SQ24 Power-One, SQ24 Datasheet - Page 4

• Manufacturer Part Number: SQ24
• Description: Sq24 Series Dc-dc Converter Data Sheet 18-36 Vdc Input; Standard Outputs From 1-12 Vdc
• Manufacturer: Power-One

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 converter’s output voltage can be adjusted up 10% or
down 20% for Vout ≥ 1.5V, and ±10% for Vout = 1.2V and
1.0 V, relative to the rated output voltage by the addition of
an externally connected resistor. For output voltages 3.3V,
trim up to 10% is guaranteed only at Vin ≥ 20V, and it is
marginal (8% to 10%) at Vin = 18V depending on load
current.
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
(Pin 6) and SENSE(+) (Pin 7), with a value of:
where,
When trimming up, care must be taken not to exceed the
converter‘s maximum allowable output power. See previous
section for a complete discussion of this requirement.
AUG 25, 2006 revised to MAR 19, 2007
R
R
R
R
V
Δ
V
T
T
T
T
O
O
−
−
−
=
−INCR
Vin
INCR
INCR
INCR
−NOM
−REQ
(V
=
=
=
O
=
=
=
-
485
323
5.11(100
REQ
Δ
Δ
Required value of trim-up resistor kΩ]
Nominal value of output voltage [V]
V
Desired (trimmed) output voltage [V].
T-INCR
O
−
-
−
NOM
V
2
, should be connected between the TRIM
O
Vin (+)
ON/OFF
-
Vin (-)
NOM
+
1.225Δ
Δ)V
)
X
O
Semi
100
−
NOM
(Top View)
[kΩ] (1.0V)
Converter
[kΩ] (1.2V)
Q
TM
[%]
−
Family
626
−
SENSE (+)
SENSE (-)
10.22
Vout (+)
Vout (-)
TRIM
18-36 VDC Input; Standard Outputs from 1-12 VDC
[kΩ] (1.5 –12V)
R
T-INCR
Rload
Page 4 of 70
SQ24 Series DC-DC Converter Data Sheet
To decrease the output voltage (Fig. D), a trim resistor,
R
SENSE(-) (Pin 5), with a value of:
where,
and Δ is as 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.
Converters with output voltage 1.2V and 1.0V have specific
trim schematic and equations, to provide the customers with
the flexibility of second sourcing. For these converters, the
last character of part number is “T”. More information about
trim feature, including corresponding schematic portions, 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 over-voltage
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%
V
This equation is applicable for any condition of output
sensing and/or output trim.
R
R
[V
OUT
T-DECR
T
T
OUT
−
−DECR
DECR
Vin
(
NOM
(
+
=
, should be connected between the TRIM (Pin 6) and
)
Fig. D: Configuration for decreasing output voltage.
Fig. C: Configuration for increasing output voltage.
−
)
=
|
511
, or:
V
Δ
Required value of trim-down resistor [kΩ]
OUT
|
−
(
−
10.22
)]
Vin (+)
ON/OFF
Vin (-)
−
[V
SENSE
Semi
(Top View)
(
Converter
+
)
Q
−
TM
Family
V
[kΩ]
SENSE
SENSE (+)
(
SENSE (-)
−
)]
Vout (+)
Vout (-)
(1.0 – 12V)
TRIM
www.power-one.com
≤
V
O
-
NOM
R
T-DECR
X
10%
Rload
[V]
of