LTM8057_15 Datasheet, PDF (13/20 Pages) Linear Technology – 3.1VIN to 31VIN Isolated Module DC/DC Converter

LTM8057
APPLICATIONS INFORMATION
Table 2. Safety Rated Capacitors
MANUFACTURER PART NUMBER
DESCRIPTION
Murata
Electronics
GA343DR7GD472KW01L
4700pF, 250V AC, X7R,
4.5mm × 3.2mm
Capacitor
Johanson
Dielectrics
302R29W471KV3E-****-SC 470pF, 250V AC, X7R,
4.5mm × 2mm
Capacitor
Syfer Technology 1808JA250102JCTSP
100pF, 250V AC, C0G,
1808 Capacitor
PCB Layout
Most of the headaches associated with PCB layout have
been alleviated or even eliminated by the high level of
integration of the LTM8057. The LTM8057 is neverthe-
less a switching power supply, and care must be taken to
minimize electrical noise to ensure proper operation. Even
with the high level of integration, you may fail to achieve
specified operation with a haphazard or poor layout. See
Figure 3 for a suggested layout. Ensure that the grounding
and heat sinking are acceptable.
A few rules to keep in mind are:
1. Place the R_ADJ resistor as close as possible to their
respective pins.
2. Place the C_IN capacitor as close as possible to the V_IN
and GND connections of the LTM8057.
3. Place the C_OUT1 capacitor as close as possible to V_OUT
and V_OUT–.
4. Place the C_IN and C_OUT capacitors such that their
ground current flow directly adjacent or underneath
the LTM8057.
5. Connect all of the GND connections to as large a copper
pour or plane area as possible on the top layer. Avoid
breaking the ground connection between the external
components and the LTM8057.
V_OUT
C_OUT1
V_OUT–
LTM8058
ADJ
SS
BIAS
C_BIAS
RUN
C_IN
THERMAL/INTERCONNECT VIAS
V_IN
8057 F03
Figure 3. Layout Showing Suggested External Components, Planes and Thermal Vias
For more information www.linear.com/LTM8057
8057f
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