SI-8511NVS_11 [SANKEN]
Surface-Mount, Synchronous Rectifier Step-down Switching Mode Control ICs; 表面贴装,同步整流降压开关模式控制IC型号: | SI-8511NVS_11 |
厂家: | SANKEN ELECTRIC |
描述: | Surface-Mount, Synchronous Rectifier Step-down Switching Mode Control ICs |
文件: | 总2页 (文件大小:80K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
1-1-3 DC/DC Converter ICs
SI-8511NVS Surface-Mount, Synchronous Rectifier Step-down Switching Mode Control ICs
■Features
■Absolute Maximum Ratings
(Ta=25°C)
• Surface-mount package (TSSOP24)
Parameter
Control-System DC Input Voltage
DC Input Voltage
Symbol
Ratings
Unit
V
VCC
7
• High efficiency due to synchronous rectifica-
tion: 92% (at VIN = 5V, IO = 1A, VO = 2.5V)
VIN
25
V
Boost Block Input Voltage
EN Terminal Input Voltage
PWRGD Terminal Applied Voltage
Junction Temperature
VH
30
VCC
V
• Capable of downsize a choke-coil due to IC's
high switching frequency (400kHz typ, On
Time Control). (Compared with conventional
Sanken devices)
VEN
V
VPWRGD
Tj
7
V
+150
°C
°C
Storage Temperature
Tstg
–40 to +150
• Low reference voltage (Vref) of 1.1V. The
output voltage is variable from 1.1V to 6V.
• High-speed response to a load
• Compatible with low ESR capacitors
• Soft start and output ON/OFF available
• Built-in overcurrent and output-overvoltage
protection circuits
• PWRGD function to indicate the output voltage
status
• High precision reference voltage: 1.1V ± 1.2%
■Applications
• Power supplies for notebook PCs and mobile devices
• Onboard local power supplies
• OA equipment
• For stabilization of the secondary-side output voltage of switching power supplies
■Recommended Operating Conditions
Parameter
Control System Input Voltage Range
Input Voltage Range
Symbol
VCC
VIN
Ratings
Unit
V
4.5 to 5.5
3 to 18
V
Output Voltage Range
VO
1.1 to 6
V
Operating Temperature Range
Top
–20 to +85
°C
■Electrical Characteristics
(Ta=25°C unless otherwise specified)
Ratings
typ.
Parameter
Symbol
Unit
Conditions
min.
max.
Dynamic
Characteristics
Output Voltage
VO
∆VO/∆T
Iop
–1.2%
1.1
+1.2%
V
mV/°C
mA
mA
µA
µA
V
VIN=5V, VCC=5V, VSNS connected to VO, IO=0A
IN=5V, VCC=5V, VSNS connected to VO, I =0A, T =0 to 85°C
Temperature Coefficient of Output Voltage
Circuit Current (VCC Terminal)
Circuit Current (VIN Terminal)
Standby Current 1 (VCC Terminal)
Standby Current 2 (VIN Terminal)
±0.03
V
O
a
6
1
VCC=5V, EN=H, FADJ:open
VIN=5V, EN=H
VCC=5V, EN=L
VIN=5V, EN=L
VIN=5V
Circuit
Current
Iop
Istd1
100
50
Istd2
Undervoltage UVLO Operating Voltage 1 (VCC Terminal)
Lockout
Vuvlo1
Vuvlo2
Ton
3.7
2.5
4.45
2.9
UVLO Operating Voltage 2 (VIN Terminal)
On Time
V
VCC=5V
1.27
0.7
µS
µS
V
VCC=5V, VIN=5V, VO=2.5V
VCC=5V
On Time
Control
Minimum Off Time
Toff
REF Terminal Voltage
Vref
1.1
1.2
1.3
VCC=5V
REF Terminal Source Current
On Resistance (high side)
On Resistance (low side)
On Resistance (high side)
On Resistance (low side)
Bootstrap Voltage
Iref
100
µA
Ω
VCC=5V
High Side
Drive
RonHH
RonHL
RonLH
RonLL
