PQ60033EGX20 Datasheet, PDF (10/13 Pages) SynQor Worldwide Headquarters – Fixed frequency switching provides predictable EMI performance

Technical
Specification
PQ60033EGx20
OUTPUT VOLTAGE TRIM (Pin 6): The TRIM input permits the
user to adjust the output voltage across the sense leads up or
down according to the trim range specifications.
To decrease the output voltage, the user should connect a resistor
between Pin 6 and Pin 5 (SENSE(-) input). For a desired decrease
of the nominal output voltage, the value of the resistor should be
( ) ^Rtrim-down ⁼
511
D%
- 10.22
(kW)
where

D% =
Vnominal – Vdesired
Vnominal
x 100%
To increase the output voltage, the user should connect a resistor
between Pin 6 and Pin 7 (SENSE(+) input). For a desired increase
of the nominal output voltage, the value of the resistor should be
( ) ^{Rtrim-up = 5.11VOUT(100+D%) _ 511 _ 10.22 (kW)}
1.225D%
D%
where
V_OUT = Nominal Output Voltage
Figure C graphs the relationship between the trim resistor value
and Rtrim-up and Rtrim-down, showing the total range the output
voltage can be trimmed up or down.
10,000
1,000
PROTECTION FEATURES
Input Under-Voltage Lockout: The converter is designed
to turn off when the input voltage is too low, helping avoid an
input system instability problem, described in more detail in the
application note titled “Input System Instability” available on the
SynQor website. The lockout circuitry is a comparator with DC
hysteresis. When the input voltage is rising, it must exceed the
typical Turn-On Voltage Threshold value (listed on the specifica-
tion page) before the converter will turn on. Once the converter is
on, the input voltage must fall below the typical Turn-Off Voltage
Threshold value before the converter will turn off.
Output Current Limit: The maximum current limit remains
constant as the output voltage drops. However, once the imped-
ance of the short across the output is small enough to make the
output voltage drop below the specified Output DC Current-Limit
Shutdown Voltage, the converter turns off.
The converter then enters a “hiccup mode” where it repeatedly
turns on and off at a 5 Hz (nominal) frequency with a 5% duty
cycle until the short circuit condition is removed. This prevents
excessive heating of the converter or the load board.
Output Over-Voltage Limit: If the voltage across the output
pins exceeds the Output Over-Voltage Protection threshold, the
converter will immediately stop switching. This prevents damage
to the load circuit due to 1) excessive series resistance in output
current path from converter output pins to sense point, 2) a release
of a short-circuit condition, or 3) a release of a current limit condi-
tion. Load capacitance determines exactly how high the output
voltage will rise in response to these conditions. After 200 ms the
converter will automatically restart.
100
10
1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
% increase Vout
% decrease Vout
Figure C: Trim Graph for 3.3Vout module
Note: the TRIM feature does not affect the voltage at which the
output over-voltage protection circuit is triggered. Trimming the
output voltage too high may cause the over-voltage protection
circuit to engage, particularly during transients.
Over-Temperature Shutdown: A temperature sensor on the
converter senses the average temperature of the module. The ther-
mal shutdown circuit is designed to turn the converter off when the
temperature at the sensed location reaches the Over-Temperature
Shutdown value. It will allow the converter to turn on again when
the temperature of the sensed location falls by the amount of the
Over-Temperature Shutdown Restart Hysteresis value.
It is not necessary for the user to add capacitance at the Trim pin.
The node is internally bypassed to eliminate noise.
Total DC Variation of Vout: For the converter to meet its full
specifications, the maximum variation of the DC value of Vout,
due to both trimming and remote load voltage drops, should not
be greater than that specified for the output voltage trim range.
Product # PQ60033EGx20
Phone [phone]
www.synqor.com
Doc.# 005-0005349 Rev. A
09/23/09
Page 10