Rainbow Electronics MAX17480 - Manual (Page 31)

MAX17480
AMD 2-/3-Output Mobile Serial
VID Controller
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When using a current-sense resistor for accurate output-
voltage positioning, the circuit requires a differential RC
filter to eliminate the AC voltage step caused by the
equivalent series inductance (L
ESL ) of the current-sense
resistor (see Figure 7). The ESL-induced voltage step
does not affect the average current-sense voltage, but
results in a significant peak current-sense voltage error
that results in unwanted offsets in the regulation voltage
and early current-limit detection. Similar to the inductor
DCR sensing method above, the RC filter’s time con-
stant should match the L/R time constant formed by the
current-sense resistor’s parasitic inductance:
SVID[6:0]
OUTPUT
VOLTAGE
(V)
SVID[6:0]
OUTPUT
VOLTAGE
(V)
SVID[6:0]
OUTPUT
VOLTAGE
(V)
SVID[6:0]
OUTPUT
VOLTAGE
(V)
000_0000 1.5500 010_0000 1.1500 100_0000 0.7500 110_0000 0.3500
000_0001 1.5375 010_0001 1.1375 100_0001 0.7375 110_0001 0.3375
000_0010 1.5250 010_0010 1.1250 100_0010 0.7250 110_0010 0.3250
000_0011 1.5125 010_0011 1.1125 100_0011 0.7125 110_0011 0.3125
000_0100 1.5000 010_0100 1.1000 100_0100 0.7000 110_0100 0.3000
000_0101 1.4875 010_0101 1.0875 100_0101 0.6875 110_0101 0.2875
000_0110 1.4750 010_0110 1.0750 100_0110 0.6750 110_0110 0.2750
000_0111 1.4625 010_0111 1.0625 100_0111 0.6625 110_0111 0.2625
000_1000 1.4500 010_1000 1.0500 100_1000 0.6500 110_1000 0.2500
000_1001 1.4375 010_1001 1.0375 100_1001 0.6375 110_1001 0.2375
000_1010 1.4250 010_1010 1.0250 100_1010 0.6250 110_1010 0.2250
000_1011 1.4125 010_1011 1.0125 100_1011 0.6125 110_1011 0.2125
000_1100 1.4000 010_1100 1.0000 100_1100 0.6000 110_1100 0.2000
000_1101 1.3875 010_1101 0.9875 100_1101 0.5875 110_1101 0.1875
000_1110 1.3750 010_1110 0.9750 100_1110 0.5750 110_1110 0.1750
000_1111 1.3625 010_1111 0.9625 100_1111 0.5625 110_1111 0.1625
001_0000 1.3500 011_0000 0.9500 101_0000 0.5500 111_0000 0.1500
001_0001 1.3375 011_0001 0.9375 101_0001 0.5375 111_0001 0.1375
001_0010 1.3250 011_0010 0.9250 101_0010 0.5250 111_0010 0.1250
001_0011 1.3125 011_0011 0.9125 101_0011 0.5125 111_0011 0.1125
001_0100 1.3000 011_0100 0.9000 101_0100 0.5000 111_0100 0.1000
001_0101 1.2875 011_0101 0.8875 101_0101 0.4875 111_0101 0.0875
001_0110 1.2750 011_0110 0.8750 101_0110 0.4750 111_0110 0.0750
001_0111 1.2625 011_0111 0.8625 101_0111 0.4625 111_0111 0.0625
001_1000 1.2500 011_1000 0.8500 101_1000 0.4500 111_1000 0.0500
001_1001 1.2375 011_1001 0.8375 101_1001 0.4375 111_1001 0.0375
001_1010 1.2250 011_1010 0.8250 101_1010 0.4250 111_1010 0.0250
001_1011 1.2125 011_1011 0.8125 101_1011 0.4125 111_1011 0.0125
001_1100 1.2000 011_1100 0.8000 101_1100 0.4000 111_1100 OFF
001_1101 1.1875 011_1101 0.7875 101_1101 0.3875 111_1101 OFF
001_1110 1.1750 011_1110 0.7750 101_1110 0.3750 111_1110 OFF
001_1111 1.1625 011_1111 0.7625 101_1111 0.3625 111_1111 OFF
Table 4. Output-Voltage VID DAC Codes
Note: The NB SMPS output voltage has an offset of +12.5mV.