ME2139
ULTRA-SMALL PACKAGE
PWM/PFM
SWITCHING CONTROL
STEP-UP SWITCHING REGULATOR
General Description
The ME2139 series is a CMOS step-up
switching regulator which mainly consists of a
reference voltage source, an oscillation circuit,
an error amplifier, a phase compensation circuit,
a PWM/PFM switching control circuit. With an
external low-ON-resistance Nch Power MOS,
this product is applicable to applications requiring
high efficiency and high output current. The
ME2139 series switches its operation to the PFM
control circuit whose duty ratio is 15 % with to the
PWM/PFM switching control circuit under a light
load and to prevent decline in the efficiency by IC
operation current.
Features
Low voltage operation: Start-up is guaranteed from
0.9 V(IOUT =1 mA )
Duty ratio: Built-in PWM/PFM switching control
circuit 15 to 78 % .
oscillator frequency:1.0MHz
External parts: coil, diode, capacitor, and transistor
Output voltage range:<20V
Feedback voltage accuracy:±
2%
Soft start function: 2 ms
Applications
MP3 players, digital audio players
Digital cameras, GPS, wireless transceiver
Portable devices
Package
● 5-pin SOT23-5
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ME2139
Electrical Characteristics
ME2139FxxG
Measuring conditions:VDD=VCE=3.3V,Topt=25℃。Unless otherwise specified。
Parameter
Feedback voltage
Input voltage
Operation start
voltage
Operation holding
voltage
Current consumption 1
Current consumption 2
SYMBOL
V
FB
V
IN
V
ST
V
HLD
I
SS1
I
SS2
I
SSS
I
EXTH
I
EXTL
I
OUT
=1mA
CONDITION
-
-
MIN
1.225
TYP
1.25
-
MAX
1.275
6
0.9
-
-
-
0.5
-
-
-
1.2
-
-
-
0.3
0.2
0.1
0.1
-
-
UNIT Circuit
V
V
V
V
μA
μA
μA
mA
mA
ppm/℃
2
2
2
2
1
1
1
1
1
2
1
1
1
1
1
1
1
1
2
2
-
0.7
-
-
-
-
-
-
-
-
-
200
15
0.02
-25
40
±
50
1.0
78
15
-
-
-
-
-
2
90
I
OUT
=1mA
,
Measured by decreasing VIN
voltage gradually
V
FB
=V
FB
(S)× 0.95
V
FB
=1.5V
V
CE
=0V
V
EXT
=V
OUT
-0.4V
V
EXT
=0.4V
Current consumption
during shutdown
EXT pin output
current
Feed back
voltagetemperature
coefficient
Oscillation frequency
Max. duty ratio
PWM/PFM
switchingduty ratio
Shutdown pin input
voltage
Ta=-25-85℃
Fosc
MAXDUTY V
FB
=V
FB
(S)× 0.95
0.8
-
-
0.75
-
-
-0.1
-0.1
MHz
﹪
﹪
V
V
V
μA
μA
mS
﹪
PFMDUTY V
FB
=V
FB
(S)× 1.5, no load
V
SH
V
SL1
V
SL2
Shutdown pin input
voltage
Soft start time
Efficiency
1.
2.
3.
4.
Measured the oscillation at EXT pin
Judged the stop of
oscillation at EXT pin
V
CE
=V
FB
(S)×0.95
V
CE
=0V
-
-
V
OUT
≥1.5V
V
OUT
<1.5V
I
SH
I
SL
tss
EFFI
-
-
VOUT(S) is the set output voltage value,and VOUT is the typital value of the output voltage.
VOUT(S) can be set by using the rate of VFB and output voltage setting resisitors(R1,R2).
VFB(S) is the set output voltage value.
This product from the start when the VDD=0.9V booster work , but in order to stabilize the output voltage and oscillation
frequency ,to control the VDD, 2.5V≦VDD<6V.
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Page 5 of 12