AMS TSL238 Datasheet
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TSL238
High-Sensitivity Light-to-Frequency
Converter
General Description
The TSL238 light-to-frequency converter combines a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS integrated circuit. Output is a square wave
(50% duty cycle) with frequency directly proportional to light intensity (irradiance) on the photodiode. The digital output allows direct interface to a microcontroller or other logic circuitry. Output enable (OE) places the output in a high-impedance state for multiple-unit sharing of a microcontroller input line. The device has been temperature compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm and responds over the light range of 320 nm to
1050 nm. The TSL238 is characterized for operation over the temperature range of -40°C to 85°C and is supplied in an 8-lead plastic small outline package. When supplied in the lead (Pb) free package, the device is RoHS compliant.
For automotive and other extended temperature applications, please contact
ams
for information.
and
appear at end of datasheet.
Figure 1:
Added Value of Using TSL238
Benefits
•
Detects Light Intensity at a High Resolution
•
Provides Low Light Level Operation
•
Reduces Board Space Requirements while
Simplifying Designs
Key Benefits & Features
The benefits and features of TSL238, High-Sensitivity
Light-to-Frequency Converter are listed below:
Features
•
850000:1 Input Dynamic Range
•
Low Dark Frequency < 2 Hz at 25°C
•
5mm x 6.2mm SOIC (D) Package
ams Datasheet
[v1-00] 2016-Aug-30
•
High-Resolution Conversion of Light Intensity to
Frequency with No External Components
•
High Irradiance Responsivity: 2.3kHz/(mW/cm
λ p
= 524 nm
2
)
•
Single-Supply Operation: 2.7 V to 5.5 V
•
Stable 200 ppm/°C Temperature Coefficient
•
Interfaces Directly to a Microcontroller
•
Lead (Pb) Free Package, RoHS Compliant
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General Description
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
TSL238 Block Diagram
Light Photodiode
Current-to-Frequency
Converter
Output
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TSL238 −
Pin Assignment
Pin Assignment
Figure 3:
Package D 8-Lead SOIC (Top View)
NC 1
NC 2
NC 3
NC 4
8 OUT
7 V
DD
6 GND
5 OE
Figure 4:
Terminal Functions
Terminal
Name D Pkg No.
GND
NC
6
1, 2, 3
Type
NC 4
Description
Power supply ground. All voltages are referenced to GND.
No connection.
Substrate. Pin 4 is resistively connected to the substrate of the die, which is at the same potential as pin 6. Pin 4 must either be connected to pin 6 or left unconnected. Pin 4 cannot be used for a ground connection by itself.
O
(active low).
V
DD
ams Datasheet
[v1-00] 2016-Aug-30
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Absolute Maximum R atings
Absolute Maximum Ratings
Stresses beyond those listed under
may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating Conditions
is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability.
Figure 5:
Absolute Maximum Ratings over Operating Free-Air Temperature Range (unless otherwise noted)
Symbol
V
DD
V
I
I
O
T
A
T strg
Parameter
Supply voltage
Input voltage range
Output current
Short circuit of output to ground duration
Operating free-air temperature range
Storage temperature range
Solder conditions in accordance with JEDEC
J-STD-020A, maximum temperature
Min
-0.3
-40
-40
Max
6
V
DD
+0.3
±5
5
85
85
260
Units
V
V mA s
°C
°C
°C
Note(s):
1. All voltages are with respect to GND.
2. Long-term storage or operation above 70°C could cause package yellowing that will lower the sensitivity to wavelengths < 500nm.
3. The device may be hand soldered provided that heat is applied only to the solder pad and no contact is made between the tip of the solder iron and the device lead. The maximum time heat should be applied to the device is 5 seconds.
