DCV01 Series

SBVS014A – AUGUST 2000 – REVISED DECEMBER 2013

www.ti.com

PCB LAYOUT

RIPPLE AND NOISE

Careful consideration should be given to the layout of the PCB in order that the best results can be obtained.

The DCV01 is a switching power supply, and as such, can place high peak-current demands on the input supply.

In order to avoid the supply falling momentarily during the fast switching pulses, ground and power planes should

be used to track the power to the input of the DCV01. If this is not possible, then the supplies must be connected

in a star formation with the tracks made as wide as possible.

ground) around this pin to avoid any noise pick up.

The output should be taken from the device using ground and power planes; this will ensure minimum losses.

A good quality low-ESR capacitor placed as close as practicable across the input will reduce reflected ripple and

ensure a smooth start up.

A good quality low-ESR capacitor placed as close as practicable across the rectifier output terminal and output

ground will give the best ripple and noise performance.

THERMAL MANAGEMENT

Due to the high power density of this device, it is advisable to provide ground planes on the input and output.

ISOLATION

Underwriters Laboratories, UL™ defines several classes of isolation that are used in modern power supplies.

Safety Extra Low Voltage (SELV) is defined by UL (UL1950 E199929) as a secondary circuit which is so

designated and protected that under normal and single fault conditions the voltage between any two accessible

parts, or between an accessible part and the equipment earthing terminal for operational isolation does not

exceed steady state 42V peak or 60VDC for more than 1 second.

DCH, DCP, DCR, and DCV Series DC-DC Converters

TI’s DCH, DCP, DCR, and DCV (DCx) series dc-dc converters are specified for operational isolation only.

Operation or Functional Isolation

Operational or functional isolation is defined by the use of a hipot test only. Typically, this isolation is defined as

the use of insulated wire in the construction of the transformer as the primary isolation barrier. The hipot one-

second duration test (dielectric voltage, withstand test) is a production test used to verify that the isolation barrier

is functioning. Products with operational isolation should never be used as an element in a safety-isolation

system.

Basic or Enhanced Isolation

Basic or enhanced isolation is defined by specified creepage and clearance limits between the primary and

secondary circuits of the power supply. Basic isolation is the use of an isolation barrier in addition to the insulated

wire in the construction of the transformer. Input and output circuits must also be physically separated by

specified distances.

Continuous Voltage

For a device that has no specific safety agency approvals (operational isolation), the continuous voltage that can

be applied across the part in normal operation is less than 42.4 V peak, or 60 VDC; that is, both input and output

should normally be maintained within SELV limits. The isolation test voltage represents a measure of immunity to

transient voltages; do not use the device as an element of a safety isolation system when SELV is exceeded. If

the device is expected to function correctly with more than 42.4 V peak or 60 VDC applied continuously across

the isolation barrier, then the circuitry on both sides of the barrier must be regarded as operating at an unsafe

voltage, and further isolation or insulation systems must form a barrier between these circuits and any user-

accessible circuitry according to safety standard requirements.

10

Submit Documentation Feedback

Copyright © 2000–2013, Texas Instruments Incorporated