View EL7900ILCZ-EVALZ_4862678.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

(R)
EL7900
Data Sheet September 18, 2009 FN7377.8
Ambient Light Photo Detect IC
The EL7900 is a light-to-current optical sensor combining a photodiode and a current amplifier on a single monolithic IC. Output current is directly proportionate to the light intensity on the photodiode. Its sensitivity is superior to that of a phototransistor and exhibits little variation. Its spectral sensitivity matches closely to the luminous efficiency and linearity. Housed in an ultra-compact surface mount clear plastic package, this device is excellent for power saving control function in cell phones, PDAs, and other handheld applications.
Features
* Monolithic IC containing photodiode and amplifier * 1lux to 8,000lux range * Converts light intensity to current * 2.7V to 5.5V supply range * Low supply current: 1A * Fast response time - <200s * Excellent output linearity of luminance * Ultra-compact and light surface mount package * Pb-free (RoHS compliant)
Pinout
EL7900 (5 LD ODFN) TOP VIEW
VCC 1 GND 2 EN 3
THERMAL PAD
Applications
* Mobile phones * Notebook PCs
5 OUTPUT
* PDAs * Video cameras
4 NC
* Digital cameras
Ordering Information
PART NUMBER (Note) EL7900ILCZ EL7900ILCZ-T7* TEMP RANGE (C) -40 to +85 -40 to +85 PACKAGE (Pb-Free) 5 Ld ODFN PKG. DWG. # L5.2x2.1
5 Ld ODFN L5.2x2.1 Tape and Reel
EL7900ILCZ-EVALZ Evaluation Board *Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate - e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright (c) Intersil Americas Inc. 2005-2008. All Rights Reserved. All other trademarks mentioned are the property of their respective owners.
EL7900
Absolute Maximum Ratings (TA = +25C)
Supply Voltage between VSD and GND . . . . . . . . . . . . . . . . . . . .6V Maximum Continuous Output Current . . . . . . . . . . . . . . . . . . . . 6mA ESD Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV
Thermal Information
Thermal resistance (Typical, Note 1) JA (C/W) ODFN Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . +90C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-40C to +100C Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . .see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . .-40C to +85C
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
NOTE: 1. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with "direct attach" features. See Tech Brief TB379
Electrical Specifications
PARAMETER VDD ICC1 ICC2 IL1 IL2 ILEAK VO(MAX) tR tF tD tS VLO VHI ILO IHI tEN tDIS NOTES:
VCC = 3V, TA = +25C, unless otherwise specified. CONDITION MIN 2.7 RL = 1k, EV = 100lux EV = 0lux EN = VHI EV = 100lux EV = 10lux EV = 0lux at 95% of nominal output current, EV = 100lux RL = 5k, EV = 300lux RL = 1k, EV = 1000lux RL = 5k, EV = 300lux RL = 1k, EV = 1000lux RL = 5k, EV = 300lux RL = 1k, EV = 1000lux RL = 5k, EV = 300lux RL = 1k, EV = 1000lux 40 68 1 0.5 62.5 6.2 10 2.7 105 64 170 77 165 112 65 33 0.6 1.8 VEN = 0V VEN = 3V EV = 200lux EV = 200lux 0.01 2 140 2 85 TYP MAX 5.5 UNIT V A A A A A pA V s s s s s s s s V V A A s s
DESCRIPTION Power Supply Range Supply Current
Supply Current When Disabled Light Current Light Current Dark Current Maximum Output Compliance Voltage Rise Time (Note 2)
Fall Time (Note 2)
Delay Time for Rising Edge (Note 2)
Delay Time for Falling Edge (Note 2)
Maximum Voltage at EN Pin to Enable Minimum Voltage at EN Pin to Disable Input Current at EN Pin Input Current at EN Pin Enable Time Disable Time
