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Mean Well LOP-400-27 400W 5"×3" Low Profile Open Frame Power Supply 27V 9.3A

conventional 250W400W if using fanhigh frequency up to 94%

SKU LOP-400-27

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Overview

LOP-400-27 is the 27V output model of this series: typical efficiency 95%.

The LOP-400 is a 400W highly reliable, energy-efficient, low-profile open frame type power supply. With a high power density of 24.6W/in³ within the standard size of 5" x 3", it features a universal input voltage range of 80~264VAC, making it suitable for global applications. The series offers a comprehensive selection of standard voltages, including 12V/15V/18V/24V/27V/36V/48V/54V, and comes in a complete range of models. The main features of the LOP-400 include: low standby power (<0.5W), high efficiency (up to 95%), capable of providing 250W under natural air cooling and 400W with an additional fan. It has a 150% @ 3 seconds overload capacity, a wide operating temperature range of -40 to +80℃, compliance with OVC III, suitable for Class I (with FG) or Class II (without FG) systems. The product has obtained multiple safety certifications, including 62368-1/60601-1/61558-1/60335-1, and is designed to meet 2xMOPP and extremely low touch leakage current <70 μ A, making it suitable for BF class medical devices. With high product safety and excellent EMC performance, it is versatile and applicable in various fields such as ITE, medical, industrial control, home automation and more. It is a cost-effective slim open frame type power supply.

Features

MEAN WELL Patent Number: ZL 202223277512.1
5"×3" compact size with low profile (27.5mm)
80~264Vac input with PFC, No load power consumption<0.5W
Global certificates in multi-fields (ITE 62368-1, Medical 60601-1, Household 60335-1, Industrial 61558-1/-2-16)
150%peak load @ 3s
250W convection, 400W with FAN 23CFM
Suitable for Class Ⅰor Class Ⅱ installations
Over voltage category Ⅲ (OVC Ⅲ)
-40 ~ +80℃ wide range operation temperature
High efficiency up to 95%
Protections: Short circuit / Overload / Over voltage / Over temperature
Extremely low leakage current, 2 x MOPP, suitable for BF medical applications
Operating altitude up to 5000 meters
Built-in 12V/0.5A for external FAN
Built-in Remote sense
3 years warranty

Specifications

LOP-400-27Specifications from the official datasheet (2026-06-17 edition)

OUT PUT

DC VOLTAGE: 27V
CURRENT Peak(3sec.): 22.2A
CURRENT 23CFM: 14.9A
CURRENT Convection: 9.3A
RATED POWER Peak(3sec.): 599.4W
RATED POWER 23CFM: 402.3W
RATED POWER Convection: 251.1W
RIPPLE & NOISE (max.)^Note.2: 200mVp-p
VOLTAGE ADJ. RANGE (MAIN OUTPUT): 25.6 ~ 28.4V
VOLTAGE TOLERANCE^Note.3: ±1.0%
LINE REGULATION: ±0.5%
LOAD REGULATION: ±1.0%
SETUP, RISE TIME: 1000ms, 30ms/230Vac 1500ms, 30ms/115Vac at full load
HOLD UP TIME (Typ.): 30ms@250W load , 16ms@400W load

INPUT

VOLTAGE RANGE^Note.4: 80 ~ 264Vac 113 ~ 370Vdc
FREQUENCY RANGE: 47 ~ 63Hz
POWER FACTOR: PF>0.95/230Vac PF>0.98/115Vac at full load
EFFICIENCY (Typ.): 95%
AC CURRENT (Typ.): 4.2A/115Vac 2.1A/230Vac
INRUSH CURRENT (Typ.): COLD START 40A/115Vac 80A/230Vac
LEAKAGE CURRENT: ClassⅠ: Earth leakage current < 500 μA (rms) @ 264V ac , touch current < 70μA (rms) @ 264V ac ClassⅡ: Touch current < 100 μA (rms) @ 264V ac

PROTECTION

OVERLOAD: 105 ~ 150% rated output power, Protection type : Hiccup after 3 sec, recovers automatically after fault condition is removed
OVER VOLTAGE: 29.7 ~ 35.1V Protection type : Shut down o/p voltage, re-power on to recover
OVER TEMPERATURE: Protection type : Shut down o/p voltage, recovers automatically after temperature goes down or re-power on to recover

FUNCTION

EXTERNAL FAN SUPPLY: 12V@0.5A for driving a fan (23CFM) / 12V@0.2A for without fan ; Tolerance -15% ~+15% at main output 20% rated current
REMOTE SENSE: The remote sensing compensates voltage drop on the load wiring up to 0.5V
POWER GOOD / POWER FAIL (optional): 500ms>PG>10ms ; The TTL signal goes high with 10ms to 500ms delay after power set up ; The TTL signal goes low at least 1ms before Vo below 90% of rated value ; TTL(0 ~ 1V), TTH(2 ~ 5V)

