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Número de pieza | EML3171 | |
Descripción | Synchronous Step-Down DC-DC Converter | |
Fabricantes | Elite Semiconductor | |
Logotipo | ||
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EML3171
2.0A, Synchronous Step-Down DC-DC Converter
General Description
EML3171 is a high efficiency, DC-DC synchronous
buck converter which provides 2.0A output loading
after output voltage reach preset voltage. EML3171
uses different modulation algorithms for various
loading conditions. Under heavy load, EML3171
regulates the output voltage using Pulse Width
Modulation (PWM). The PWM mode provides low
output voltage ripple and fixed frequency noise.
While in light load, it enters Power Skip Modulation
(PSM) automatically to ensure a highly efficient
operation at light load condition. Under very heavy
load condition or when the input voltage
approaches the output voltage, EML3171 enters low
dropout voltage operation under 100% duty cycle.
The internal generated 0.8V precision feedback
reference voltage is designed for low output voltage
request. Low Power-FET Ron synchronous switch
dramatically reduces conduction loss.
The EML3171 is available in an 8-pin, space-saving
TDFN-3x3 package.
Typical Application
Features
Wide Operating Voltage Ranges : 2.6V to 5.5V
2.0A Output Current
High efficiency Buck Power Converter
Auto-select PSM/PWM
LDO mode: duty cycle: 100%
Synchronous Power Switches Rectification, no
Schottky Diode Required
1.4MHz Switching Frequency
Internal Soft-Start
Current Limit Protection
Over Temperature Protection
Output Shorting Protect
Output Over Voltage Protection
Applications
Cellular telephone
Wireless and DSL Modems
Digital Still Cameras
Portable Products
MP3 Players
R
V = V × (1 + 1 )
OUT
FB
R
2
Fig. 1 EML3171 application circuit
Elite Semiconductor Memory Technology Inc.
Publication Date: Dec. 2013
Revision: 0.1
1/16
1 page ESMT
EML3171
Typical Performance Characteristics
VIN=5.0V, TA=25℃, L=2.2uH, CIN=22uF, COUT=22uF,unless otherwise specified
Efficiency vs. Load (Fig. 3)
Efficiency vs. Load (Fig. 4)
100
90
80
70
60
50
40
30
20
10
0
1
VI=5.0V
VI=3.6V
VI=4.2V
VO=3.3V
10 100 1000
Output Current (mA)
10000
100
90
80
70
60
50
40
30
20
10
0
1
VI=2.5V
VI=3.6V
10
VI=4.2V
VI=5.0V
100
Output Current (mA)
V0=1.2V
1000 10000
Load Regulation (Fig. 5)
Load Regulation (Fig. 6)
3.36
3.34
VI=5.0V
3.32
VI=5.5V
3.30
3.28
3.26
3.24
1
VI=3.6V
VO=3.3V
10 100 1000
Output Current (mA)
10000
Quiescent Current vs. Input Voltage (Fig. 7)
1.24
1.22 VI=3.6V
1.20
1.18
1.16
1.14
1
VI=2.5V
VI=5.0V
VO=1.2V
10 100 1000
Output Current (mA)
10000
Quiescent Current vs. Temperature (Fig. 8)
300
250
Quiescent Current
200
150
100
50 T=25℃
VFB=0.9V
0
2.5 3.0 3.5 4.0 4.5 5.0 5.5
Input Voltage (V)
300
250 Quiescent Current
200
150
100
50
VI=5.0V
VFB=0.7V
0
-40 -15 10 35 60 85
Temperature (℃)
Elite Semiconductor Memory Technology Inc.
Publication Date: Dec. 2013
Revision: 0.1
5/16
5 Page ESMT
EML3171
Output Voltage Setting
The output voltage of EML3171 can be adjusted by a resistive divider according to the following formula:
VOUT
= VREF
* ⎜⎜⎝⎛1 +
R1
R2
⎟⎟⎠⎞ = 0.8*⎜⎜⎝⎛1+
R1
R2
⎟⎟⎠⎞
The resistive divider senses the fraction of the output voltage as shown in Fig.21 Using large feedback resistor
can increase efficiency, but too large value affects the device’s output accuracy because of leakage current
going into device’s FB pin. The recommended value for R2 is therefore in the range of 50KΩ.
VOUT
FB
EML3171
R1
R2
Fig. 21 Setting the Output Voltage
Under Voltage Lock Out
The under-voltage lockout (UVLO) circuitry ensures that the EMl3171 starts up with adequate voltage. The
regulator output is disabled whenever VIN is below UVLO. The hysteresis of UVLO is designed to be 100 mV.
Elite Semiconductor Memory Technology Inc.
Publication Date: Dec. 2013
Revision: 0.1
11/16
11 Page |
Páginas | Total 16 Páginas | |
PDF Descargar | [ Datasheet EML3171.PDF ] |
Número de pieza | Descripción | Fabricantes |
EML3170 | Synchronous Step-Down Regulator | Elite Semiconductor |
EML3171 | Synchronous Step-Down DC-DC Converter | EML3171-EliteSemiconductor.pdf |
EML3171 | Synchronous Step-Down DC-DC Converter | Elite Semiconductor |
EML3172 | Synchronous Step-Down DC-DC Converter | EML3172-EliteSemiconductor.pdf |
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