B048K030T21 Datasheet, PDF (12/15 Pages) Vicor Corporation – VI Chip - BCM Bus Converter Module

Application Note (continued)
PRELIMINARY
The thermal resistance of the PCB to the surrounding environment in
proximity to V•I Chips may be reduced by low profile heat sinks surface
mounted to the PCB.The PCB may also be coupled to a cold plate by low
thermal resistance standoff elements as a means of achieving effective
cooling for an array of V•I Chips, without a direct interface to their case.
CASE 3—Combined direct convection to the air and conduction to the PCB.
Parallel use of the V•I Chip internal thermal resistances (including Junction-
to-Case and Junction-to-BGA) in series with external thermal resistances
provides an efficient thermal management strategy as it reduces total
thermal resistance. This may be readily estimated as the parallel network of
two pairs of series configured resistors.
V•I Chip Bus Converter Module
V•I Chip Bus Converter Level 1 DC Behavioral Model for 48 V to 3 V, 210 W
IOUT
ROUT
+
1.8 mΩ
+
1/16 • Iout
V•I
1/16 • Vin
++
VIN
IQ
69 mA
––
K
–
VOUT
–
©
Figure 25—This model characterizes the DC operation of the V•I Chip bus converter, including the converter transfer function and its losses. The model enables
estimates or simulations of output voltage as a function of input voltage and output load, as well as total converter power dissipation or heat generation.
V•I Chip Bus Converter Level 2 Transient Behavioral Model for 48 V to 3 V, 210 W
L IN = 20 nH
+
CIN
VIN
RC_IN
1.3 mΩ
4µF
IQ
69 mA
–
1/16 • Iout
IOUT
0.12 nH
V•I
++
0.6 mΩ
1/16 • Vin
––
K
ROUT
Lout = 1.1 nH
1.8 mΩ
COUT
RC_OUT
0.085 mΩ
254 µF
+
VOUT
–
©
Figure 26—This model characterizes the AC operation of the V•I Chip bus converter including response to output load or input voltage transients or steady state
modulations. The model enables estimates or simulations of input and output voltages under transient conditions, including response to a stepped load with or
without external filtering elements.
vicorpower.com 800-735-6200
V•I Chip Bus Converter Module
B048K030T21
Rev. 1.0
Page 12 of 15