1-1-3 DC/DC Converter ICs
NR885K Surface
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■Features
■Absolute Maximum Ratings
Parameter
Input Voltage
Symbol
VIN
PD
Ratings
20
Unit
V
Conditions
• Compact surface-mount package (HSOP8)
• Input voltage range (VIN): VO + 3 to 18 V
• Synchronous rectifier mode
1.69
W
When mounted on 30 × 30 mm glass-epoxy board (with a 25 × 25 mm copper area)
Power Dissipation
Junction Temperature
Tj
–40 to +150
°C
• High efficiency of at least 94%
Storage Temperature
Tstg
θj-c
–40 to +150
°C
Thermal Resistance (Junction to Lead (4 pins))
Thermal Resistance (Junction to Ambient Air)
40
74
°C/W
°C/W
• Introduction of current mode control method
• A ceramic capacitor can be used for output
• Built-in phase correction component
• Output current: 3 A
θj-a
When mounted on a 30 × 30 mm glass-epoxy board (with a 25 × 25 mm copper area)
■Recommended Operating Conditions
• Reference voltage and accuracy of 0.8 V ± 2%
• Oscillation frequency: 350 kHz
• Output ON/OFF available
Parameter
Symbol
VIN
Ratings
Unit
V
Input Voltage Range
4.5 or VO + 3* to 18
0 to 3.0
Output Current Range
Output Voltage Range
Operating Temperature Range
Io
A
Vo
0.8 to 14
V
• Undervoltage lockout
Top
–40 to +85
°C
• Soft start function
*: The minimum value of the input voltage range is 4.5 V or VO + 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 LBP and PPC
■Electrical Characteristics
(Ta=25°C, VIN=12V, and VO=3.3V, unless otherwise specified)
Ratings
typ.
Parameter
Symbol
Unit
Conditions
min.
max.
Reference Voltage
VREF
⊿VREF/⊿T
η
0.784
0.800
0.05
90
0.816
V
mV/℃
%
VIN=12V，Io=1.0A
Temperature Coefficient of Reference Voltage
Efficiency
VIN=12V，Io=1.0AꢀTa=–40℃ to +85℃
VIN=12V, Vo=3.3V, Io=1A
VIN=12V, Vo=3.3V, Io=1A
VIN=12V, Vo=3.3V, Io=1A
VIN=6.3V to 18V, Vo=3.3V, Io=1A
VIN=12V, Vo=3.3V
Oscillation Frequency
Line Regulation
fo
280
350
50
420
6.0
kHz
mV
mV
A
VLINE
VLoad
Is
Load Regulation
50
Overcurrent Protection Starting Current
Quiescent Circuit Current 1
Quiescent Circuit Current 2
3.1
IIN
6
mA
µA
µA
V
VIN=12V, VEN=3V
IIN(off)
IEN/SS
VSSH
IEN
0
6
10
14
VIN=12V, Io=0A, VEN=0V
VSS=0V, VIN=12V
VIN=12V
Outflow Current at Low Voltage
SS Pin
10
3.0
50
Open Voltage
Inflow Current
100
2.1
µA
V
VEN=10V
VIN=12V
EN Pin
On Threshold Voltage
VC/EH
DMAX
DMIN
TSD
0.7
1.4
90
Maximum ON Duty
%
Minimum ON Time
150
165
20
nsec
℃
℃
Thermal Protection Start Temperature
Thermal Protection Return Hysteresis
151
TSD_hys
*: 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.
NR885K
8
SS
C9
ꢀSoft start
ICs
52
ETC [ ETC ]
