SM8103
High Efficiency, 3.0A, 18V Input
Synchronous Step Down Regulator
SM8103 Rev0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 1
© 2019 Silergy Corp. All Rights Reserved.
General Description
The SM8103 is a high efficiency, 500kHz
synchronous step-down DC/DC regulator capable of
delivering up to 3A load current. It can operate over a
wide input voltage range from 4.2V to 18V and
integrate main switch and synchronous switch with
very low R
DS(ON)
to minimize the conduction loss.
The SM8103 adopts the instant PWM architecture to
achieve fast transient responses for high step down
applications and high efficiency at light loads. In
addition, it operates at pseudo-constant frequency of
500kHz to minimize the size of the inductor and the
capacitor.
Ordering Information
Ordering Number
Package type
Note
SM8103ADC
TSOT23-6
----
Features
Low R
DS(ON)
for Internal Switches (Top/Bottom):
90mΩ/50mΩ
4.2-18V Input Voltage Range
3A Output Current Capability
500kHz Switching Frequency Minimize the
External Components
Stable with 10µF C
OUT
and 2.2µH Inductor
Instant PWM Architecture to Achieve Fast
Transient Responses
Internal Soft-start Limits the Inrush Current
Cycle-by-cycle Peak/Valley Current Limitation
Hic-cup Mode Output Short Circuit Protection
Thermal Shutdown with Auto Recovery
Output Auto Discharge Function
Compact Package: TSOT23-6
Applications
Set Top Box
Portable TV
DSL Modem
LCD TV
IP CAM
Networking
Typical Application
V
OUT
: 3.3V
LX
IN
GND
FB
EN
V
IN
:4.2~18V
C
IN
10uF
L 4.7uH
R
H
100k
C
OUT
10uF
BS
R
L
22.1k
C
BS
100nF
C
FF
100pF
SM8103
Figure1. Schematic Diagram
Inductor and C
OUT
Selection Table
V
OUT
[V]
L
[µH]
C
OUT
[µF]
4.7
10
22
1.2
1.5
√
2.2
☆
3.3
2.2
√
√
4.7
☆
√
5
3.3
√
√
6.8
☆
√
Note: ‘☆’ means recommended for most applications.
Efficiency vs. Load Current
Efficiency (%)
Load Current (A)
0.01 0.1 1 10
60
70
80
90
100
65
75
85
95
V
IN
=12V, V
OUT
=3.3V
V
IN
=18V, V
OUT
=3.3V
V
IN
=5V, V
OUT
=3.3V
Figure2. Efficiency vs. Output Current
Package Code
Temperature Code
Optional Spec Code
□
(
□□
)
Temperature Code
)
□
SM8103
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