ltm8031 Linear Technology Corporation, ltm8031 Datasheet - Page 6

• Manufacturer Part Number: ltm8031
• Description: Ultralow Noise Emc 36v, 1a Dc/dc ?module Regulator
• Manufacturer: Linear Technology Corporation

LTM8031
TYPICAL PERFORMANCE CHARACTERISTICS
PIN FUNCTIONS
V
internal regulator and to the internal power switch. This
pin must be locally bypassed with an external, low ESR
capacitor of at least 1μF .
FIN (K3, L3): Filtered Input. This is the node after the input
EMI fi lter. Use this only if there is a need to modify the
behavior of the integrated EMI fi lter or if V
rapidly; otherwise, leave these pins unconnected. See the
Applications Information section for more details.
GND (Bank 2): Tie these GND pins to a local ground plane
below the LTM8031 and the circuit components. Return
the feedback divider (R
V
capacitor and the output load between these pins and
GND pins.
AUX (Pin H5): Low Current Voltage Source for BIAS. In
many designs, the BIAS pin is simply connected to V
The AUX pin is internally connected to V
adjacent to the BIAS pin to ease printed circuit board rout-
ing. Although this pin is internally connected to V
not connect this pin to the load. If this pin is not tied to
BIAS, leave it fl oating.
6
IN
OUT
(Bank 3): The V
(Bank 1): Power Output Pins. Apply the output fi lter
–10
90
80
70
60
50
40
30
20
10
0
IN
0
Radiated Emissions
V
V
pin supplies current to the LTM8031’s
100
IN
OUT
= 36V
ADJ
= 10V AT 1A
200
) to this net.
300
FREQUENCY (MHz)
400
500
600 700
OUT
800
IN
and is placed
900
rises or falls
8031 G19
1000
OUT
EN55022
CLASS B
LIMIT
OUT
, do
.
BIAS (Pin H4): The BIAS pin connects to the internal power
bus. Connect to a power source greater than 2.8V. If the
output is greater than 2.8V, connect this pin to AUX. If the
output voltage is less, connect this to a voltage source
between 2.8V and 25V. Also, make sure that BIAS + V
is less than 56V.
RUN/SS (Pin L5): Pull RUN/SS pin to less than 0.2V to
shut down the LTM8031. Tie to 2.5V or more for normal
operation. If the shutdown feature is not used, tie this pin
to the V
see the Applications Information section.
RT (Pin G7): The RT pin is used to program the switching
frequency of the LTM8031 by connecting a resistor from
this pin to ground. The Applications Information section of
the data sheet includes a table to determine the resistance
value based on the desired switching frequency. Minimize
capacitance at this pin.
SHARE (Pin H7): Tie this to the SHARE pin of another
LTM8031 when paralleling the outputs.
–10
90
80
70
60
50
40
30
20
10
0
IN
0
Radiated Emissions
V
V
pin. RUN/SS also provides a soft-start function;
100
IN
OUT
T
A
= 36V
= 2.5V AT 1A
200
= 25°C, unless otherwise noted.
300
FREQUENCY (MHz)
400
500
600 700
800
900
8031 G20
1000
EN55022
CLASS B
LIMIT
8031fa
IN