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Features
(Preliminary)
EP3102
150 KHz, 2A Asynchronous Step-down Converter
Description
The EP3102 is a monolithic integrated circuit that
provide all the active functions for a step-down
switching regulator, capable of driving a 2A load
without
additional
transistor
component.
Requiring a minimum number of external
component, the board space can be saved easily.
The external shutdown function can be controlled
by TTL logic level and then come into standby
mode. The internal compensation makes
feedback control have good line and load
regulation without external design. Regarding
protected function, thermal shutdown is to
prevent over temperature operating from damage,
and current limit is against over current operating
of the output switch. The EP3102 operates at a
switching frequency of 150KHz thus allowing
smaller sized filter components than what would
be needed with lower frequency switching
regulators. Other features include a guaranteed
+4% tolerance on output voltage under specified
input voltage and output load conditions, and
+15% on the oscillator frequency. The output
version included fixed 3.3V, 5V, 12V, and an
adjustable type. The package is available in a
standard 8-lead SOP8.
• 3.3V, 5V, 12V and Adjustable Output Version
• Adjustable Version Output Voltage Range,
1.23V to 37V +4% Max over Line and Load
Condition
• Input Voltage Range up to 40V
• Output Load Current: 2A
• 150 KHz Fixed Frequency Internal Oscillator
• Voltage Mode Non-synchronous PWM Control
• Thermal-shutdown and Current-limit Protection
• ON/OFF Shutdown Control Input
• Low Power Standby Mode
• Built-in Switching Transistor on Chip
• SOP-8L package
Applications
• Simple High-efficiency Step-down (Buck)
Regulator
• Efficient Pre-regulator for Linear Regulators
• On-card Switching Regulators
• Positive to Negative Converter
• Battery Charger
Typical Application
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Pin Assignment
EP3102
Ordering Information
EP3102 - X X X
Buck Regulator
Package
S : SOP-8L
V
OUT
Blank: Adj
33 = 3.3V
50 = 5.0V
12 = 12V
Packing
R: Taping & Reel
B: Bag
Pin Description
Pin
1
Name
V
IN
Function
This is the positive input supply for the IC switching regulator. A suitable
input bypass capacitor must be present at this pin to minimize voltage
transients and to supply the switching currents needed by the regulator.
Internal switch. The voltage at this pin switches between (+V
IN
-V
SAT
) and
approximately-0.5V, with a duty cycle of approximately V
OUT
/V
IN
. To
minimize coupling to sensitive circuitry, the PC board copper area
connected to this pin should be kept a minimum.
Senses the regulated output voltage to complete the feedback loop.
Low enable. Allows the switching regulator circuit to be shutdown using
logic level signals thus dropping the total input supply current to
approximately 150uA. Pulling this pin below a threshold voltage of
approximately 1.3V turns the regulator on, and pulling this pin above
1.3V (up to a maximum of 40V) shuts the regulator down. If this
shutdown feature is not needed, the
EN
pin can be wired to the ground
pin or it can be left open, in either case the regulator will be in the ON
condition.
Circuit ground.
2
SW
3
FB
4
EN
5~8
GND
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Absolute Maximum Rating
(Note 1)
Symbol
V
IN
V
EN
V
FB
V
OUT
V
OP
P
D
T
OP
T
STG
Item
Input Supply Voltage
Rating
+45
-0.3 ~ +25
EP3102
Units
V
V
EN
Pin Input Voltage
Feedback Pin Voltage
Output Voltage to Ground
Operating Voltage
Power Dissipation
Operating Temperature Range
Storage Temperature Range
-0.3 ~ +25
-1
+4.5 ~+25
Internally Limited
-40 ~ +125
-65 ~ +150
V
V
V
W
°C
°C
Electrical Characteristics (All Output Voltage Versions)
(Note 2)
Unless otherwise specified, V
IN
=12V for 3.3V, 5V, adjustable version and V
IN
=24V for the 12V version.
I
LOAD
=0.2A
Symbol
I
FB
F
OSC
F
SCP
V
SAT
DC
I
CL
Parameter
Feedback Bias Current
Oscillator Frequency
Oscillator Frequency of Short
Circuit Protect
Saturation Voltage
Max. Duty Cycle (ON)
Min. Duty Cycle (OFF)
Current Limit
Output=0
Output=-1
I
Q
I
STBY
V
IL
V
IH
I
H
I
L
T
S
Output Leakage
Current
When current limit occurred
and V
FB
<0.55V
I
OUT
=1.5A
no outside circuit V
FB
=0V
force driver on
V
FB
=0V force driver on
V
FB
=12V force driver off
Peak Current
no outside circuit V
FB
=0V
force driver on
No outside circuit V
FB
=12V
fore driver off
V
IN
=24V
V
FB
=12V force driver off
-5
5
70
1.3
10
150
200
0.6
-0.01
-0.1
175
150
15
70
-1
Conditions
V
FB
=1.3V
(Adjustable version only)
127
110
Min.
Typ.
-10
150
Max.
-50
-100
173
173
70
1.4
1.5
Units
nA
KHz
KHz
V
%
3.3
3.6
-200
A
µA
mA
mA
µA
V
µA
µA
°C
°C
°C/W
°C/W
30
1.25
100
0
2.4
2.8
I
L
Quiescent Current
Standby Quiescent Current
EN
pin=5V
V
IN
=24V
Low (regulator ON)
High (regulator OFF)
V
LOGIC
=2.5V (OFF)
V
LOGIC
=0.5V (ON)
T
J
increasing
T
J
decreasing
2.0
EN
Pin Logic Input Threshold
Voltage
EN
Pin Logic Input Current
EN
Pin Input Current
Over Temperature Shutdown
Threshold
Thermal Resistance
Thermal Resistance with
Copper Area of Approximately
3in
2
θ
JC
θ
JA
SOP-8L
SOP-8L
Junction to Case
Junction to
Ambient
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