Datasheet

rev.
page
date
DESCRIPTION: point of load converter
5 of 10
08/2007
20050 SW 112
th
Ave. Tualatin, Oregon 97062 phone [phone] fax [phone]
PART NUMBER: VPOL5A-5-SIP
5. Main Features and Functions
5.1 Operating Temperature Range
VPOL5A-5-SIP series converters highly efficient converter
design has resulted in its ability to operate over a wide ambient
temperature environment ( -40 to 85 ). Due consideration must
be given to the de-rating curves when ascertaining maximum power
that can be drawn from the converter. The maximum power drawn is
influenced by a number of factors, such as:
Input voltage range.
Output load current.
Air velocity (forced or natural convection).
Mounting orientation of converter PCB with respect to the Airflow.
Motherboard PCB design, especially ground and power planes.
These can be effective heat sinks for the converter.
5.2 Over-Temperature Protection (OTP)
The VPOL5A-5-SIP Series converters are equipped with non-latching
over-temperature protection. A temperature sensor monitors the
temperature of the hot spot (typically, top switch). If
the temperature
exceeds a threshold of 120 C (typical) the converter will shut down,
disabling the output. When the temperature has decreased the
converter will automatically restart.
The over-temperature condition can be induced by a variety of reasons
such as external overload condition or a system fan failure.
5.3 Output Voltage Adjustment
Section 7.8 describes in detail as to how to trim the output voltage with
respect to its set point. The output voltage on all models is trimmable
in the range 0.75 – 3.63 Vdc.
5.4 Safe Operating Area (SOA)
Figure 2 provides a graphical representation of the Safe Operating
Area (SOA) of the converter. This representation assumes ambient
operating conditions such as airflow
are met as per thermal guidelines
provided in Sections 7.2 and 7.3.
Vo
IoIo,CLIo,max
Vo,nom
Safe Operating Area
CURRENT (A)
VOLTAGE (V)
Figure 2. Maximum Output Current Safe Operating Area
5.5 Over Current Protection
All different voltage models have a full continuous short-circuit
protection. The unit will auto recover once the short circuit is removed.
To provide pr otection in a fault condition, the unit is equipped with
internal over-current protection. The unit operates normally once the
fault condition is removed. The power module will supply up to 150% of
rated current. In the event of an over current converter will go into a
hiccup mode protection.
5.6 Remote On/Off
The remote on/off input feature of the converter allows external
circuitry to turn the converter on or off. Active-high remote on/off is
available as sta
ndard. The VPOL5A-5-SIP series converters are t
urned
on if the remote on/off pin is high, or left open or floating. Setting the
pin low will turn the converter off. The signal level of the remote on/off
input is defined with respect to ground. If not using the remote on/off
pin, leave the pin open (module will be on). The part number suffix “N”
is Negative remote on/off version. The unit is guaranteed off over the
full temperature range if this voltage level exceeds 2.8 Vdc. The
converters are turned on If the on/off pin input is low or left open. The
recommended SIP remote on/off drive circuit as shown as figure 3, 4.
Figure 3. Positive Remote on/off Input Drive Circuit
Q1
On/Off
Control
+Vin
Remote On/Off
Common Common
+Vo
SIP Series
Figure 4. Negative Remote On/Off Input Drive Circuit
5.7 UVLO (Under-Voltage Lockout)
The voltage on the Vcc pin determines the start of the operation of the
Converter. When the input Vcc rises and exceeds about 2.0 V the
converter initiates a soft start. The UVLO function in the converter has
a hysterosis (about 100mV) built in to provide noise immunity at start-
up.
Q1
SIP Series
On/Off
Control
+Vin +Vo
Remote On/Off
CommonCommon
CUI INC’s
For more information, please visit the product page.