lm27241 National Semiconductor Corporation, lm27241 Datasheet - Page 23

• Manufacturer Part Number: lm27241
• Description: Synchronous Buck Regulator Controller For Mobile Systems
• Manufacturer: National Semiconductor Corporation

Bill of Materials
C4, C6, C8, C17
Designator
C10 - C13
C15, C16
C5, C8
SW1
SW2
R10
R11
R12
R13
R14
C14
C19
C20
C21
U1
R1
R2
R3
R4
R5
R6
R7
R8
R9
C1
C2
C3
D2
Q1
Q2
Q3
L1
Ceramic/Tantalum Input Capacitors
Small Signal FET VDYNAMIC
Snubber Capacitor (Optional)
Synchronous Buck Controller
V-enable & FPWM/SKIP Set
Dynamic Feedback Resistor
Snubber Resistor (Optional)
Tantalum Output Capacitor
Ceramic Output Capacitor
Q3 Gate to GND resistor
Compensation Capacitor
Compensation Capacitor
Compensation Capacitor
Ceramic Input Capacitor
PGOOD pull up resistor
Compensation Resistor
Compensation Resistor
Synchronous MOSFET
Enable pull up resistor
FPWM pull up resistor
VDD Filter Capacitor
Soft Start Capacitor
VBOOST Capacitor
Feedback Resistor
Feedback Resistor
Resistor (Optional)
Freq Set Resistor
VDD filter resistor
VBOOST Diode
Output Inductor
Top MOSFET
Vdynamic Set
Ilimit Resistor
Function
23
40.2 kΩ 1% 0805 (Optional)
10 kΩ 1% 0805 (Optional)
100 µF 4V B45192
4.99 kΩ 1% 0805
5.62 kΩ 1% 0805
1.00 kΩ 1% 0805
3.32 kΩ 1% 0805
12.7 kΩ 1% 0805
12.7 kΩ 1% 0805
22.1 kΩ 1% 0805
12.7 kΩ 1% 0805
1.33 kΩ 1% 0805
47 µF 2220 6.3V
PWM Controller
BSS138 SOT23
BAT54 SOT23
4700 pF 0805
2200 pF 0805
10Ω 1% 0805
10Ω 5% 0805
0.22 µF 0805
220 pF 0805
Description
0.1 µF 0805
0.1 µF 0805
IRF7821
IRF7832
HC1216
470 pF
10 µF
0Ω
Falco Electronics
TDK/EPCOS
International
International
Diodes INC
ON Semi
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
VISHAY
Rectifier
Rectifier
Vendor
EPCOS
NSC
TDK
TDK
TDK
TDK
TDK
TDK
TDK
TDK
TDK
www.national.com