AFL12005D Datasheet, PDF (8/11 Pages) International Rectifier – HYBRID-HIGH RELIABILITY DC/DC CONVERTER

AFL120XXD Series
Input Filter
The AFL120XXD series converters incorporate a single
stage LC input filter whose elements dominate the input
load impedance characteristic during the turn-on sequence.
The input circuit is as shown in Figure IV.
Figure IV. Input Filter Circuit
Pin 1
16.8uH
Pin 2
0.78uF
Table 1. Output Voltage Trim Values and Limits
AFL12005D
AFL12012D
AFL12015D
V_out
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.583
R_adj
0
12.5K
33.3K
75K
200K
∞
190K
65K
23K
2.5K
0
V_out
12.5
12.4
12.3
12.2
12.1
12.0
11.7
11.3
10.8
10.6
10.417
R_adj
0
47.5K
127K
285K
760K
∞
975K
288K
72.9K
29.9K
0
V_out
15.5
15.4
15.3
15.2
15.1
15.0
14.6
14.0
13.5
13.0
12.917
R_adj
0
62.5K
167K
375K
1.0M
∞
1.2M
325K
117K
12.5K
0
Undervoltage Lockout
A minimum voltage is required at the input of the converter
to initiate operation. This voltage is set to 74 ± 4.0V. To
preclude the possibility of noise or other variations at the
input falsely initiating and halting converter operation, a
hysteresis of approximately 7.0V is incorporated in this
circuit. Thus if the input voltage droops to 67 ± 4.0V, the
converter will shut down and remain inoperative until the
input voltage returns to ≈ 74V.
Output Voltage Adjust
By use of the trim pin (10), the magnitude of output voltages
can be adjusted over a limited range in either a positive or
negative direction. Connecting a resistor between the trim
pin and either the output return or the positive output will
raise or lower the magnitude of output voltages. The span
of output voltage adjustment is restricted to the limits shown
in Table I.
Note that the nominal magnitude of output voltage resides in
the middle of the table and the corresponding resistor value
is set to ∞. To set the magnitude greater than nominal, the
adjust resistor is connected to output return. To set the
magnitude less than nominal, the adjust resistor is connected
to the positive output. (Refer to Figure V.)
For output voltage settings that are within the limits, but
between those listed in Table I, it is suggested that the
resistor values be determined empirically by selection or by
use of a variable resistor. The value thus determined can
then be replaced with a good quality fixed resistor for
permanent installation.
When use of this adjust feature is elected, the user should
be aware that the temperature performance of the converter
output voltage will be affected by the temperature
performance of the resistor selected as the adjustment
element and therefore, is advised to employ resistors with a
tight temperature coefficient of resistance.
Figure V. Connection for V_OUT Adjustment
AFL120xxD
12
Enable 2
Share
+ Sense
R_ADJ
- Sense
Return
+ Vout
7
To
Loads
Connect R_adj to + to increase, - to decrease
8
www.irf.com