DCM300P280x500A40
The DCM will latch trim behavior at application of VIN (once VIN
exceeds VIN-UVLO+), and persist in that same behavior until loss of
input voltage.
n At application of VIN, if TR is sampled at above VTRIM-DIS, the
module will latch in a non-trim mode, and will ignore the TR
input for as long as VIN is present.
Pin Functions
+IN, -IN
Input power pins. -IN is the reference for all control pins, and
therefore a Kelvin connection for the control signals is
recommended as close as possible to the pin on the package, to
reduce effects of voltage drop due to -IN currents.
n At application of VIN, if TR is sampled at below VTRIM-EN, the TR
will serve as an input to control the real time output voltage,
relative to full load, 25°C. It will persist in this behavior until VIN is
no longer present.
+OUT, -OUT
Output power pins.
If trim is active when the DCM is operating, the TR pin provides
dynamic trim control at a typical 30 Hz of -3dB bandwidth over the
output voltage. TR also decreases the current limit threshold when
EN (Enable)
This pin enables and disables the DCM converter; when held low the
unit will be disabled. It is referenced to the -IN pin of the converter.
The EN pin has an internal pull-up to VCC through a
10 kΩ resistor.
n Output enable: When EN is allowed to pull up above the enable
threshold, the module will be enabled. If leaving EN floating, it is
pulled up to VCC and the module will be enabled.
trimming above VOUT-NOM
.
FT (Fault)
The FT pin provides a Fault signal.
Anytime the module is enabled and has not recognized a fault, the
FT pin is inactive. FT has an internal 499 kΩ pull-up to Vcc, therefore
a shunt resistor, RSHUNT, of approximately 50 kΩ can be used to
ensure the LED is completly off when there is no fault, per the
diagram below.
n Output disable: EN may be pulled down externally in order
to disable the module.
n EN is an input only, it does not pull low in the event of a fault.
Whenever the powertrain stops (due to a fault protection or
disabling the module by pulling EN low), the FT pin becomes active
and provides current to drive an external circuit.
n The EN pins of multiple units should be driven high concurrently
to permit the array to start in to maximum rated load. However,
the direct interconnection of multiple EN pins requires additional
considerations, as discussed in the section on Array Operation.
When active, FT pin drives to VCC, with up to 4 mA of external
loading. Module may be damaged from an over-current FT drive,
thus a resistor in series for current limiting is recommended.
TR (Trim)
The TR pin is used to select the trim mode and to trim the output
voltage of the DCM converter. The TR pin has an internal pull-up to
The FT pin becomes active momentarily when the module starts up.
V
CC through a 10.0 kΩ resistor.
Typical External Circuits for Signal Pins (TR, EN, FT)
Vcc
Vcc
Vcc
Fault
Monitoring
499k
10k
10k
Output Voltage
Reference,
Soft Start and
Fault Monitoring
Current Limit
Reference
and Soft Start Control
FT
TR
EN
SW
RSERIES
RTRIM
RSHUNT
Kelvin -IN connection
DCM™ DC-DC Converter
Rev 1.1
vicorpower.com
800 927.9474
Page 17 of 25
10/2015
VICOR [ VICOR CORPORATION ]
