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Features
• Low Start-up Voltage: 1.0V
• 35μA Quiescent Supply Current in Switch-off
mode
• <1μA Shutdown Current
• 90% Efficiency
• Excellent Load and Line Regulation
Characteristics
• 350mΩ Internal MOSFET
• 450KHz Fixed Switching Frequency
• Small 6-Lead SOT-23 Package
EP4001
High Efficiency, Step-Up Converter with EXT
Description
The EP4001 is a micropower, high efficiency, and
low voltage step-up DC/DC converter intended
for use in battery powered wireless applications.
With the low start-up input voltage below 1V, the
device is suitable for applications with 1 or 2 AA
cells, providing up to 300mA output current at
3.3V output. The 35µA low quiescent current,
zero shutdown current and high efficiency
maintains long battery lifetime. A switching
frequency of 450KHz minimizes solution footprint
by allowing the use of small inductors and
ceramic capacitors. The device is offered in a low
profile (1mm) small 6-lead SOT-23 package.
The current mode PWM design is optimized for
stable and high efficiency operations over a wide
range of load currents. With low resistance
internal MOSFET switches, the EP4001
maintains high efficiency over a wide range of
load current. In addition to its high efficiency at
moderate and heavy loads, the EP4001 includes
automatic PFM operation that improves efficiency
of the power converter at light loads.
Applications
• PDA
• DSC
• LCD Panel
• RF-Tags
• MP3
• Portable Equipment
• Wireless key board and mouse
Typical Application
R2
⎠
Where FB=1.22V
Figure 1-Basic application circuit with EP4001
V
OUT
= FB
×
⎜
1
+
⎛
⎝
R1
⎞
⎟
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Pin Assignment
EP4001
Ordering Information
Pin Description
Pin
1
2
3
4
5
6
Name
EN
EXT
GND
SW
V
IN
FB
Function
Chip enable EP4001 gets into shutdown mode when EN pin set to low
Output pin for driving external NMOS.
Ground.
Pin for switching.
Supply Input Pin. Must be closely decoupled to GND, Pin 2, with a 2.2µF or
greater ceramic capacitor.
Feedback input pin Internal reference voltage for the error amplifier is
1.25V
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Thermal Resistance
(Note 1)
Package
TSOT23-6
θ
JA
220°C/W
θ
JC
EP4001
110°C/W
Absolute Maximum Rating
(Note 2)
Symbol
V
IN
V
SW
I
SW
I
EXT
T
J
T
STG
Item
Input Supply Voltage
SW Pin Switch Voltage
Other I/O Pin Voltage
SW Pin Switch Current
EXT Pin Driver Current
Junction Temperature
(Note 3)
Rating
-0.3 ~ +6
-0.3 ~ +6
-0.3 ~ V
IN
+0.3
2.5
150
+125
-65 ~ +150
Units
V
V
V
A
mA
°C
°C
Storage Temperature Range
Note 1:Thermal
Resistance is specified with approximately 1 square of 1 oz cooper.
Note 2:Absolute
Maximum ratings are threshold limit values that must not be exceeded even for an
instant under any conditions. Moreover, such values for any two items must not be reached
simultaneously. Operation above these absolute maximum ratings may cause degradation
or permanent damage to the device. These are stress ratings only and do not necessarily
imply functional operation below these limits.
Note 3:T
J
is calculated from the ambient temperature T
A
and power dissipation P
D
according to the
following formula: T
J
= T
A
+ (PD)
×
(220°C/W)
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Electrical Characteristics
Symbol
V
S
I
Q
I
Q
I
Q
I
Q
Parameter
Start-up Voltage
Operating V
OUT
Range
Quiescent Current (Shutdown
Current)
Quiescent Current (Switch-off
Current)
Quiescent Current (Continuous
Switching Current)
Quiescent Current (No Load
Current)
T
A
=+25°C
V
FB
F
S
D
MAX
I
LIMIT
Feedback Reference Voltage
Switching Frequency
Maximum Duty
SW ON Resistance
Current Limit Setting
EXT ON Resistance to V
IN
EXT ON Resistance to GND
Output Voltage
Output Voltage
Line Regulation
Load Regulation
Load Regulation
EN Pin Trip Level
Temperature Stability for V
OUT
Thermal Shutdown
Thermal Shutdown Hysteresis
V
IN
=1.5V, I
L
=100mA
-40°C≤T
A
≤
85°C
V
IN
=3.0V, I
L
=300mA
-40°C≤T
A
≤
85°C
V
IN
=1V to 3V, I
L
=1mA
V
IN
=1.5V, I
L
=1mA to
100mA
V
IN
=3.0V, I
L
=1mA to
300mA
0°C≤T
A
≤
85°C
-40°C≤T
A
≤
85°C
1.195
1.190
1.183
380
85
Conditions
I
L
=1mA
V
IN
pin voltage
EN pin = 0V, V
IN
=4.5V
V
IN
=6V
V
IN
=EN=3.3V,
V
FB
=GND
Min.
2
0.01
35
0.4
110
1.220
1.220
1.220
450
90
0.03
2
16
18
3.300
3.300
0.3
0.4
0.4
0.4
0.8
110
165
10
Typ.
0.85
EP4001
(V
IN
= 1.5V, V
OUT
=3.3V, IL = 0mA, T
A
=25°C, Test Circuit Figure 2, unless otherwise specified)
Max.
1.05
4.2
1
50
0.6
Units
V
V
µA
µA
mA
µA
1.245
1.250
1.257
520
1.1
V
V
V
KHz
%
Ω
A
Ω
Ω
V
V
mV/V
mV/mA
mV/mA
1.2
V
ppm/°C
°C
°C
V
OUT
V
OUT
∆V
LINE
∆V
LOAD
∆V
LOAD
T
S
3.200
3.200
3.400
3.400
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Typical Performance Characteristics
(Test Figure 2 above unless otherwise specified)
EP4001
Efficiency (%)
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Supply Current (uA)
Start Up Voltage (V)
Switching Frequency (KHz)
Output Voltage (V)
Efficiency (%)
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