CLD-AP-76 REV 0

CREE XLAMP XP-E MR16

Cree® XLamp® XP-E MR16 Reference Design

INTRODUCTIONTABLE OF CONTENTS

It is a challenge to design an efficient, high lumen,

Design approach/objectives................................... 2

small form factor, solid-state luminaire at a reasonable

The 6-step methodology........................................ 2

cost. The limited space of an MR16 lamp means that

1. Define lighting requirements.......................... 2

designing the optical, thermal, and electrical compo-

2. Define design goals...................................... 4

nents to achieve the desired requirements is not easy.

3. Estimate efficiencies of the optical, thermal &electrical systems......................................... 4

This application note details the design of an MR16

4. Calculate the numbder of LEDs...................... 9

lamp using Cree’s XLamp XP-E LED. The goal of this

5. Consider all design possibilities.................... 10

design is to develop a replacement 20 W MR16 lamp

6. Complete the final steps: implementation andmeeting the ENERGY STAR requirements. In this refer-analysis.................................................... 10ence design we used simulation and prototype creation

Conclusions....................................................... 15

to build a replacement for the traditional 20 W MR16
halogen bulb. Building on Cree’s reference designs ofprototype MR16 replacement lamps using XLamp MT-Gand XM-L EZW LEDs1, this design provides another possibility to create an LED-based MR16 lamp that exceeds

WWW.CREE.COM/XLAMP

the performance of existing halogen MR16 bulbs.

1

Cree XLamp MT-G MR16 Reference Design, Application Note
AP62
http://www.cree.com/products/pdf/XLampMTG_MR16_Ref.pdf
Cree XLamp XM-L EZW MR16 Reference Design, Application Note
AP71
http://www.cree.com/products/pdf/XLampXML_MR16_ref.pdf
Copyright © 2011 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Creelogo and XLamp are registered trademarks and EasyWhite is a trademark of Cree, Inc. This document is provided for informational
purposes only and is not a warranty or a specification. For product specifications, please see the data sheets available at www.cree.
com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.

Cree, Inc.
4600 Silicon Drive
Durham, NC 27703
USA Tel: +1.919.313.5300

CREE XLAMP XP-E MR16

DESIGN APPROACH/OBJECTIVESIn the “LED Luminaire Design Guide”,2 Cree advocates a 6-step framework for creating LED luminaires. All Cree reference designs use this framework, and the design guide’s summary table is reproduced below.
Step

Explanation

1. Define lighting
requirements• The design goals can be based either on an existing fixture or on the application’s

2. Define design goals• Specify design goals, which will be based on the application’s lighting requirements.
• Specify any other goals that will influence the design, such as special optical or

3. Estimate efficiencies ofthe optical, thermal &electrical systems• Design goals will place constraints on the optical, thermal and electrical systems.
• Good estimations of efficiencies of each system can be made based on these
constraints.
• The combination of lighting goals and system efficiencies will drive the number of LEDs

4. Calculate the number ofLEDs needed• Based on the design goals and estimated losses, the designer can calculate the number

5. Consider all design
possibilities and choose
the best• With any design, there are many ways to achieve the goals.
• LED lighting is a new field; assumptions that work for conventional lighting sources

6. Complete final steps• Complete circuit board layout.
• Test design choices by building a prototype luminaire.
• Make sure the design achieves all the design goals.
• Use the prototype to further refine the luminaire design.
• Record observations and ideas for improvement.

lighting requirements.

environmental requirements.

needed in the luminaire.

of LEDs to meet the design goals.

may not apply.

Table 1: Cree 6-step framework

THE 6-STEP METHODOLOGY
The major goal for this project was to create a 20 W equivalent XLamp XP-E LED-based MR16 lamp. It is meant to be aplug-in replacement for any MR16 fixture and operate with the existing low voltage power supply.

