Datasheet

2 MHz
Clock Frequency
Time
Spread Spectrum
frequency
10 kHz triangle
wave
Peak frequency deviation
2 kHz triangle
wave
LP3906
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SNVS456M AUGUST 2006REVISED MAY 2013
BUCK 2 RAMP CONTROL REGISTER (B2RC) - 0x2B
This register allows the user to program the rate of change between the target voltages of Buck 2
D7 D6-4 D3-0
Name - - - - - - - - B2RS
Access - - - - - - - - R/W
Data Reserved Reserved Data Code Ramp Rate mV/us
4h'0 Instant
4h'1 1
4h'2 2
4h'3 3
4h'4 4
4h'5 5
4h'6 6
4h'7 7
4h'8 8
4h'9 9
4h'A 10
4h'B - 4h'F 10
Reset 0 010 1000
BUCK FUNCTION REGISTER (BFCR) 0x38
This register allows the Buck switcher clock frequency to be spread across a wider range, allowing for less
Electro-magnetic Interference (EMI). The spread spectrum modulation frequency refers to the rate at which the
frequency ramps up and down, centered at 2 MHz.
D7-2 D1 D0
Name BK_SLOMOD BK_SSEN
Access R/W R/W
Data Reserved Buck Spread Spectrum Modulation Spread Spectrum Function Output
0 – 10 kHz triangular wave 0 – Disabled
1 – 2 kHz triangular wave 1 Enabled
Reset 000010 1 0
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