2. Switching time measurement is based on Figures 1 and 2. 3. Fluorescent light is substituted by Green LED during production
2
FN7377.8 September 18, 2009
EL7900
PULSE DRIVE CH1 VCC 1V PULSE DRIVE VS = 3V TA = +27C 0.5V VOUT tR 80% 20% tF tD tS 1ms
EL7900 RL
VOUT
CH2
FIGURE 1. RISE/FALL TIME MEASUREMENT
FIGURE 2. RISE/FALL TIME MEASUREMENT WAVEFORMS
700
Typical Performance Curves
100 RELATIVE RESPONSE (%) 80 60 40 20 0 400 500 600 700 800 900 1k WAVE LENGTH (nm) EL7900 RELATIVE RESPONSE WITH IR GLASS FILTER EL7900 RELATIVE RESPONSE OUTPUT CURRENT (A) VCC = 3V 600 FLUORESCENT LIGHT 500 400 300 200 100 0 0 200 400 600 800 1000 ILLUMINATION (LX)
FIGURE 3. SPECTRAL RESPONSE
FIGURE 4. SENSITIVITY
1000
1.20 VDD = 3V 1.15 FLUORESCENT LIGHT OF 50lux
0
GAIN/GAIN (+25C)
VDD = 5V
1.10 1.05 1.00 0.95 0.90 0.85
IOUT (pA)
-1000
-2000
VDD = 3.3V
-3000
-4000 -45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 85 TEMPERATURE (C)
0.80 -60
-40
-20
0
20
40
60
80
100
TEMPERATURE (C)
FIGURE 5. DARK CURRENT vs TEMPERATURE
FIGURE 6. GAIN vs TEMPERATURE
3
FN7377.8 September 18, 2009
EL7900 Typical Performance Curves
0.6 OUTPUT COMPLIANCE VOLTAGE (VDD - VOUT) (V) 0.5 0.4 0.3 0.2 0.1 0 -200 VDD = 3V TA = +27C LUMINOSITY 30 ANGLE 40 50 60 70 80 0 200 400 600 800 1000 1200 90
RADIATION PATTERN
20 10 0 10 20 30 40 50 60 70 80 90 0.2 0.4 0.6 0.8 1.0 RELATIVE SENSITIVITY
OUTPUT CURRENT (A)
FIGURE 7. OUTPUT COMPLIANCE VOLTAGE vs CURRENT
FIGURE 8. RADIATION PATTERN
5 4 3 2 1 0 FLUORESCENT LIGHT SOURCE
IOUT (mA)
0
1k
2k
3k 4k 5k 6k 7k LUMINANCE (lux)
8k
9k
10k
FIGURE 9. IOUT vs LUMINANCE
Pin Descriptions
PIN 1 2 3 4 5 NAME VCC GND EN NC Output DESCRIPTION Supply, 2.7V to 5.5V Ground Enable No connect Current output pin
Block Diagram
VCC 1
3 ENABLE
5 OUTPUT
2 GND
4
FN7377.8 September 18, 2009
EL7900 Application Information
Product Description
The EL7900 is a light-to-current optical sensor combining photodiodes and current amplifiers on a single monolithic IC. The photodiodes are temperature-compensated and their spectrum resembles the human eye response. The output current is directly proportional to the intensity of light falling on the photodiodes. For 100lux of input fluorescent light, the EL7900 has an output current of 60A. The EL7900 is housed in an ultra-compact surface mount clear plastic package.
Resistor Output RLOAD Selection
The resistor output, RLOAD, determines the voltage transfer function of the device. The device converts light into current then RLOAD converts the output current to an output voltage. RLOAD can range from 10 to 10M depending on the input lux levels. The table below lists RLOAD values to maximize output swing for typical lux range levels. A careful balance of dynamic swing and fast response has to be considered when choosing RLOAD. For faster response, choose a smaller value RLOAD to shunt stray capacitances that may slow down response time. For maximum dynamic range or swing, choose a higher value RLOAD. Although finite, the output impedance of the device is considerably large. Hence, the light-to-current conversion deviation because of resistor loading is infinitesimal. The recommended maximum RLOAD is 10M. The output current must never exceed 6mA. When using load resistances less than 800, care must be taken when lux go as high as 10,000lux because the output current rises above 6mA before reaching the device's output compliance. The output compliance of the device is 300mV below the supply. The output current stops ramping when the output voltage reaches voltage compliance.