1. DEFINE LIGHTING REQUIREMENTS
Table 2 shows a ranked list of desirable characteristics to address in an MR16 reference design.
Importance

Characteristic

Units

CriticalLight intensity

Center Beam Candle Power (CBCP) candelas (cd)Nominal beam angle

Angle (deg)Electrical power

Watts (W)

Luminous flux

Lumens (lm)Form factor
Important

Price

$

Lifetime

Hours

Operating temperatures

˚C

Operating humidity% RH

Correlated Color Temperature (CCT)K

Color Rendering Index (CRI)

100 point scale

Manufacturability
Ease of installation

Table 2: Ranked design criteria for MR16 replacement lamp
2

LED Luminaire Design Guide, Application Note AP15, www.cree.com/products/pdf/LED_Luminaire_Design_Guide.pdf

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
2

CREE XLAMP XP-E MR16

As a comparison, photometric testing of several halogen MR16 lamps provides basic benchmark data.3
SourceLuminaire Power (W)Luminous Flux (lm)

CBCP (cd)Efficacy (lm/W)

Beam Angle (˚)

CCT (K)

MR16 A

20

2802

420

13.6

36

2900

MR16 B

20

254

455

12

30

2780

MR16 C

20

260

950

12.6

22

2780

Table 3: Halogen MR16 comparison data
The following table summarizes the ENERGY STAR requirements for all integral LED lamps.4
Characteristic

Requirement

CCT

Lamp must have one of the following designated CCTs (per ANSI C78.377-2008) consistent with the 7-step
chromaticity quadrangles and Duv tolerances below.
NominalTarget CCT (K)
Target Duv
CCT (K)and tolerance
and tolerance
2700
2725 + 145
0.000 + 0.006
3000
3045 + 175
0.000 + 0.006
3500
3465 + 245
0.000 + 0.006
4000
3985 + 275
0.001 + 0.006

Color maintenanceThe change of chromaticity over the minimum lumen maintenance test period (6,000 hours) shall be within
0.007 on the CIE 1976 (u’, v’) diagram.

CRI

Minimum CRI (Ra) of 80. R9 value must be greater than 0.

Dimming

Lamps may be dimmable or non-dimmable. Product packaging must clearly indicate whether the lamp is
dimmable or not dimmable. Manufacturers qualifying dimmable products must maintain a web page providing
dimmer compatibility information.

Warranty

3-year warranty

Allowable lamp bases

Must be a lamp base listed by ANSI.

Power factor (PF)Lamp power < 5 W and low voltage lamps: no minimum PF
Lamp power > 5 W: PF > 0.70

Minimum operating temperature-20°C or below

LED operating frequency≥ 120 Hz
Note: This performance characteristic addresses problems with visible flicker due to low frequency operation
and applies to steady-state as well as dimmed operation.
Dimming operation shall meet the requirement at all light output levels.

Electromagnetic and radio
frequency interference

Must meet appropriate FCC requirements for consumer use (FCC 47 CFR Part 15)

Audible noiseClass A sound rating

Transient protection

Power supply shall comply with IEEE C62.41-1991, Class A operation. The line transient shall consist of sevenstrikes of a 100 kHz ring wave, 2.5 kV level, for both common mode and differential mode.

Operating voltage

Lamp shall operate at rated nominal voltage of 120, 240 or 277 VAC, or at 12 or 24 VAC or VDC.

Table 4: ENERGY STAR requirements for integral LED lamps

3

Measured in an integrating sphere at Cree’s facility in Santa Barbara, California

4

ENERGY STAR Program Requirements for Integral Lamps, Eligibility Criteria, Version 1.2, Table 4
http://www.energystar.gov/ia/partners/product_specs/program_reqs/ILL_prog_reqs.pdf

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
3

CREE XLAMP XP-E MR16

The following table summarizes ENERGY STAR requirements for MR16 lamps.5

Characteristic

Requirement

Definition

Directional lamp means a lamp having at least 80% light output within a solid angle of∏ sr (corresponding to a cone with angle of 120˚.

Minimum luminous efficacy

Lamp diameter < 20/8 inch: 40 lm/W
Lamp diameter < 20/8 inch: 45 lm/W

Color spacial uniformity

The variation of chromaticity within the beam angle shall be within 0.006 from theweighted average point on the CIE 1976 (u’, v’) diagram.

