SC4201
POWER MANAGEMENT
Pin Configuration
Ordering Information
Top View
Part Number (1)
P ackag e
SC4201IMSTR
MSOP-8
S C 4201E V B
Evaluation Board
Note:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
(MSOP-8)
Pin Descriptions
Pin
Pin Name
1
RT
Pin Function
Oscillator frequency is configured by connecting resistor R from RT to ground. Values for R can
be selected to provide desired 3 phase or 4 phase output frequencies.
FOUT ≈ {[1.25 /(15pF x Rt )]/ phase}
2
VD D
The power input connection for the device.
3
SYNC
SYNC is a positive edge triggered input with a threshold of 1.5V. SYNC should be grounded
when not required or connected to an external synchronization clock with frequency higher than
the on board oscillator frequency (with respect to internal clock).
4
A
Logic level output clock. Phase "A".
5
B
Logic level output clock. Phase "B".
6
C
Logic level output clock. Phase "C".
7
D
Logic level output clock and phase selection pin. Default operation 4 phase/2 phase
(90°/180°). Tie D to VDD to select 3 phase operation through A, B and C 120° out of phase.
8
GND
Reference ground and power ground for all functions.
Block Diagram
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SC4201
POWER MANAGEMENT
Application Information
Diagram in Figure 1 shows multi-phase operation of several power converters with fixed switching frequency
FSW.
VDD
Ph A
sync
+3 to 6V
= Fsw
SYNC
Ph B
sync
C
Ph C
sync
C
Ph D
Vout 3
L
PWM
= Fsw
GND
Vout 2
L
PWM
= Fsw
RT
Vout1
L
PWM
C
PWM
Vout 4
L
sync
= Fsw
C
optional 3 or 2/4 Phases
SC4201
Figure 1
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SC4201
POWER MANAGEMENT
Application Information (Cont.)
Diagram in Figure 2 demonstrates a multi-phase operation of a single power supply with current sharing
through the individual phases and with fixed switching frequency FSW.
VDD
Ph A
PWM
sync
+3 to 6V
L
= Fsw
SYNC
Ph B
PWM
sync
L
= Fsw
Vout
C
RT
Ph C
PWM
sync
L
= Fsw
GND
Ph D
PWM
L
sync
= Fsw
optional 3 or 2/4 Phases
SC4201
Figure 2
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SC4201
POWER MANAGEMENT
Application Information (Cont.)
Diagram in Figure 3 assumes variable switching frequency FSW, e.g. resonant power converters. This circuit
will require additional “FSW Control” block, which is a task for a power designer.
VDD
Ph A
sync
+3 to 6V
PWM
L
~ Fsw
SYNC
Ph B
sync
PWM
L
~ Fsw
Vout
C
Fsw control
RT
Ph C
sync
PWM
L
~ Fsw
GND
Ph D
sync
PWM
L
~ Fsw
optional 3 or 2/4 Phases
SC4201
Figure 3
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SC4201
POWER MANAGEMENT
Application Information (Cont.)
Diagram in Figure 4 demonstrates a synchronous operation of two (or more) SC4201 controllers. If the “time
delay” circuit is to be employed then 6-phase, 8-phase and other configurations become possible.
Power Section of choice
+3 to 6V
VDD
Ph A
sync
PWM
L
V DD
Ph A
+3 to 6V
~ Fsw
Time Delay
(optional)
SYNC
Ph B
sync
PWM
L
SYNC
Ph B
RT
Ph C
GND
Ph D
~ Fsw
Vout
C
Fsw control
RT
Ph C
sync
PWM
L
~ Fsw
GND
Ph D
sync
PWM
L
~ Fsw
SC4201 - A
optional 3 or 2/4 Phases
SC4201 - B
Figure 4
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SC4201
POWER MANAGEMENT
Evaluation Board Schematic
3 Phase - 4 Phase
+3 to 6V
R3
1k
U1
SC4201
1
RT
GND
8
2
VDD
D
7
D Out
3
SYNC
C
6
C Out
4
A
B
5
B Out
Run - Sync
Sync
J1
R1
15k
C1
1.0
C2
0.1
A Out
R2
100K
C3
22pF
C4
22pF
C5
22pF
C6
22pF
Top View
Layout
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SC4201
POWER MANAGEMENT
Outline Drawing - MSOP-8
Land Pattern - MSOP-8
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
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