ENVIRONMENT

WORKING TEMP.: -40 ~ +80℃ (Refer to "Derating Curve")
WORKING HUMIDITY: 20 ~ 90% RH non-condensing
STORAGE TEMP., HUMIDITY: -40 ~ +85℃, 10 ~ 95% RH non-condensing
TEMP. COEFFICIENT: ±0.03%/℃ (0 ~ 50℃)
VIBRATION: 10 ~ 500Hz, 2G 10min./1cycle, 60min. each along X, Y, Z axes

SAFETY & EMC

SAFETY STANDARDS^Note.5: CB IEC62368-1, IEC60335-1, IEC61558-1/-2-16, IEC60601-1; TUV BS EN/EN62368-1, BS EN/EN60335-1, BS EN/EN61558-1/-2-16, BS EN/EN60601-1(3.2 Version); UL UL62368-1, ANSI / AAMI ES60601-1(3.2 Version) ; CCC GB4943.1 ; RCM AS/NZS 61558-1/-2-16; EAC TPTC 004 approved.
ISOLATION RESISTANCE: Primary-Secondary: 2xMOPP, Primary-Earth:1xMOPP, Secondary-Earth:1xMOPP
OVER VOLTAGE CATEGORY: IEC/EN 61558-1/-2-16(OVC Ⅲ, altitude up to 2000M ) IEC/EN/UL 62368-1 (OVC Ⅱ, altitude up to 5000M ) IEC/EN 60335-1 (OVC Ⅱ, altitude up to 5000M ) IEC/EN 60601-1 (OVC Ⅱ, altitude up to 4000M )
PROTECTIVE EXTRA-LOW VOLTAGE: IEC/EN61558-2-16 (SELV, 12~48V ) IEC/EN/UL 62368-1 (SELV / ES1, 12~48V )
WITHSTAND VOLTAGE: I/P-O/P:4KVac I/P-FG:2KVac O/P-FG:1.5KVac
ISOLATION RESISTANCE: I/P-O/P, I/P-FG, O/P-FG:100M Ohms / 500VDC / 25℃/ 70% RH
EMC EMISSION: Parameter Standard Test Level

Conducted & Radiated BS EN/EN55032(CISPR32) BS EN/EN55011(CISPR11) ClassⅠ: Class B , Class Ⅱ: Class A
Conducted & Radiated BS EN/EN55014(CISPR32) ClassⅠ: Class B
Harmonic Current BS EN/EN61000-3-2 Class A
Voltage Flicker BS EN/EN61000-3-3
EMC IMMUNITY: BS EN/EN55035,BS EN/ EN61000-6-2

Parameter Standard Test Level

ESD BS EN/EN61000-4-2 Level 4, 15KV air; Level 4, 8KV contact
Radiated Susceptibility BS EN/EN61000-4-3 Level 3, 10V/m( 80MHz~2.7GHz ) Table 9, 9~28V/m( 385MHz~5.78GHz )
EFT/Burest BS EN/EN61000-4-4 Level 3, 2KV
Surge BS EN/EN61000-4-5 Level 4, 4KV/Line-FG; 2KV/Line-Line
Conducted BS EN/EN61000-4-6 Level 3, 10V
Magnetic Field BS EN/EN61000-4-8 Level 4, 30A/m
Voltage Dips and interruptions BS EN/EN61000-4-11 ＞95% dip 0.5 periods, 100% dip 1 periods, 30% dip 25 periods, ＞95% interruptions 250 periods

Parameter	Standard	Test Level
Conducted & Radiated	BS EN/EN55032(CISPR32) BS EN/EN55011(CISPR11)	ClassⅠ: Class B , Class Ⅱ: Class A
Conducted & Radiated	BS EN/EN55014(CISPR32)	ClassⅠ: Class B
Harmonic Current	BS EN/EN61000-3-2	Class A
Voltage Flicker	BS EN/EN61000-3-3

Parameter	Standard	Test Level
ESD	BS EN/EN61000-4-2	Level 4, 15KV air; Level 4, 8KV contact
Radiated Susceptibility	BS EN/EN61000-4-3	Level 3, 10V/m( 80MHz~2.7GHz ) Table 9, 9~28V/m( 385MHz~5.78GHz )
EFT/Burest	BS EN/EN61000-4-4	Level 3, 2KV
Surge	BS EN/EN61000-4-5	Level 4, 4KV/Line-FG; 2KV/Line-Line
Conducted	BS EN/EN61000-4-6	Level 3, 10V
Magnetic Field	BS EN/EN61000-4-8	Level 4, 30A/m
Voltage Dips and interruptions	BS EN/EN61000-4-11	＞95% dip 0.5 periods, 100% dip 1 periods, 30% dip 25 periods, ＞95% interruptions 250 periods

OTHERS

MTBF: 1696.4K hrs min. Telcordia SR-332 (Bellcore) ; 231.2K hrs min. MIL-HDBK-217F (25℃)
DIMENSION: 127*76.2*27.5mm (L*W*H)
PACKING: 0.39Kg; 24pcs/11.5Kg/1.0CUFT

