|
ROHM Semiconductor |
TECHNICAL NOTE
High-performance Regulator IC Series for PCs
Ultra Low Dropout
Linear Regulators for PC Chipsets
BD3508EKN
● Description
The BD3508EKN ultra low-dropout linear chipset regulator operates from a very low input supply, and offers ideal
performance in low input voltage to low output voltage applications. It incorporates a built-in N-MOSFET power transistor to
minimize the input-to-output voltage differential to the ON resistance (RON=65mΩ) level. By lowering the dropout voltage in
this way, the regulator realizes high current output (Iomax=3.0A) with reduced conversion loss, and thereby obviates the
switching regulator and its power transistor, choke coil, and rectifier diode. Thus, the BD3508EKN is designed to enable
significant package profile downsizing and cost reduction. An external resistor allows the entire range of output voltage
configurations between 0.65 and 2.7V, while the NRCS (soft start) function enables a controlled output voltage ramp-up,
which can be programmed to whatever power supply sequence is required.
● Features
1) Internal high-precision reference voltage circuit(0.65V±1%)
2) Built-in VCC under voltage lock out circuit (VCC=3.80V)
3) NRCS (soft start) function reduces the magnitude of in-rush current
4) Internal Nch MOSFET driver offers low ON resistance (65mΩ typ)
5) Built-in current limit circuit(3.0A min)
6) Built-in thermal shutdown (TSD) circuit
7) Variable output (0.65~2.7V)
8) Incorporates high-power HQFN20V package: 4.2×4.2×0.9(mm)
● Applications
Notebook computers, Desktop computers, LCD-TV, DVD, Digital appliances
● Model Lineup
Oct. 2008
●Absolute Maximum Ratings
◎BD3508EKN
○Absolute Maximum Ratings(Ta=100℃)
PARAMETER
Input Voltage 1
Input Voltage 2
SYMBOL
VCC
VIN
RATING
6.0 *1
6.0 *1
UNIT
V
V
Enable Input Voltage
Power Dissipation 1
Power Dissipation 2
Power Dissipation 3
Power Dissipation 4
Ven 6.0 V
Pd1
0.5 *2
W
Pd2
0.75 *3
W
Pd3
1.75 *4
W
Pd4
2.0 *5
W
Operating Temperature Range
Topr
-10~+100
℃
Storage Temperature Range
Tstg
-55~+125
℃
Maximum Junction Temperature
Tjmax
+150
℃
*1 Should not exceed Pd.
*2 Reduced by 4mW/℃ for each increase in Ta≧25℃(no heat sink)
*3 Reduced by 6mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board,
with no copper foil on the bottom surface)
*4 Reduced by 14mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board,
with 60mm X 60 mm copper foil on the bottom surface…1-layer)
*5 Reduced by 16mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board,
with 60mm X 60 mm copper foil on the bottom surface…2-layer)
●Operating Conditions
○Operating Voltage(Ta=25℃)
PARAMETER
SYMBOL
Input Voltage 1
VCC
Input Voltage 2
VIN
Output Voltage Setting Range
Vo
Enable Input Voltage
Ven
NRCS Capacity
CNRCS
*6 VCC and VIN do not have to be implemented in the order listed.
★This product is not designed for use in radioactive environments.
MIN.
4.3
0.75
VFB
-0.3
0.001
MAX.
5.5
VCC-1 *6
2.7
5.5
1
UNIT
V
V
V
V
uF
|