Datasheet

TPS40400
www.ti.com SLUS930B –APRIL 2011– REVISED OCTOBER 2011
Command VOUT_SCALE_LOOP
Format Linear, two's complement binary
Bit Position 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
Access r r r r r r r/w r/w r/w r/w r/w r/w r/w r/w r/w r/w
Function Exponent Mantissa
Default Value 1 0 1 1 1 0 0 1 0 0 0 0 0 0 0 0
Exponent
Value fixed at –9 (dec).
Mantissa
Default value is 256 (dec). When combined with the exponent, the overall value of VOUT_SCALE_LOOP is 0.5
(dec). The maximum value for the mantissa is 512 for a VOUT_SCALE_LOOP value of 1.
FREQUENCY_SWITCH (33h)
The FREQUENCY_SWITCH command sets the switching frequency. Smarty Jones only supports frequencies
from 200 kHz to 2 MHz. Values written within the supported frequency range is rounded up to the nearest
supported increment. The contents of this register can be stored to non-volatile memory using the
STORE_DEFAULT_ALL or STORE_DEFAULT_CODE commands.
There are 14 distinct supported frequencies:
• 200 kHz
• 300 kHz
• 400 kHz
• 500 kHz
• 600 kHz (default)
• 700 kHz
• 800 kHz
• 900 kHz
• 1.0 MHz
• 1.2 MHz
• 1.4 MHz
• 1.6 MHz
• 1.8 MHz
• 1.9 MHz
The data word that accompanies this command is divided into a fixed 5-bit exponent and an 11-bit mantissa. The
5 most significant bits of the mantissa are fixed, while the lower six bits may be altered.
Command FREQUENCY_SWITCH
Format Linear, two's complement binary
Bit Position 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
Access r r r r r r r r r r r/w r/w r/w r/w r/w r/w
Function Exponent Mantissa
Default Value 0 0 1 0 1 0 0 0 0 0 0 1 0 0 1 1
Exponent
Fixed at 5(dec)
Mantissa
The upper five bits are fixed at 0.
The lower six bits are writeable with a default value of 19 (dec).
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