UM3433
600mA, 600kHz Step-Up DC-DC Converter
UM3433
SOT23-6
General Description
The UM3433 is synchronous rectified, fixed frequency, step-up DC/DC converter series
delivering high efficiency in a low profile SOT23-6 package. It is available both in 3.3V/3.0V
fixed output and adjustable output. With an internal NMOS switch and PMOS synchronous
rectifier and high switching frequency of 600KHz, the UM3433 is capable of supplying 3.3V
output at 100mA from a single AA cell input using low profile inductors and ceramic capacitors.
Current mode PWM control with internal compensation cuts external parts count thereby saving
BOM cost and PCB real estate. At light loads, UM3433 enters automatically into power saving
mode to keep high efficiency at light load. Anti-ringing control circuitry inside reduces EMI
interferences by damping the inductor in discontinuous mode.
The device also features low shutdown current of under 1
μA.
With inrush current limiting and
soft start built inside, it also limits the inrush of current during start up, minimizing surge currents
seen by the input supply.
Applications
MP3 Players
Digital Cameras
LCD Bias Supplies
Handheld Instruments
Wireless Handsets
GPS Receivers
Features
Up to 92% efficiency
Low Voltage Start-Up: 0.9V
Inrush current limiting and internal soft
start
Automatic Power-Saving Mode Operation
with typical IQ as 20μA
Short Circuit Protection
600kHz Switching Frequency for low
profile inductor/capacitor
Anti-ringing Control to minimizes EMI
Output range: 2.5V to 5V, with 3.3V/3.0V
fixed output option
Pin Configurations
Top View
(*: only available for adjustable version)
UM3433-3.3 (UCR)
UM3433-3.0 (UDR)
UM3433-ADJ (UCS)
SOT23-6
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UM3433
Pin Description
Pin Number
1
2
3
4
5
6
Symbol
SW
GND
NC(UM3433-3.3/3.0)
FB(UM3433-ADJ)
____________
Description
Switch pin for external inductance
Ground
Not Connect
Feedback input pin
Logic Controlled Shutdown Input
____________
____________
SHDN
VOUT
VIN
SHDN =high, Normal operation mode
SHDN =low, shutdown mode
Output Voltage
Input Voltage
Ordering Information
Part Number
UM3433-3.3
UM3433-3.0
UM3433-ADJ
Packaging Type
SOT23-6
SOT23-6
SOT23-6
Marking Code
UCR
UDR
UCS
Shipping Qty
3000pcs/7Inch
Tape & Reel
3000pcs/7Inch
Tape & Reel
3000pcs/7Inch
Tape & Reel
Absolute Maximum Ratings
Symbol
V
IN
V
SW
V
FB
V
SHDN
V
OUT
T
OP
T
STG
__________
Parameter
V
IN
Supply Voltage
SW Voltage
FB Voltage
SHDN Voltage
Output Voltage
Operating Temperature Range
Storage Temperature Range
____________
Value
-0.3 to +6V
-0.3 to +6V
-0.3 to +6V
-0.3 to +6V
-0.3 to +6V
-40 to +85
-65 to +150
Unit
V
V
V
V
V
°C
°C
T
L
Maximum Lead Temperature (Soldering , 10s)
+300
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings
applied to the device are individual stress limit values (not normal operating conditions) and are
not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
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UM3433
Electrical Characteristics
(V
IN
= +1.2V, V
OUT
= +3.3V T
A
=+25°C, unless otherwise noted.)
Parameter
Test Conditions
Min
Input Voltage Range
Fixed Output Voltage
Output Voltage Adjustable
Range
Feedback Voltage
Quiescent Current
(power-saving mode)
Quiescent Current
(Active)
Quiescent Current
(shutdown)
NMOS Leakage
PMOS Leakage
NMOS On-resistance
PMOS On-resistance
NMOS Current limit
Power-Saving Mode
Operation Current threshold
Current Limit Delay to
Output
Switching Frequency
____________
Typ
3.3
3.0
Max
2.5
3.38
3.08
5
Unit
V
V
V
V
µA
0.9
UM3433-3.3, I
load
=100mA
UM3433-3.0, I
load
=100mA
UM3433-ADJ
3.22
2.92
2.5
1.192
I
load
=0mA
I
load
=100mA
_____________
1.230
20
380
1.268
550
1
µA
µA
µA
µA
Ω
Ω
mA
mA
ns
kHz
V
SHDN =0V
V
SW
=3.3V
0.1
0.1
0.35
0.45
600
850
3
40
L=10µH (Note)
SHDN Input High
____________
____________
I
load
=100mA, SHDN =1V
I
load
=100mA
I
load
=100mA
I
load
=100mA, SHDN =1V
_____________
_____________
600
1
0.35
0.01
1
SHDN Input Low
SHDN Input Current
Note: Design guaranteed.
V
µA
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UM3433
Typical Operating Characteristics
Efficiency vs Output Current
100
98
96
94
Efficiency (%)
92
90
88
86
84
82
80
0
20
40
60
V
IN
=1.3V
V
IN
=1.5V
Efficiency (%)
90
80
70
60
50
40
100
V
OUT
=3.3V
I
OUT
=40mA
Efficiency vs Input Voltage
80
100
0.5
1.0
1.5
Input Voltage (V)
2.0
2.5
Output Current (mA)
Output Voltage vs Temperature
3.44
3.40
3.36
V
OUT
(V)
3.32
3.28
3.24
3.20
V
IN
=1.5V
I
OUT
=30mA
Quiescent Current (uA)
40
Power-Saving Mode Quiescent Current
vs Temperature
V
OUT
=3.3V
35
30
25
20
15
10
-60
-40
-20
0
20
40
60
80
100
-60
-40
-20
0
20
40
60
80
100
Temperature (
℃
)
Temperature (℃)
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UM3433
Typical Operating Characteristics
Fixed Frequency Discontinuous Mode Operation
Fixed Frequency Continuous Mode Operation
Power-Saving Mode Operation
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