Maximum lamp diameter

Not to exceed target lamp diameter as per ANSI C78.21-2003.

Maximum overall length (MOL)

Not to exceed MOL for target lamp as per ANSI C78.21-2003.

Minimum center beam intensity

473 cd - determined from the ENERGY STAR® Integral LED Lamp Center Beam
Intensity Benchmark Tool (ed. 7/6/2010)

Lumen maintenance

L70 > 25,000 hours

Rapid-cycle stress test

Cycle times must be 2 minutes on, 2 minutes off. Lamp will be cycled once for every 2hours of required minimum L70 life.

Table 5: ENERGY STAR requirements for MR16 lamps

2. DEFINE DESIGN GOALS
The design goals for this project as derived from the information above:

Characteristic

Unit

Light output

Lm

Illuminance profile

Minimum Goal

Target Goal

210

> 210

Identical

Power

W

<< 10

3.5

Beam angle

˚

36

36

CBCP

Cd

473

> 473

Luminaire efficacy

lm/W

> 50

60

Lifetime

Hours

50,00050,000

K

3000

3000

> 80

80

30

40

CCT
CRI
Maximum ambient temperature

˚C

Table 6: Design goals

3. ESTIMATE EFFICIENCIES OF THE OPTICAL, THERMAL & ELECTRICAL SYSTEMS
Component Efficiency
Considering efficiency, stability, cost, availability of secondary optics, color rendering and LM-80 availability, two LEDs
from the XP family became candidates: the XLamp XP-E and XP-G, highlighted in yellow in Figure 2. The XP-E has aslight advantage due to its lower cost.

5

Ibid, Table 7C

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
4

CREE XLAMP XP-E MR16

Figure 2: Binning comparison(left: XP-E, right: XP-G)
Cree chose to work with the XPEWHT-H1-0000-00AE7, highlighted in yellow in Figure 3, in this reference design.

Figure 3: XP-E color, bin and order code
The XLamp XP-E LED has completed LM-80 testing, fulfilling ENERGY STAR’s requirement. The XP-E has been in volume
production for over two years and has become the workhorse of many LED luminaires. It is a reliable choice for an MR16
retrofit lamp.

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
5

CREE XLAMP XP-E MR16

Thermal Requirements
Despite the XLamp XP-E LED’s efficacy advantage over conventional incandescent and fluorescent lighting, as much as
80% of the input power is converted to heat. This heat needs to be dissipated efficiently to ensure LED and luminaire
lumen maintenance and reliability. For a 4 W MR16 luminaire, there are many existing market thermal solutions fromwhich to choose. For this reference design, Cree selected an existing well-designed machined aluminum heat sink withgood workmanship. Our simulations and actual test results confirmed this as a good choice for this project.

Figure 4: Machined aluminum heat sinkCree performed thermal simulation6 on the design with 3 XP-E LEDs running at both 350 mA and 700 mA and found theestimated solder point temperature to be 53˚C. Figure 5 shows the thermal simulation of the solder point temperature.
Figure 6 shows the thermal simulation of the airflow, in the form of convection currents, around the XP-E MR16 lamp.

Figure 5: Thermal simulation oftemperature of XP-E MR16
6

Figure 6: Thermal simulation of
airflow around XP-E MR16

Cree used NIKA EFD Pro V8.2 with Pro E Wildfire
http://www.mentor.com/products/mechanical/products/floefd/
http://www.ptc.com/products/creo-elements-pro/

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
6

CREE XLAMP XP-E MR16

Figure 7 shows the thermocouple attached to the XP-E MR16 lamp to record the solder point temperature. Figure 8
shows the measurement in progress and the temperature reading. The steady-state measurement of 60˚C is a reasonable match to the thermal simulation.

Figure 7: Thermocouple attachedto XP-E LED

Figure 8:XP-E MR16 solder point temperature
measurement

Based on Cree’s experience with the XLamp XP-E LED and the L70 lifetime projection shown in Figure 9, we expect thisdesign to attain both an ENERGY STAR compliant L70 rating of 25,000 hours and meet the target design goal of an L70
rating of 50,000 hours.