TABLE 1. VDD = 5V, MAXIMUM OUTPUT VOLTAGE = 4.7V ILLUMINATION RANGE (lux) 0 to 10 RLOAD (k) 783 39.2 15.7 7.8 0.78 CURRENT OUT (A) 0 to 6 0 to 120 0 to 300 0 to 600 0 to 6,000
Light-to-Current and Voltage Conversion
The EL7900 has a responsiveness that is directly proportional to the intensity of light intercepted by the photodiodes. Although the conversion rate varies depending on the light sources (fluorescent light, incandescent light or direct sunlight), in general for a fluorescent light, the light-tocurrent conversion is:
60A I OUT = ------------------ x L INPUT 100lux (EQ. 1)
Here, IOUT is the output current in A, and LINPUT is the input light in lux. For some applications, a load resistor is added between the output and the ground as shown in Figure 1. The output voltage can be expressed in Equation 2:
60A V OUT = I OUT x R LOAD = ------------------ x L INPUT x R LOAD 100lux
0 to 200 (EQ. 2) 0 to 500 0 to 1,000 0 to 10,000
Here, VOUT is the output voltage and RLOAD is the value of the load resistor added. The compliance of the EL7900's output circuit may result in premature saturation of the output current and voltage when an excessively large RLOAD is used. The output compliance voltage is 300mV below the supply voltage as listed in VO(MAX) of the Electrical Specifications table on page 2. In order to have the linear relationship between the input light and the output current and voltage, a proper resistor value (i.e., gain) should be picked for a specific input light range. The resistor value can be picked according to Equation 3:
( V SUP - 0.3V ) 100lux R LOAD = -------------------------------------- x ----------------------60A L RANGE
Application Examples
The following examples present from fully automatic to fully manual override implementations. These guidelines are applicable to a wide variety of potential light control applications. The EL7900 can be used to control the brightness input of CCFL inverters. Likewise, it can interface well with LED drivers. In each specific application, it is important to recognize the target environment and its ambient light conditions. The mechanical mounting of the sensor, light aperture hole size and use of a light pipe or bezel are critical in determining the response of the EL7900 for a given exposure of light. The example in Figure 10 shows a fully automatic dimming solution with no user interaction. Choose R1 and R2 values for any desired minimum brightness and slope. Choose C1 to adjust response time and to filter 50/60Hz room lighting. For example, suppose you wish to generate an output voltage from 0.25V to 1.25V to drive the input of an LED driver controller. The 0.25V represents the minimum LED
(EQ. 3)
Here, VSUP is the supply voltage, and LRANGE is the specific input light range for an application. For example, an indoor light ranges typically from 0lux to 1,000lux. A resistor value of 4.5k for 3V supply voltage can be used. For a small light range, a large resistor value should be used to achieve better sensitivity; for a large light range, a small resistor value should be used to prevent non-linear output current and voltage. 5
FN7377.8 September 18, 2009
EL7900
brightness and 1.25V represents the maximum. The first step would be to determine the ratio of R1 and R2:
3.0V R 1 = R 2 x --------------- - 1 = 11 x R 2 0.25V (EQ. 4)
Figure 12 shows how a fully manual override can be quickly added by using the EN pin.
