SQ48 Power-One, SQ48 Datasheet - Page 4

• Manufacturer Part Number: SQ48
• Description: Sq48 Dc-dc Series
• Manufacturer: Power-One

designer must, if necessary, decrease the maximum
current (originally obtained from the derating curves)
by the same percentage to ensure the converter’s
actual output power remains at or below the
maximum allowable output power.
Output Voltage Adjust /TRIM (Pin 6)
The output voltage can be adjusted up 10% or down
20% for Vout ≥ 1.5 V, and ±10% for Vout = 1.2 V
relative to the rated output voltage by the addition of
an externally connected resistor. For output voltage
3.3 V, trim up to 10% is guaranteed only at
Vin ≥ 40 V, and it is marginal (8% to 10%) at
Vin = 36 V.
The TRIM pin should be left open if trimming is not
being used. To minimize noise pickup, a 0.1 µF
capacitor is connected internally between the TRIM
and SENSE(-) pins.
To increase the output voltage, refer to Fig. C. A trim
resistor, R
TRIM (Pin 6) and SENSE(+) (Pin 7), with a value of:
for 1.5 – 12 V.
where,
SEP 14, 2005 revised to NOV 06, 2006
R
R
R
R
Vin
V
Δ
V
T
T
T
T
O
O
−
−
−
=
−INCR
INCR
INCR
INCR
−NOM
−REQ
Fig. C: Configuration for increasing output voltage.
(V
=
=
=
O
=
=
=
120
84.6
5.11(100
-
Δ
REQ
Δ
Required value of trim-up resistor [kΩ]
Nominal value of output voltage [V]
Desired (trimmed) output voltage [V].
V
T-INCR
O
−
−
−
-
ON/OFF
Vin (+)
NOM
Vin (-)
9
V
7.2
, should be connected between the
O
-
+
NOM
1.225Δ
Δ)V
Semi
)
(Top View)
Converter
O
X
Q
−
NOM
TM
100
Family
−
[%]
626
[kΩ] (1.2 V)
[kΩ] (1.0 V)
SENSE (+)
SENSE (-)
Vout (+)
Vout (-)
TRIM
−
10.22
R
T-INCR
[kΩ],
Rload
Page 4 of 64
[V
36-75 VDC Input; 1.0-12 VDC Output
When trimming up, care must be taken not to exceed
the converter‘s maximum allowable output power. See
the previous section for a complete discussion of this
requirement.
To decrease the output voltage (Fig. D), a trim
resistor, R
TRIM (Pin 6) and SENSE(-) (Pin 5), with a value of:
where,
and Δ is defined above.
Note:
The above equations for calculation of trim resistor values match
those typically used in conventional industry-standard quarter-
bricks and one-eighth bricks (except for 1.2 V and 1.0 V outputs).
Converters with output voltages 1.2 V and 1.0 V are
available with alternative trim feature to provide the
customers with the flexibility of second sourcing.
These converters have a “T” character in the part
number. The trim equations of “T” version of
converters and more information can be found in
Application Note 103.
Trimming/sensing beyond 110% of the rated output
voltage is not an acceptable design practice, as this
condition could cause unwanted triggering of the
output overvoltage protection (OVP) circuit. The
designer should ensure that the difference between
the voltages across the converter’s output pins and its
sense pins does not exceed 10% of V
This equation is applicable for any condition of output
sensing and/or output trim.
R
R
R
R
Vin
OUT
T
T
T
T
−
−
−
−DECR
DECR
DECR
DECR
) (
+
Fig. D: Configuration for decreasing output voltage.
−
SQ48 DC-DC Series Data Sheet
=
=
=
V
=
|
700
700
511
OUT
Δ
Δ
Δ
Required value of trim-down resistor [kΩ]
T-DECR
|
(
−
−
−
−
)]
ON/OFF
Vin (+)
Vin (-)
15
10.22
17
−
, should be connected between the
[V
SENSE
Semi
(Top View)
Converter
) (
+
Q
−
TM
Family
V
SENSE
[kΩ] (1.5 – 12 V)
[kΩ] (1.2 V)
[kΩ] (1.0 V)
(
SENSE (+)
SENSE (-)
−
)]
www.power-one.com
Vout (+)
Vout (-)
TRIM
≤
OUT
V
O
(
-
NOM
NOM
R
), or:
X
T-DECR
10%
Rload
[V]