Current

Ta/Tsp (ºC)

350 mA85

L70 (hours)
96,294400 mA*85

90,234*500 mA*85

79,234*600 mA*85

69,575*700 mA

85

61,094* Interpolated values

Figure 9: XP-E L70 lifetime estimate
Driver Electronics
Considering the traditional MR16 power requirement and for ease of retrofit, we chose to use a GU5.3 bi-pin connector
with 12 VDC and 12 VAC power input. The LEDs were connected in series to achieve a higher overall Vf for better driverefficiency and to provide the constant drive current required by the LEDs to achieve consistent light output.
To meet the challenge of fitting a high-efficiency driver into the compact space of an MR16 lamp base, a non-dimmable
driver with simple circuit design7 was used, shown in Figure 10.
7

Driver from Shen Zhen IPOWER Electronic Technology Co., Ltd.

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
7

CREE XLAMP XP-E MR16





















 ℃









 ℃



﹣



































Figure 10: XP-E MR16 driver circuit design
Figure 11 shows the XP-E MR16 driver and GU5.3 connector.

Figure 11: XPE-MR16 driver and GU5.3 connector
Secondary Optics
Cree’s XLamp XP-E LED has been in volume production since2009 and many market-ready optics designs are available. Con-TIR

sidering efficiency, beam angle, size and repeatability, Cree chose
to use Total Internal Refraction (TIR) optics for this application.

Figure 12: Example TIR optics

http://www.ipower-tek.com/en/products_01.asp?Cid=55

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
8

CREE XLAMP XP-E MR16

A well-designed TIR optic provides high optical efficiency, a narrow beam angle and good color mixing. As shown in Figure 13,
some designs use surface texture or “mini-pillows” on the lenssurface for color mixing to improve the color uniformity of thelight beam.

Figure 13: Example “mini-pillow” TIR optic
Cree Proprietary — CONFIDENTIAL

Figure 14 shows the secondary optics for the XP-E MR16.

Figure 14: Secondary TIR optics for XP-E MR16

4. CALCULATE THE NUMBDER OF LEDS
The XLamp XP-E LED offers various efficacies depending on color temperature, bin and drive conditions. Based on theelectrical data and optical output from Cree’s Product Characterization Tool (PCT),8 we chose to work with the Q2 flux
bin at 3000K CCT, highlighted in yellow in Figure 15 below, to give a close color point to a halogen bulb. The PCT data
indicate that an MR16 lamp containing 3 XP-E LEDs is capable of meeting the design goals.

8

The analysis came from Cree’s Product Characterization Tool. http://pct.cree.com/

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
9

CREE XLAMP XP-E MR16

Compare:System:SYS # LED

11 SYS lm tot 13 SYS W

Target Lumens :Current Display Range:

12 SYS lm/W 15
Optical Efficiency:

210

Current (A)LED 1Cree XLamp
20XP-E {CW/NW/WW}

Flux

Q2 [87.4]

Price

$

5

87.4
Tsp (ºC) 2.0

LED Multiple
SYS # LED SYS lm tot

SYS W

3

94%

LED 2

Model

-

Medium (0.1A - 2.0A)

Electrical Efficiency:

90%

55
x1

1

SYS lm/W

LED 3

Model

Cree XLamp
22XP-G {CW/NW/WW}

Flux

Q2 [87.4]

