BD8314NUV-E2 Rohm Semiconductor, BD8314NUV-E2 Datasheet - Page 10

• Manufacturer Part Number: BD8314NUV-E2
• Description: IC SWITCHING REG W/MOSFET SON10
• Manufacturer: Rohm Semiconductor
• Series: -r
• Type: Step-Up (Boost), PWMr

Specifications of BD8314NUV-E2

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 4 V ~ 12 V
• Current - Output: 2.5A
• Frequency - Switching: 1.2MHz
• Voltage - Input: 3 V ~ 12 V
• Operating Temperature: -25°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-VFDFN Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

●Selection of Part for Applications
BD8314NUV
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(1) Inductor
(2) Output capacitor
(3) Output voltage setting
A shielded inductor that satisfies the current rating
(current value, Ipecac as shown in the drawing below)
and has a low DCR (direct resistance component) is
recommended.
Inductor values affect inductor ripple current, which will
cause output ripple.
Ripple current can be reduced as the coil L value
becomes larger and the
switching frequency becomes higher.
(η: Efficiency, ∆IL: Output ripple current, f: Switching frequency)
As a guide, inductor ripple current should be set at about 20 to 50% of the maximum input current.
* Current over the coil rating flowing in the coil brings the coil into magnetic saturation, which may lead to lower
A ceramic capacitor with low ESR is recommended for output in order to reduce output ripple.
There must be an adequate margin between the maximum rating and output voltage of the capacitor, taking the DC
bias property into consideration.
Output ripple voltage is obtained by the following equation.
Setting must be performed so that output ripple is within the allowable ripple voltage.
The internal reference voltage of the ERROR AMP is 1.0 V. Output voltage is obtained by Equation (4) of Fig. 33,
but it should be designed taking about 50 Ω, an error of NMOS ON resistance of SWOUT into consideration.
Δ
I
V
peak
PP
efficiency or output oscillation. Select an inductor with an adequate margin so that the peak current does not
exceed the rated current of the coil.
IL



Fig.34
I
V
I
OUT
OUT
L
IN



V
f

V
OUT

V
V
Setting of voltage feedback resistance
OUT
OUT
C
OUT
O


/

V
R2
R1
V
VOUT
V
IN
V
IN
OUT
IN


/
SWOUT
η
1
f

[
] A
INV
I
Δ
OUT
IL

/
1.0V
VREF
[ 2
ERROR AMP
R
ESR
] A
[
] V
・・・(1)
・・・(2)
STB
10/15
V
・・・(3)
O


R
1
R

2
R
2


. 1
[ 0
] V
Fig.33 Inductor current
・・・(4)
Δ I
L
Technical Note
2010.11 - Rev.C