LTM8047 LINER [Linear Technology], LTM8047 Datasheet - Page 12

• Manufacturer Part Number: LTM8047
• Description: 3.1VIN to 32VIN Isolated ?Module DC/DC Converter
• Manufacturer: LINER [Linear Technology]

BIAS Pin Considerations
The BIAS pin is the output of an internal linear regulator
that powers the LTM8048’s internal circuitry. It is set to
3V and must be decoupled with a low ESR capacitor of at
least 4.7μF . The LTM8048 will run properly without apply-
ing a voltage to this pin, but will operate more efficiently
and dissipate less power if a voltage greater than 3.1V is
applied. At low V
more output current if BIAS is 3.1V or greater. Up to 32V
may be applied to this pin, but a high BIAS voltage will
cause excessive power dissipation in the internal circuitry.
For applications with an input voltage less than 15V, the
BIAS pin is typically connected directly to the V
input voltages greater than 15V, it is preferred to leave the
BIAS pin separate from the V
a separate voltage source or left running from the internal
LTM8048
APPLICATIONS INFORMATION
LTM8048 Table 1b. Recommended Component Values and Configuration for Specific V
Note: Do not allow BIAS to exceed V
12
3.1V to 32V
3.1V to 32V
3.1V to 32V
3.1V to 32V
3.1V to 32V
3.1V to 29V
3.1V to 26V
3.1V to 21V
18V to 32V
18V to 32V
18V to 32V
18V to 32V
18V to 32V
18V to 29V
18V to 26V
9V to 15V
9V to 15V
9V to 15V
9V to 15V
9V to 15V
9V to 15V
9V to 15V
9V to 15V
V
IN
V
1.71V
2.02V
2.34V
3.08V
3.92V
8.85V
1.71V
2.02V
2.34V
3.08V
3.92V
8.85V
1.71V
2.02V
2.34V
3.08V
3.92V
8.85V
5.7V
5.7V
5.7V
13V
13V
OUT1
IN
, the LTM8048 will be able to deliver
V
1.2V
1.5V
1.8V
2.5V
3.3V
1.2V
1.5V
1.8V
2.5V
3.3V
1.2V
1.5V
1.8V
2.5V
3.3V
12V
12V
OUT2
5V
8V
5V
8V
5V
8V
IN
, a bulk input capacitor is required.
IN
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
3.1V to 15V or Open
pin, either powered from
V
V
V
V
V
V
V
V
V
BIAS
IN
IN
IN
IN
IN
IN
IN
IN
IN
pin. For
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 25V, 0805
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 25V, 0805
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
2.2μF , 50V, 1206
C
IN
regulator. This has the added advantage of keeping the
physical size of the BIAS capacitor small. Do not allow
BIAS to rise above V
Soft-Start
For many applications, it is necessary to minimize the
inrush current at start-up. The built-in soft-start circuit
significantly reduces the start-up current spike and output
voltage overshoot by applying a capacitor from SS to GND.
When the LTM8048 is enabled, whether from V
a sufficiently high voltage or RUN being pulled high, the
LTM8048 will source approximately 10μA out of the SS
pin. As this current gradually charges the capacitor from
SS to GND, the LTM8048 will correspondingly increase
the power delivered to the output, allowing for a graceful
turn-on ramp.
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
100μF , 6.3V, 1210
47μF , 6.3V, 1210
47μF , 6.3V, 1210
47μF , 6.3V, 1210
22μF , 16V, 1210
22μF , 10V, 1206
10μF , 16V, 1210
22μF , 16V, 1210
22μF , 10V, 1206
10μF , 16V, 1210
22μF , 16V, 1210
22μF , 10V, 1206
C
OUT1
OUT2
Voltages (T
IN
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 6.3V, 1206
10μF , 10V, 1206
10μF , 16V, 1206
10μF , 10V, 1206
10μF , 16V, 1206
10μF , 10V, 1206
.
C
OUT2
A
= 25°C)
R
16.5k
14.7k
13.3k
10.5k
8.66k
6.19k
4.12k
2.94k
16.5k
14.7k
13.3k
10.5k
8.66k
6.19k
4.12k
2.94k
16.5k
14.7k
13.3k
10.5k
8.66k
6.19k
4.12k
ADJ1
IN
reaching
2.32M
1.07M
2.32M
1.07M
2.32M
1.07M
R
88.7k
56.2k
88.7k
56.2k
88.7k
Open
487k
294k
162k
Open
487k
294k
162k
Open
487k
294k
162k
ADJ2
8048fa