Datasheet

(20kΩ typical) connected between +Vout and –Vout with the wiper to the Trim
pin.
Output overvoltage protection is monitored at the output voltage pin, not
the Sense pin. Therefore, excessive voltage differences between VOUT and
Sense in conjunction with trim adjustment of the output voltage can cause the
overvoltage protection circuitry to activate (see Performance Specifications for
overvoltage limits). Power derating is based on maximum output current and
voltage at the converter's output pins. Use of trim and sense functions can
cause output voltages to increase, thereby increasing output power beyond the
conveter's specified rating, or cause output voltages to climb into the output
overvoltage region. Therefore, the designer must ensure:
(VOUT at pins) × (IOUT) ≤ rated output power
LOAD
+OUTPUT
–INPUT
Sense Current
Contact and PCB resistance
losses due to IR drops
Contact and PCB resistance
losses due to IR drops
Sense Return
+INPUT
ON/OFF
CONTROL
TRIM
+SENSE
–OUTPUT
–SENSE
4
5
1
3
6
8
I
OUT Return
I
OUT
7
2
Remote Sense
Note: The Sense and VOUT lines are internally connected through low-value
resistors. Nevertheless, if the sense function is not used for remote regulation
the user must connect the +Sense to +VOUT and -Sense to –VOUT at the DC-DC
converter pins.
UVQ series converters employ a sense feature to provide point of use regu-
lation, thereby overcoming moderate IR drops in pcb conductors or cabling.
The remote sense lines carry very little current and therefore require minimal
cross-sectional-area conductors. The sense lines, which are capacitively
coupled to their respective output lines, are used by the feedback control-loop
to regulate the output. As such, they are not low impedance points and must
be treated with care in layouts and cabling. Sense lines on a pcb should be run
adjacent to dc signals, preferably ground. In cables and discrete wiring applica-
tions, twisted pair or other techniques should be implemented.
UVQ series converters will compensate for drops between the output voltage
at the DC-DC and the sense voltage at the DC-DC provided that:
[VOUT(+) –VOUT(–)] – [Sense(+) –Sense (–)] ≤ 10% VOUT
Figure 8. Remote Sense Circuit Configuration
FEATURES AND OPTIONS
UP
VO – 3.3
R
T (kΩ) =
–10.2
13.3(VO – 1.226)
3.3 – V
O
RT (kΩ) =
–10.2
16.31
DOWN
UP
VO – 5
R
T (kΩ) =
–10.2
20.4(VO – 1.226)
5 – VO
RT (kΩ) =
–10.2
25.01
DOWN
UP
VO – 12
R
T (kΩ) =
–10.2
49.6(VO – 1.226)
12 – V
O
RT (kΩ) =
–10.2
60.45
DOWN
UP
VO – 15
R
T (kΩ) =
–10.2
62.9(VO – 1.226)
15 – V
O
RT (kΩ) =
–10.2
76.56
DOWN
UP
VO – 18
R
T (kΩ) =
–10.2
75.5(VO – 1.226)
18 – V
O
RT (kΩ) =
–10.2
92.9
DOWN
UVQ-3.3/35-D48
UVQ-5/25-D24, UVQ-5/20-D48
UVQ-12/8-D24, -12/10-D48
UVQ-15/7-D24, -D48
UVQ-18/5.6-D24, -18/6-D48
UP
VO – 2.5
R
T (kΩ) =
–10.2
10(VO – 1.226)
2.5 – V
O
RT (kΩ) =
–10.2
12.26
DOWN
UVQ-2.5/40-D48, UVQ-2.5/35-D24
UVQ-1.5/40-D24
UP
VO – 1.5
R
T (kΩ) =
–10.2
6.23(VO – 1.226)
1.5 – V
O
RT (kΩ) =
–10.2
7.64
DOWN
101(VO – 1.226)
UP
VO – 24
R
T (kΩ) =
–10.2
24 – VO
RT (kΩ) =
–10.2
124.2
DOWN
UVQ-24/4.5-D24, -D48
210.75(VO – 1.226)
UP
VO – 48
R
T (kΩ) =
–10.2
48 – VO
RT (kΩ) =
–10.2
250
DOWN
UVQ-48/2.5-D24, -D48
Trim Up Trim Down
Trim Equations
MDC_UVQ Models.F04 Page 22 of 25
UVQ Series
Low Profile, Isolated Quarter Brick
2.5–40 Amp DC-DC Converters
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