2.6V to 5.5V.
Current Mode PWM Control
Slope compensated current mode PWM control provides stable switching and cycle-by-cycle current limit for
excellent load and line responses and protection of the internal main switch (P-CH MOSFET) and synchronous
rectifier (N-CH MOSFET). During normal operation, the internal P-CH MOSFET is turned on for a certain time to
ramp the inductor current at each rising edge of the internal oscillator, and switched off when the peak inductor
current is above the error voltage. The current comparator, ICOMP, limits the peak inductor current. When the main
switch is off, the synchronous rectifier will be turned on immediately and stay on until either the inductor current
starts to reverse, as indicated by the current reversal comparator, IZERO, or the beginning of the next clock cycle.

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
5 of 5
QW-R115-005.c
Similar pages