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DCH010505D, DCH010505S

DCH010512D, DCH010512S

DCH010515D, DCH010515S

www.ti.com

SBVS073J – NOVEMBER 2006 – REVISED MAY 2020

Product Folder Links: DCH010505D DCH010505S DCH010512D DCH010512S DCH010515D DCH010515S

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Copyright © 2006–2020, Texas Instruments Incorporated

Feature Description (continued)

8.3.1.2 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.

8.3.1.3 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 VRMS or 60 VDC. Ensure that both input and

output voltages maintain normal SELV limits. The isolation test voltage represents a measure of immunity to

transient voltages.

WARNING

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 VRMS 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. Further isolation or insulation systems must form a barrier between these circuits and any user-

accessible circuitry according to safety standard requirements.

8.3.1.4 Isolation Voltage

Hipot test, flash-tested, withstand voltage, proof voltage, dielectric withstand voltage, and isolation test voltage

are all terms that relate to the same thing: a test voltage applied for a specified time across a component

designed to provide electrical isolation to verify the integrity of that isolation. TI’s DCH01 series of dc-dc

converters are all 100% production tested at 3.5 kVDC for 1 second.

8.3.1.5 Repeated High-Voltage Isolation Testing

Repeated high-voltage isolation testing of a barrier component can degrade the isolation capability, depending on

materials, construction, and environment. The DCH01 series of dc-dc converters have toroidal, enameled, wire

isolation transformers with no additional insulation between the primary and secondary windings. While a device

can be expected to withstand several times the stated test voltage, the isolation capability depends on the wire

insulation. Any material, including this enamel (typically polyurethane), is susceptible to eventual chemical

degradation when subject to very-high applied voltages. Therefore, strictly limit the number of high-voltage tests

and repeated high-voltage isolation testing. However, if it is absolutely required, reduce the voltage by 20% from

specified test voltage with a duration limit of 1 second per test.