Test conditions and notes5

1. All parameters NOT specially mentioned are measured at 230VAC input, rated load and 25℃of ambient temperature.
2. Ripple & noise are measured at 20MHz of bandwidth by using a 12" twisted pair-wire terminated with a 0.1μF & 47μF parallel capacitor.
3. Tolerance : includes set up tolerance, line regulation and load regulation.
4. Derating may be needed under low input voltages. Please check the derating curve for more details.
5. The power supply is considered a component which will be installed into a final equipment. All the EMC tests are been executed by mounting the unit on a 360mm*360mm metal plate with 1mm of thickness. The final equipment must be re-confirmed that it still meets EMC directives. For guidance on how to perform these EMC tests, please refer to “EMI testing of component power supplies.” (as available on https://www.meanwell.com//Upload/PDF/EMI_statement_en.pdf)

Technical drawings

LOP-400-27 Block Diagram (2) — Block Diagram (2)

LOP-400-27 Derating Curve — Derating Curve

LOP-400-27 Output Derating VS Input Voltage — Output Derating VS Input Voltage

LOP-400-27 LOP-400 series — LOP-400 series

Typical applications

Industrial automation machinery/ control system
Security system
Mechanical and electrical equipment
Electronic instruments, equipments or apparatus
Network equipment
Telecom devices
Power sourcing equipment of PoE
Home automation
Medical devices

Downloads

Datasheet1

LOP-400-27 datasheetLOP_400_spec.pdf · 2026-06-17 edition PDF Download

FAQ

What type of power supply is the Mean Well LOP-400-27?

The Mean Well LOP-400-27 is a 400W low profile open frame AC/DC power supply. It provides a 27V DC output and is built in a compact 5 x 3 inch form factor with a 27.5mm height. This model is intended for embedded OEM and industrial-style equipment where space is limited.

What input range does the LOP-400-27 support?

This model accepts a wide 80 to 264VAC input range and also supports 113 to 370VDC input. It includes active power factor correction, with power factor listed above 0.95 at 230VAC and above 0.98 at 115VAC at full load. That broad input range makes it suitable for equipment intended for global markets.

How much power can the LOP-400-27 deliver under different cooling conditions?

The LOP-400-27 is rated for up to 400W when used with 23CFM forced-air cooling. Under convection cooling, the product description lists 250W output. It also supports 150% peak load for up to 3 seconds, which can help with short-duration load surges.

Is the LOP-400-27 suitable for medical or safety-critical equipment designs?

This model includes IEC60601-1 and ANSI/AAMI ES60601-1 approvals and its primary-to-secondary isolation is rated 2 x MOPP, with low leakage current. Buyers should still confirm the full end-equipment compliance requirements for their specific device.

What protections are included in the Mean Well LOP-400-27?

The LOP-400-27 includes overload, over voltage, and over temperature protection. Overload protection is specified at 105 to 150% of rated output power with hiccup behavior after 3 seconds and automatic recovery after the fault is removed. Over-voltage and over-temperature protection use shutdown behavior, with recovery depending on conditions described in the specification.

Can the LOP-400-27 operate in harsh temperature or high-altitude environments?

This power supply is rated for operation from -40C to +80C, with derating referenced in the product data. Its overvoltage category rating under IEC/EN/UL 62368-1 applies up to 5000 meters altitude (4000 meters under IEC/EN 60601-1). Those ratings make it a strong candidate for demanding industrial and enclosed equipment environments, subject to overall system thermal design.

What certifications and standards does the LOP-400-27 support?

The listed safety standards include IEC62368-1, IEC60335-1, IEC61558-1/-2-16, and IEC60601-1, along with approvals from TUV, UL, CCC, RCM, and EAC. These standards cover ITE, medical, household, and industrial categories. This broad certification profile can simplify sourcing for manufacturers serving multiple regulated markets.

Payment & Security

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Model	Power	Voltage	Current
Mean Well LOP-400-54 400W 5"×3" Low Profile Open Frame Power Supply 54V 4.75A	256.5W	54V	4.75A	View
Mean Well LOP-400-48 400W 5"×3" Low Profile Open Frame Power Supply 48V 5.3A	254.4W	48V	5.3A	View
Mean Well LOP-400-36 400W 5"×3" Low Profile Open Frame Power Supply 36V 7.1A	255.6W	36V	7.1A	View
Mean Well LOP-400-24 400W 5"×3" Low Profile Open Frame Power Supply 24V 10.5A	252W	24V	10.5A	View
Mean Well LOP-400-18 400W 5"×3" Low Profile Open Frame Power Supply 18V 13.9A	250.2W	18V	13.9A	View
Mean Well LOP-400-15 400W 5"×3" Low Profile Open Frame Power Supply 15V 16.7A	250.5W	15V	16.7A	View
Mean Well LOP-400-12 400W 5"×3" Low Profile Open Frame Power Supply 12V 20.8A	249.6W	12V	20.8A	View

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