Digitally controlled 500W AC/DC Supply

Intended primarily as medium power front-end units for distributed power systems, the small physical size and high functionality of Astec NTS503 ac-dc power supplies makes them especially suitable for use in information technology equipment (ITE) and light industrial systems. The power supplies

are also available with medical approvals, for applications such as patient monitoring systems and other portable equipment used in medical wards and surgical operating theatres.



Astec NTS503 ac-dc power supplies generate a tightly regulated 12 V output that can be used to directly power boards fitted with multiple non-isolated point-of-load (POL) dc-dc converters. The convection cooled model can deliver up to 16.6 A, and the forced-air version can deliver up to 41.7 A.

Both versions also provide an auxiliary 'always-on' regulated 5 Vdc @ 2 A output for applications that require standby operation, as well as a 12 V output for powering fans.



Astec NTS503 power supplies feature a universal input that accepts any voltage in the range 85 to 264 Vac at any frequency from 47 to 440 Hz, enabling them to be used in equipment destined for any part of the world. Active power factor correction minimises input harmonic current distortion

and ensures compliance with the international EN61000-3-2 standard. The power supplies employ the latest high frequency switch-mode technology to maximise conversion efficiency, typically achieving 85% at full load with a nominal 115 Vac input.



Built-in control and monitoring features include 'ac power fail' and 'dc OK' output signals and a remote on/off input, and the supplies are comprehensively protected against overvoltage, short-circuit and

overtemperature conditions. Single-wire current sharing is available as standard, and the power supply incorporates an internal Or-ing diode on its main 12 V output, for fault-tolerant and N+1 redundancy applications.



The power supply is digitally controlled and features a PMBus(tm)-compliant I2C interface. This allows monitoring of critical parameters such as temperature, output voltage and current.



The main 12 V output can be adjusted 5% either side of nominal via an internal trim potentiometer or through the digital interface, and regulation is maintained to within ±2% for all line and load conditions. Differential remote sense facilities are provided to compensate for up to 0.5 V drop

between the output terminals and the load. The auxiliary 5 Vdc output is regulated to within ±5% and can deliver up to 2.0 A; it is primarily intended for powering 'standby' circuitry that needs to remain on for most of the time, such as power-up/down sequencers, and is unaffected by the

on/off status of the main 12 V output. The auxiliary 12 V fan output can deliver up to 1 A, or up to 0.5 A on the forced air version, and is present whenever the main 12 V output is on.



Astec NTS503 ac-dc power supplies comply with the rigorous EN55022-B and FCC part 15 Level B EMC standards for conducted noise and meet all applicable immunity standards, including EN61000-4-2, -3, -4, -5, -6 and -11 levels 3. The power supplies carry UL/cUL60950-1 and EN60950-1 VDE safety approvals,

and the medical versions are also approved to UL/cUL60601-1 and VDE EN60601-1.



Sample quantities of Astec NTS503 ac-dc power supplies, including models with medical approvals, are available for immediate delivery. Standard lead-time for both types is stock to 8 weeks. Pricing starts at US$299 for the ITE/industrial models and US$325 for the medical models, in production

quantities.