Price

$

3

-

Tsp (ºC) 2.0

SYS W

Price

55
x1

1

(none)Flux

87.4

LED Multiple
SYS # LED SYS lm tot

Model

1
$

1

LED Multiple

SYS lm/W

10
233
3.09
75.4
10
215
2.87
74.9
#N/A
#N/A
7
236.6
3.28
72.1
7
225.4
3.05
73.9
#N/A
#N/A
5
218.5
3.14
69.6
5
213
2.98
71.5
#N/A
#N/A
4
213.2
3.19
66.8
4
210.8
3.02
69.8
#N/A
#N/A
4
250
3.87
64.6
4
250.4
3.66
68.4
#N/A
#N/A
3
213.9
3.41
62.7
3
216.6
3.26
66.4
#N/A
#N/A
3
239.1
3.96
60.4
3
244.5
3.77
64.9
#N/A
#N/A
3
263.1
4.5
58.5
3
271.8
4.28
63.5
#N/A
#N/A
3
285.6
5.04
56.7
3
298.5
4.82
61.9
#N/A
#N/A
3
307.2
5.59
55
2
216.2
3.55
60.9
#N/A
#N/A
2
218.6
4.09
53.4
2
233
3.94
59.1
#N/A
#N/A
2
231.4
4.45
52
2
249.2
4.3
58
#N/A
#N/A
2
243.6
4.83
50.4
2
265
4.66
56.9
#N/A
#N/A
2
254.8
5.19
49.1
2
280
5.04
55.6
#N/A
#N/A
2
265.6
5.55
47.9
2
294.8
5.4
54.6
#N/A
#N/A
2
275.6
5.91
46.6
2
308.8
5.81
53.1
#N/A
#N/A
2
284.8
6.28
45.4
2
322.8
6.19
52.1
#N/A
#N/A
2
293.2
6.64
44.2
2
335.8
6.57
51.1
#N/A
#N/A
2
301.2
6.98
43.2
2
348.6
6.96
50.1
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
2
372.8
7.74
48.2
#N/A
#N/A
Figure 15: Cree’s
Product
Characterization
Tool
with
XLamp
XP
data
#N/A
#N/A
#N/A
#N/A
2
395
8.51
46.4
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
2
415.2
9.3
44.6
#N/A
#N/A
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.500
0.550
0.600
0.650
0.700
0.750
0.800
0.850
0.900
0.950
1.000
1.100
1.200
1.300

5. CONSIDER ALL DESIGN POSSIBILITIESDue to the vast quantity of LED-based MR16 designs and parts available in the market, our team tried a number of
combinations of heat sinks, optics, and driver solutions and finally chose to use an MR16 kit from Shenzhen Zhongke
Lianhe Super-Conduction Technology Co. An optic, metal core printed circuit board (MCPCB), heat sink and GU5.3 plug
are included in this kit.

6. COMPLETE THE FINAL STEPS: IMPLEMENTATION AND ANALYSIS
With the methodology above, we determined a suitable combination of XLamp XP-E LEDs, components and drive conditions. This section illustrates the techniques Cree used to create an MR16 replacement based on the design and compares the results with our goal, to create a 20 W XP-E MR16 replacement lamp.

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
10

CREE XLAMP XP-E MR16

Prototyping Details
1.

We verified the component dimensions to ensure a correct fit.

Figure 16: XP-E MR16 components
2.

Following the XLamp XP-family recommendations9, we reflow soldered the XP-E LEDs onto the MCPCB with an appropriate solder paste and reflow profile and cleaned the flux residue with isopropyl alcohol.

3.

We applied a thin layer of thermal conductive compound to the back of the MCPCB and secured the MCPCB to theheat sink with screws.

4.

We inserted the driver into the GU5.3 plug end and soldered the DC output wires to the corresponding terminals
on the MCPCB.

5.

We connected the GU5.3 plug end to the heat sink and secured it with screws. We verified that the MCPCB andplug end were secure.

6.

We inserted the TIR optics, ensuring proper alignment to the LEDs. Depending on the type of TIR optics and theirdesign, various securing options can be used including self locking, additional locking ring, or adhesive.

7.

We tested the completed assembly with 12 VDC.

