ELM611DA 2A 23V
high efficiency synchronous PWM step down DC/DC converter
■Pin configuration
SOP-8(TOP VIEW)
Pin No.
Pin name
BS
VIN
SW
GND
FB
COMP
EN
SS
Pin description
High-side gate drive boost input
Power input
Power switching output
Ground
Feedback input
Compensation node
Enable input
1
2
3
4
5
6
7
8
1
8
7
6
5
2
3
4
Soft start control input
■Standard circuit
Input
2
1
C3=10nF
R4=22kΩ
L=10µH
Cin=
10µF/25V
Ceramic
VIN
BS
7
8
3
Output=
3.3V/2A
EN
SW
FB
C5=
ELM611DA
0.1µF
R1=26.1kΩ
1%
5
R5=
10kΩ
SS
GND
COMP
Cout=
22µF/6.3V
Ceramic×2
4
6
R2=10kΩ
1%
C1=3.3nF
C2=
0.1µF
C4
Option
R3=2.2kΩ
Note: EN is 5V logic input. When Vin=12V, R4=22kΩ, R5=10kΩ is required; value of R5/R4= 1/2.2
■Block diagram
OVP
2
+
-
VIN
BS
Current sense
amplifier
5V
1.1V
0.3V
RAMP
CLK
+
-
Oscillator
100kHz &
350kHz
5
8
FB
SS
+
-
1
M1
-
+
+
S
Q
Q
85mΩ
Error
amplifier
-
+
3
4
SW
R
0.923V
M2
6µA
Current
comparator
85mΩ
OVP
GND
EN
IN<4.10V
IN
6
7
COMP
EN
1.2V
5V
Internal
-
+
regulators
Shutdown
comparator
1.5V
Rev.1.2
11 - 2
ELM-TECH [ ELM Technology Corporation ]
