High isolation transformers suit smart grid applications
A series of high isolation switch mode transformers, which are compatible with the MAXIM MAX253 to power RS-485/RS-232 transceivers, has been released by Pulse Electronics. The PH9185 series of transformers operate in a fixed duty cycle push-pull topology that delivers lower power (up to 3W) from a low voltage source and a working voltage of up to 4000V, with 5000V isolation and only 8mm creepage.
Offered in a standard SMT package, the devices are suitable for use in industrial control systems, building automation, smart grid, surveillance, automotive, renewable energy and aeronautics applications.
The PH9185 transformers, which are RoHS compliant, meet standard EIA481 requirements. The devices have been certified by UL to comply with UL60950-1 2 edition, by CAN/CSA C22.2 NO. 60950-1-07 2 edition, and by TUV to comply with EN61558-1 and EN61558-2-16 with reinforced insulation. 4000Vrms isolation voltage is guaranteed to meet this requirement. The transformers are offered in tape-and-reel packaging. On request, sample quantities are available.
"Pulse's isolation transformers are unique because the customised EP7 platform has a large separation between the core and pin in a surface mount package," said Gerard Healy, Field Application Engineer, Power Division, Pulse Electronics. "For standard SMD platforms (EP and others), the pin is generally close to the core so it's not suitable for high isolation. High isolation transformers tend to be through-hole, with an offset pin, and oversized to meet isolation requirements, so they are relatively large for the low powers they are delivering. Pulse's design provides a large safety separation (8mm creepage distance) between pins without over-sizing the device itself, so it is high isolation and safety agency compliant in a compact surface mount package."