Results
Optical Results
Optical testing of the XLamp XP-E MR16 shows this reference design meets the target specifications. Contour plots ofcolor and luminance distribution of the reference design10 are shown below in Figure 17 and Figure 18. These demonstrate that the TIR optics evenly distribute the light from the 3 XP-E LEDs and produce smooth light without hotspots.
9“Cree XLamp XP Family Soldering & Handling”
http://www.cree.com/products/pdf/XLampXP_SolderingandHandling.pdf

10

Plots were taken with Radiant Imaging’s imaging photometer.
http://www.radiantimaging.com

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
11

CREE XLAMP XP-E MR16

Figure 17: Contour plot of CCT color distribution (oval shape is a result of off-axis camera placement)

Figure 18: Contour plot of luminance distribution (oval shape is a result of off-axis camera placement)

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
12

CREE XLAMP XP-E MR16

As shown in Figure 19 and Figure 20, the XLamp XP-E MR16 lamp far field distribution pattern betters that of two halogen MR16 bulbs.
-180
180-174-168168 174
600.00
-162
162
-156
156
-150
150
-144
500.00
144
-138
138
-132
400.00
132
-126
126
-120
300.00
120
-114
114
-108
200.00108-102
102100.00
-96
96
-90
0.00
90
-84
84
-78
78
-72
72
-66
66
-60
60
-54
54
-48
48
-42
42
-36
36
-30
XPE 20W MR16
30
-24
24
-18
Halogen MR16 - A
18 12
-12
6
0 -6
Halogen MR16 - B

Figure 19: Goniometric intensity polar plot comparison of 20 W equivalent XP-E MR16

600
550

XPE 20W MR16500

Halogen MR16 - A

Lum Intensity (Cd)450

Halogen MR16 - B

400
350
300
250
200
150
100
50

1

0
-90 -80 -70 -60 -50 -40 -30 -20 -10 0

10 20 30 40 50 60 70 80 90

Angle (deg)Figure 20: Measured luminous intensity comparison of 20 W equivalent XP-E MR16

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
13

CREE XLAMP XP-E MR16

Figure 21 shows the illuminance of the XLamp XP-E MR16 lamp at various distances from the light source. The beam
angle is 35 degrees.
HeightIlluminanceDiameter

1m

3.2 ft47.3 fc

508.6 lx

63.1 cm

2.1 ft2m

6.6 ft11.8 fc

127.2 lx

126.1 cm

4.1 ft3m

9.8 ft5.2 fc56.5 lx

189.2 cm

6.2 ft4.m

13.1 ft

3.0 fc31.8 lx252.2 cm

8.3 ft5m

16.4 ft

1.9 fc20.4 lx

315.3 cm

10.3 ft

6m

19.7 ft

1.3 fc14.1 lx378.4 cm

12.4 ft

7m

23.0 ft.9 fc

10.3 lx

441.4 cm

14.5 ft

8m

26.2 ft.7 fc

8.0 lx504.5 cm

16.6 ft

9m

29.5 ft.6 fc

6.3 lx567.5 cm

18.6 ft

10 m

32.8 ft.5 fc

5.1 lx630.6 cm

20.7 ft

Figure 21: XP-E MR16 illuminance
Table 7 summarizes the results and shows that the XP-E MR16 lamp generally meets the design goals and betters theperformance of comparison halogen fixtures.

Characteristic

Unit

ResultTarget Goal

Light output (10 min. on time)

lm

209

> 210

Power

W

3.6

3.5

Beam angle

Deg

36

36

CBCP

Cd

508

> 473

Efficacy

lm/W

58

60

Lifetime

Hours

50,00050,000

K

3000

3000

> 80

80

30

40

CCT
CRI
Maximum ambient temperature

˚C

Table 7: XLamp XP-E MR16 test results

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
14

CREE XLAMP XP-E MR16

CONCLUSIONS
The intent of this design is to demonstrate that Cree’s high-power XLamp XP-E LED can be easily incorporated into a
MR16 retrofit lamp meeting the ENERGY STAR requirements. Testing of the prototype shows that this goal has been met.
Despite the “plug and play” nature of this design, there are many improvements a committed design team with appropriate resources can make, such as a simpler and cheaper heat sink and a dimmable power supply. This design shows
the level of performance that can be achieved with the Cree XLamp XP-E LED but should not be interpreted as the only
way that a good XP-E LED-based MR16 lamp can be designed.

Copyright © 20112010 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks
andEasyWhite
is a trademark of Cree, Inc. This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, pleaseof Cree,Inc.
see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at sales@cree.com. Other trademarks, product and company names are theproperty of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association.
15