SI-8511NVS
■External
Dimensions (TSSOP24)
2.0
φ
Mirror surface
Depth 0.02 to 0.08
A
(Unit : mm)
1.0
φ
Mirror surface
Depth 0.02 to 0.08
5.60±0.1
7.6±0.2
1.90
3.00
(6.4)
1
12
11
°
0.375 TYP
0.65
0.22
+0.1
–0.05
7.80±0.1
7.9±0.2
0.15
–0.05
+0.1
0.12 M
A
0.4
1.15±0.05
11
°
11
°
11
°
11
°
24
13
11
°
11
S
°
0.10±0.05
11
°
Plastic Mold Package Type
Flammability: UL94V-0
Product Mass: Approx. 1.36g
0.50±0.2
0~10
0.08 S
°
■Block
Diagram (Pin Assignment)
V
IN
+
+5V
V
CC
1
ILIM
V
IN
ISEN
V
CC
2
OCP
PRE_REG
EN
H : ON
L : OFF
EN
Vpreg
Level
Shift
VH
Latch
Buff
DRVH
V
O
Synchronous
Cont.
(Logic)
LIN
+
UVLO
Gate Driver
OFF Clamp
POWER_GOOD
H : GOOD
L : NG
PWRGD
Power
Good
–
+
Logic
Buff
DRVL
PGND
Switching
Constant On
Time Cont.
+
COMP
–
V
O
VSNS
–
+
OSC
SS
OVP_SL
GND
FADJ
Open : Change Frequency
Short : 400KHz Operation
FSET
14
SS
12
SKIP
Open : Skip Mode
L
: No Skip Mode
■Typical
Connection Diagram
V
IN
R2
V
CC
: 5V
D2 : SFPL52
C7 : 0.1
µ
F
C1 : 10
µ
F
R1
5mΩ
R5
10Ω
MOS FET Q
1
, Q
2
• Be sure to use logic type MOS FET as Q
1
and Q
2
.
If you use a normal power MOS FET type, the ON resistance may not drop to a
satisfactory level due to a shortage of V
GS
. This may deteriorate the efficiency
and cause overheating.
Diode D
1
• Be sure to use a Schottky-barrier diode for D
1
.
If other diodes like fast recovery diodes are used, IC may be destroyed because
of the reverse voltage generated by the recovery voltage or ON voltage.
Choke coil L
1
• If the winding resistance of the choke coil is too high, the efficiency may drop
below the rated value.
• Take care concerning heat radiation from the choke coil caused by magnetic
saturation due to overload or short-circuit load.
Capacitor C
1
, C
2
• As large ripple currents flow through C
1
and C
2
, use high-frequency and low-
impedance capacitors suitable for switching mode power supplies. Especially
when the impedance of C
2
is high, the switching waveform may become abnor-
mal at low temperatures. For C
2
, do not use a capacitor with an extremely low
equivalent series resistance (ESR) such as a ceramic capacitor, which may cause
an abnormal oscillation.
* To create the optimum operating conditions, place the components as close as
possible to each other.
1
2
3
4
C6
0.1 ~ 1
µ
F
C9
1000
pF
5
6
7
8
V
CC
R7
47kΩ
PWRGD
11
12
R10
2.2kΩ
R9
9
10
NC
DRVH
VH
V
IN
ISEN
ILIN
SI-8511NVS
GND
VSNS
V
O
PWRGD
REF
NC
NC
LIN
DRVL
PGND
V
CC
2
OVP_SL
V
CC
1
SS
EN
SKIP
FADJ
NC
24
23
22
21
20
19
Q2
R6
10Ω
Q1
L1 : 10
µ
H
V
O
+
D1
SJPJ-L3
C2 :
330
µ
F
C5 : 4.7
µ
F
R13
R12
18
C4 : 3.3
µ
F
V
CC
EN
SKIP
R4
47kΩ
C3
0.1
µ
F
17 C8 : 220pF
16
15
14
13
R11 : 100kΩ
R8 : 200kΩ
ICs
83
SANKEN [ SANKEN ELECTRIC ]