VH-VLIN
Ilim
5.5
5.5
5.5
5.5
5
VH-VLIN=5V
VH-VLIN=5V
VCC=5V
Ω
Low Side
Drive
Ω
Ω
VCC=5V
Bootstrap
4.5
90
5.5
V
Current for Current Limit Detection
Soft Start Terminal Current
EN Low Level Voltage
100
±20
110
µA
µA
V
VCC=5V, VIN=5V
VCC=5V
Iss
Vcelo
Vcehi
ICE
0
0.8
VCC
5
VCC=5V
EN High Level Voltage
2.4
V
VCC=5V
Protection
System
EN Bias Level Current
µA
V
VCC=5V, EN=5V
VCC=5V
PWRGD Good Voltage (high side)
PWRGD Good Voltage (low side)
PWRGD Low Output Voltage
PWRGD Terminal Current
PWRGD Leakage Current
Vsens
Vsens
Vpwrgd
Ipwrgd
Ipwrgd
1.32
0.88
V
VCC=5V
0.4
120
5
V
VCC=5V, Ipwrgd=120µA
VCC=5V, Vpwrgd=0.4V
Vpwrgd=5V
µA
µA
ICs
62
SI-8511NVS
■External Dimensions (TSSOP24)
(Unit : mm)
2.0
φ
Mirror surface
Depth 0.02 to 0.08
A
°
11
24
13
°
11
1.0
φ
Mirror surface
Depth 0.02 to 0.08
3.00
°
11
1
12
°
11
0.65
0.375 TYP
+0.1
0.22
–0.05
0.12
M
A
7.80±0.1
7.9±0.2
0.4
Plastic Mold Package Type
Flammability: UL94V-0
S
Product Mass: Approx. 1.36g
0.50±0.2
0.08
S
■Block Diagram (Pin Assignment)
VIN
+
+5V
V
CC
1
ILIM
V
IN ISEN
VCC2
OCP
PRE_REG
Vpreg
VH
EN
Level
Shift
EN
Latch
Buff
H : ON
: OFF
UVLO
Gate Driver
OFF Clamp
DRVH
LIN
L
VO
Synchronous
Cont.
(Logic)
+
Logic
Buff
POWER_GOOD
H : GOOD
Power
Good
DRVL
PGND
PWRGD
L
: NG
–
+
Switching
VO
Constant On
Time Cont.
VSNS
+
COMP
–
–
+
OSC
SS
GND
OVP_SL
14
12
FADJ
FSET
SS
SKIP
Open : Change Frequency
Short : 400KHz Operation
Open : Skip Mode
: No Skip Mode
L
■Typical Connection Diagram
MOS FET Q1, Q2
• Be sure to use logic type MOS FET as Q1 and Q2.
V
IN
R2
µ
C1 : 10
F
V
CC : 5V
If you use a normal power MOS FET type, the ON resistance may not drop to a
satisfactory level due to a shortage of VGS. This may deteriorate the efficiency
and cause overheating.
µ
C7 : 0.1 F
D2 : SFPL52
R1
5mΩ
R5
10Ω
Diode D1
Q1
• Be sure to use a Schottky-barrier diode for D1.
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.
1
24
NC
NC
LIN
µ
L1 : 10
H
2
23
22
21
20
19
18
17
16
15
14
13
DRVH
V
O
+
Q2
3
C2 :
VH
DRVL
PGND
D1
µ
330
F
R6
10Ω
Choke coil L1
SJPJ-L3
4
V
IN
• 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.
C9
1000
pF
C6
0.1 ~ 1
5
6
R13
µ
C5 : 4.7
F
ISEN
ILIN
VCC2
µ
F
OVP_SL
R12
F
SI-8511NVS
7
µ
C4 : 3.3
C8 : 220pF
GND
VSNS
VCC1
V
CC
Capacitor C1, C2
8
SS
EN
R4
47kΩ
EN
• As large ripple currents flow through C1 and C2, use high-frequency and low-
impedance capacitors suitable for switching mode power supplies. Especially
when the impedance of C2 is high, the switching waveform may become abnor-
mal at low temperatures. For C2, do not use a capacitor with an extremely low
equivalent series resistance (ESR) such as a ceramic capacitor, which may cause
an abnormal oscillation.
V
R7
47kΩ
CC
R9
R10
2.2kΩ
9
V
O
C3
0.1
SKIP
10
11
12
µ
F
PWRGD
REF
SKIP
FADJ
NC
PWRGD
NC
R11 : 100kΩ
* To create the optimum operating conditions, place the components as close as
possible to each other.
R8 : 200kΩ
ICs
63
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