3V TO 5V SUPPLY VOLTAGE 3V PWM CONTROL
3V TO 5V SUPPLY VOLTAGE
VDO 3V DC VOLTAGE ENABLE/ DISABLE CONTROL R1 110k
EL7900
EN OUT R2 10k
VDO R1 110k
TO INVERTER BRIGHTNESS INPUT OR CONTROLLER C1 25F
EL7900
EN OUT R2 10k TO INVERTER BRIGHTNESS INPUT OR LED DRIVER CONTROLLER C1 25F GND
GND
LED DRIVER
FIGURE 12. AUTOMATIC DIMMING SOLUTION WITH ADJUSTABLE BIAS CONTROL AND MANUAL OVERRIDE FIGURE 10. AUTOMATIC DIMMING SOLUTION
Short Circuit Current Limit
Next, the value of R2 can be calculated based on the maximum output current coming from the EL7900 under the application's maximum light exposure. Suppose the current has been determined to be about 125A. Thus, R2 can be calculated as shown in Equations 5 and 6:
1.25V R 2 = ----------------- = 10k 125A (EQ. 5)
The EL7900 does not limit the output short circuit current. If the output is directly shorted to the ground continuously, the output current could easily increase for a strong input light such that the device may be damaged. Maximum reliability is maintained if the output continuous current never exceeds 6mA by adding a load resistor at the output. This limit is set by the design of the internal metal interconnects.
and
R 1 = 11 x R 2 = 110k (EQ. 6)
Suggested PCB Footprint
Footprint pads should be a nominal 1-to-1 correspondence with package pads. The large, exposed central die-mounting paddle in the center of the package requires neither thermal nor electrical connections to PCB, and such connections should be avoided.
In Figure 11, user adjustable bias control has been added to allow control over the minimum and maximum output voltage. This allows the user to adjust the output brightness to personal preference over a limit range via the 3V PWM control.
3V TO 5V SUPPLY VOLTAGE 3V PWM CONTROL
Power Supply Bypassing and Printed Circuit Board Layout
The EL7900 is relatively insensitive to the printed circuit board layout due to its low speed operation. Nevertheless, good printed circuit board layout is necessary for optimum performance. Ground plane construction is highly recommended, lead length should be as short as possible and the power supply pins must be well bypassed to reduce the risk of oscillation. For normal single supply operation, where the GND pin is connected to ground, a 0.1F ceramic capacitor should be placed from VCC pin to GND pin. A 4.7F tantalum capacitor should then be connected in parallel, placed close to the device.
VDO R1 110k
EL7900
EN OUT R2 10k TO INVERTER BRIGHTNESS INPUT OR LED DRIVER CONTROLLER C1 25F
GND
FIGURE 11. AUTOMATIC DIMMING SOLUTION WITH ADJUSTABLE BIAS CONTROL
6
FN7377.8 September 18, 2009
EL7900
FIGURE 13. EL7900 SENSOR DIAGRAM
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com 7
FN7377.8 September 18, 2009
EL7900
Package Outline Drawing
L5.2x2.1
5 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE Rev 1, 05/08
6 PIN #1 INDEX AREA B 6 PIN 1 INDEX AREA 1 5 1
2.10
A
2.00
1.35 2 0.65
0.300.05 4
1.30 REF
(4X)
0.10 0.65
3
0.10 M C A B TOP VIEW 5X 0 . 35 0 . 05 BOTTOM VIEW
(0.65)
SEE DETAIL "X" 0.10 C 0 . 7 0 . 05 C BASE PLANE SIDE VIEW SEATING PLANE 0.08 C
(0.65) (1.35)
( 5X 0 . 30 )
( 5X 0 . 55 ) (1.95)
C
0 . 2 REF
5
0 . 00 MIN. 0 . 05 MAX. TYPICAL RECOMMENDED LAND PATTERN DETAIL "X"
NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994. 3. 4. Unless otherwise specified, tolerance : Decimal 0.05 Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip.
5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be either a mold or mark feature.
8
FN7377.8 September 18, 2009

▲Up To Search▲

Price & Availability of EL7900ILCZ-EVALZ

	To Download EL7900ILCZ-EVALZ Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .