BD9007F-E2 Rohm Semiconductor, BD9007F-E2 Datasheet - Page 10

• Manufacturer Part Number: BD9007F-E2
• Description: IC REG SW 2A FLEX STEPDOWN 8-SOP
• Manufacturer: Rohm Semiconductor
• Type: Step-Down (Buck)r

Specifications of BD9007F-E2

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1 ~ 35 V
• Current - Output: 2A
• Frequency - Switching: 50kHz ~ 500kHz
• Voltage - Input: 7 ~ 35 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOP
• Power - Output: 690mW
• Output Voltage: 2. 6 V
• Output Current: 2 A
• Input Voltage: 7 V to 35 V
• Operating Temperature Range: - 40 C to + 105 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 100 %
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: BD9007F-E2TR

●Description of external components
BD9006F, BD9006HFP, BD9007F, BD9007HFP
© 2009 ROHM Co., Ltd. All rights reserved.
Vo=Output voltage, V
Io (Max.)=Maximum load current, f=Oscillation frequency
1. Setting or output voltage
2. Selection of coil (L1)
3. Selection of output capacitor (Co)
www.rohm.com
The value of the coil can be obtained by the formula shown
If this coil is not set to the optimum value, normal (continuous)
Oscillation may not be achieved. Furthermore, set the value of
the coil with an adequate margin so that the peak current
passing through the coil will not exceed the rated current of the
coil.
Output voltage can be obtained by the formula shown below:
Use the formula to select the R1 and R2.
Furthermore, set the R2 to 30kΩ or less.
Select the current passing through the R1 and R2 to be small
enough for the output current.
below:
Set the rating of the capacitor with an adequate margin to the
output voltage. Also, set the maximum allowable ripple current
with an adequate margin to ∆IL.
time should be shorter than the soft start time. Select the
output capacitor having a value smaller than that obtained by
the formula shown below.
I
If this capacitances is not optimum, faulty startup may result.
The output capacitor can be determined according to the
output ripple voltage ∆Vo(p-p) required. Obtain the required
ESR value by
capacitance.
LIMIT
(※3.0m is soft start
L1=(V
∆Io: Output ripple current
∆Io should typically be approximately 20 to 30% of Io.
C
：2A (BD9006F,BD9006HFP, BD9007F,BD9007HFP)
MAX
∆IL=(V
∆Vpp=∆IL×ESR+(∆IL×Vo)/(2×Co×f×V
IN
-Vo)×Vo / (V
=
Vo=0.8×(1+R1/R2)
IN
-Vo)×Vo/(L×f×V
the formula shown below
3.0m×(I
IN
time(min).)
IN
(Max.)=Maximum input voltage
Design Procedure
×f×∆Io)
LIMIT
Vo
-Io(Max))
IN
V
IN
)
Furthermore,
＋
C28
R
T
and then select the
IN
C
IN
)
the output rise
V
RT
EN/SYNC
IN
Fig.23
10/17
GND
When Vo=3.3V, V
Io(Max.)=1A and f=300kHz
When V
When V
V
∆IL=(13.2-3.3)×3.3/(33×10
When I
C
IN
MAX
INV
SW
FB
=13.2V, Vo=3.3V, L=33µH, f=300kHz
3.3=0.8×(1+R1/15kΩ)
R1=46.875kΩ≒47kΩ
=0.25
L1=(13.2-3.3)×3.3/{13.2×300k×(1×0.3)}
≒910µ
=3.0m×(2-1)/3.3
=27.5µH≒33µH
LIMIT
O
IN
=3.3V and R2=15kΩ
R3
=13.2V,
: 2A, Io(Max)=1A, Vo=3.3V
D1
C1
L1
IN
Vo=3.3V, Io=1A and f=300kHz,
Sample Calculations
＋
Co
(Typ.)=13.2V
Vo
R1
R2
-6
×300×10
3
Technical Note
×13.2)
2009.05 - Rev.A
R1=47kΩ
L1=33µH
∆IL=0.25A
C
MAX
=910µF