1-1-2 Switching Mode Regulator ICs
SI-8511NVS
Surface-Mount, Synchronous Rectifier Step-down Switching Mode Regulator Control ICs
sFeatures
• Surface-mount package (TSSOP24)
• High efficiency due to synchronous rectifica-
tion: 92% (at V
IN
= 5V, I
O
= 1A, V
O
= 2.5V)
• Capable of downsize a choke-coil due to IC's
high switching frequency (400kHz typ, On
Time Control). (Compared with conventional
Sanken devices)
• Low reference voltage (V
ref
) 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%
sAbsolute
Maximum Ratings
Parameter
Control-System DC Input Voltage
DC Input Voltage
Boost Block Input Voltage
EN Terminal Input Voltage
PWRGD Terminal Applied Voltage
Junction Temperature
Storage Temperature
Symbol
V
CC
V
IN
V
H
V
EN
V
PWRGD
T
j
T
stg
Ratings
7
25
30
V
CC
7
+150
–40 to +150
Unit
V
V
V
V
V
°C
°C
(T
a
=25°C)
sApplications
• 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
sRecommended
Operating Conditions
Parameter
Control System Input Voltage Range
Input Voltage Range
Output Voltage Range
Operating Temperature Range
Symbol
V
CC
V
IN
V
O
T
op
Ratings
4.5 to 5.5
3 to 18
1.1 to 6
–20 to +85
Unit
V
V
V
°C
sElectrical
Characteristics
Parameter
Dynamic
Output Voltage
Characteristics Temperature Coefficient of Output Voltage
Circuit Current (V
CC
Terminal)
Circuit
Current
Circuit Current (V
IN
Terminal)
Standby Current 1 (V
CC
Terminal)
Standby Current 2 (V
IN
Terminal)
Undervoltage UVLO Operating Voltage 1 (V
CC
Terminal)
Lockout
UVLO Operating Voltage 2 (V
IN
Terminal)
On Time
On Time
Control
High Side
Drive
Low Side
Drive
Bootstrap
Minimum Off Time
REF Terminal Voltage
REF Terminal Source Current
On Resistance (high side)
On Resistance (low side)
On Resistance (high side)
On Resistance (low side)
Bootstrap Voltage
Current for Current Limit Detection
Soft Start Terminal Current
EN Low Level Voltage
EN High Level Voltage
Protection
System
EN Bias Level Current
PWRGD Good Voltage (high side)
PWRGD Good Voltage (low side)
PWRGD Low Output Voltage
PWRGD Terminal Current
PWRGD Leakage Current
Symbol
V
O
∆V
O
/∆T
I
op
I
op
I
std1
I
std2
V
uvlo1
V
uvlo2
T
on
T
off
V
ref
I
ref
RonHH
RonHL
RonLH
RonLL
VH-VLIN
I
lim
I
ss
V
celo
V
cehi
ICE
V
sens
V
sens
V
pwrgd
I
pwrgd
I
pwrgd
1.32
0.88
0.4
120
5
0
2.4
4.5
90
5.5
5.5
5.5
5.5
5
100
±20
0.8
V
CC
5
5.5
110
1.1
3.7
2.5
1.27
0.7
1.2
1.3
100
Ratings
min.
–1.2%
typ.
1.1
±0.03
6
1
100
50
4.45
2.9
max.
+1.2%
Unit
V
mV/°C
mA
mA
(T
a
=25°C unless otherwise specified)
Conditions
V
IN
=5V, V
CC
=5V, VSNS connected to VO, I
O
=0A
V
IN
=5V, V
CC
=5V, VSNS connected to VO, I
O
=0A, T
a
=0 to 85°C
V
CC
=5V, EN=H, FADJ:open
V
IN
=5V, EN=H
V
CC
=5V, EN=L
V
IN
=5V, EN=L
V
IN
=5V
V
CC
=5V
V
CC
=5V, V
IN
=5V, V
O
=2.5V
V
CC
=5V
V
CC
=5V
V
CC
=5V
VH-VLIN=5V
VH-VLIN=5V
V
CC
=5V
V
CC
=5V
V
CC
=5V, V
IN
=5V
V
CC
=5V
V
CC
=5V
V
CC
=5V
V
CC
=5V, EN=5V
V
CC
=5V
V
CC
=5V
V
CC
=5V, Ipwrgd=120
µ
A
V
CC
=5V, Vpwrgd=0.4V
Vpwrgd=5V
µ
A
µ
A
V
V
µ
S
µ
S
V
µ
A
V
µ
A
µ
A
V
V
µ
A
V
V
V
µ
A
µ
A
74
ICs
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