1-1-3 DC/DC Converter ICs
NR887D
Current Mode Control, Synchronous Rectifier Step-down Switching Mode
Full-Mold, Separate Excitation Step-down Switching Mode Regulator ICs
■Features
•
DIP 8 pin package
•
Input voltage range (V
IN
): V
O
+ 3 to 18 V
•
Synchronous rectifier mode
•
High efficiency: 90%
•
Introduction of current mode control method
•
•
•
•
•
•
•
•
A ceramic capacitor can be used for output
Built-in phase correction component
Output current: 2 A
Reference voltage and accuracy of 0.8 V
±
2%
Oscillation frequency: 500 kHz
Output ON/OFF available
Undervoltage lockout
Soft start function
Parameter
■Absolute
Maximum Ratings
Parameter
Symbol
Ratings
Unit
Conditions
Input Voltage
Power Dissipation
Junction Temperature
Storage Temperature
Thermal Resistance (Junction to Lead (4 pins))
Thermal Resistance (Junction to Ambient Air)
V
IN
P
D
T
j
T
stg
θ
j-c
θ
j-a
20
1.50
–40 to +150
–40 to +150
25
67
V
W
°C
°C
°C/W
°C/W
When mounted on a 70
×
60 mm glass-epoxy board (with a 1310 mm
2
copper area)
When mounted on a 70
×
60 mm glass-epoxy board (with a 1310 mm
2
copper area)
■Recommended
Operating Conditions
Input Voltage Range
Output Current Range
Output Voltage Range
Operating Temperature Range
Symbol
V
IN
I
o
V
o
T
op
Ratings
4.5 or V
O
+ 3* to 18
0
to
2.0
0.8 to 14
–40 to +85
Unit
V
A
V
°C
*: The minimum value of the input voltage range is 4.5 V or V
O
+ 3 V, whichever is higher.
■Applications
•
•
•
•
Power supply for LCDTV and PDP
Power supply for DVD, BD, and STB
On-board local power supply
Power supply for switches
■Electrical
Characteristics
Parameter
Reference Voltage
Temperature Coefficient of Reference Voltage
Efficiency
Oscillation Frequency
Line Regulation
Load Regulation
Overcurrent Protection Starting Current
Quiescent Circuit Current 1
Quiescent Circuit Current 2
Outflow Current at Low Voltage
SS Pin
Open Voltage
Inflow Current
EN Pin
On Threshold Voltage
Maximum ON Duty
Minimum ON Time
Thermal Protection Start Temperature
Thermal Protection Return Hysteresis
Symbol
V
REF
⊿V
REF
/⊿T
η
(Ta=25°C, V
IN
=12V, V
O
=3.3V, and Io=1.0A, unless otherwise specified)
min.
0.784
fo
V
LINE
V
Load
I
s
I
IN
I
IN(off)
I
EN/SS
V
SSH
I
EN
V
C/EH
DMAX
DMIN
TSD
TSD_hys
400
Ratings
typ.
0.800
±0.05
90
500
50
50
6
max.
0.816
Unit
V
mV/℃
%
kHz
mV
mV
A
mA
µA
µA
V
µA
V
%
nsec
℃
℃
Ta=–40℃ to +85℃
Conditions
600
V
IN
=6.3V to 18V
I
o
=0.1 to 2.0A
V
EN
=10Ω pull up to V
IN
I
o
=0A, V
EN
=0V
V
SS
=0V
V
EN
=10V
3.1
6.0
10
14
100
2.1
6
0.7
151
10
3.0
50
1.4
90
150
165
20
*: Pin 8 is the SS pin. Soft start at power on can be performed with a capacitor connected to this pin.
The SS pin is pulled up to the power supply in the IC, so applying the external voltage is prohibited.
NR887D
8
SS
C9
Soft start
44
ICs
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