Figure 6:
Recommended Operating Conditions
Symbol
V
DD
V
IH
V
IL
T
A
Parameter
Supply voltage
High-level input voltage
Low-level input voltage
Operating free-air temperature
Min
2.7
0.8
×
V
DD
0
-40
Nom
5
Max Units
5.5
V
DD
0.5
70
V
°C
V
V
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Electrical Characteristics
Electrical Characteristics
Figure 7:
Electrical Characteristics at V
DD
= 5 V, T
A
(unless otherwise noted)
Symbol
V
OH
V
OL
I
IH
I
IL
I
DD
Parameter
High-level output voltage
Low-level output voltage
High-level input current
Low-level input current
Supply current k
SVS
Full-scale frequency
Temperature coefficient of responsivity
Supply-voltage sensitivity
Test Conditions
I
OH
= -1 mA
I
OL
= 1 mA
E e
= 21.2
μ
W/cm
2
T
A
= 50°C
Wavelength < 600nm, f
O
= 50 kHz
V
DD
= 5 V ± 10%
Min Typ Max
4 4.5
0.25
-10
-10
0.4
10
10
2 3
500 1000
Unit
V
V
μ
A
μ
A mA kHz
±200
±0.5
ppm/°C
%/V
Note(s):
1. The input irradiance is supplied with green LED light source with peak wavelength = 524 nm.
2. Full-scale frequency is the maximum frequency of the device without saturation. Higher irradiance will not result in any additional increase of output frequency. The output frequency will remain at approximately the saturation frequency to a minimum of 1000
μ
W/sqcm 524-nm irradiance. During production testing, devices are not tested at this very high irradiance level.
3. Measured at wafer probe using 50°C hot chuck.
ams Datasheet
[v1-00] 2016-Aug-30
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Electrical Characteristics
Figure 8:
Operating Characteristics at V
DD
= 5 V, T
A
= 25°C,
λ
p
= 524 nm (unless otherwise noted)
Symbol
f
O
Parameter
Output frequency f
D
R e
λ p
Dark frequency
Irradiance responsivity
Peak response wavelength
Step response to full-scale step input
Time from OE low to output enabled
Test Conditions
E e
= 21.2
μ
W/cm
2
E e
= 0
μ
W/cm
2
E e
= 0
μ
W/cm
2
, T
A
f
O
= 0 kHz to 10 kHz
Min
40
0
0
Typ
50
2.3
700
Max
60
± 1%
1 pulse of new frequency plus 1
μ s
1 period of output frequency
1.2
6
Unit
kHz
Hz
Hz kHz/(
μ
W/ cm
2
) nm
%F.S.
Note(s):
1. Measured at wafer probe using 50°C hot chuck.
2. Nonlinearity is defined as the deviation from a straight line between zero and maximum of stated range, expressed as a percent of stated range.
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Typical Operating Characteristics
Typical Operating
Characteristics
Figure 9:
Output Frequency vs Irradiance
1000
100
V
DD
= 5 V
λ
p
= 524 nm
T
A
= 25
°
C
10
1
0.1
0.01
0.001
0.001
0.01
0.1
1 10
E e
− Irradiance −
μ
W/cm
2
10 0 1 k
Figure 10:
Photodiode Spectral Responsivity
1
0.8
0.6
0.4
0.2
0
300 400 500 600 700 800 900
λ
− Wavelength − nm
1000 1100 ams Datasheet
[v1-00] 2016-Aug-30
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Typical Operating Characteristics
Figure 11:
Supply Current vs. Free-Air Temperature
2.0
1.6
1.2
0.8
0.4
0
−25 0 25 50
T
A
− Free-Air Temperature −
°
C
Figure 12:
Output Frequency vs. Free-Air Temperature
75
1.200
1.100
1.000
0.900
0.800
0.700
0.600
0.500
−25
T
A
0 25 50
− Free-Air Temperature −
°
C
75 ams Datasheet
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Typical Operating Characteristics
Figure 13:
Normalized Output Frequency vs. Angular Displacement
1
0.8
0.6
0.4
0.2
0
−90
Angular Displacement is
Equal for Both Aspects
−60 −30 0 30
− Angular Displacement −
°
60
90
Figure 14:
Dark Frequency vs. Free-Air Temperature
7.5
6.0
4.5
3.0
1.5
0.0
−1.5
−3.0
−4.5
−6.0
−7.5
−25
NOTE A
−5 15 35 55
T
A
− Free-Air Temperature −
°
C
75
Note(s):
Internal offsets that result in dark frequency can be both positive and negative. The dashed line represents the case of negative offset in which an equivalent amount of light signal is required to obtain a non-zero output frequency.
ams Datasheet
[v1-00] 2016-Aug-30
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Typical Operating Characteristics
Figure 15:
Photodiode Responsivity Temperature Coefficient vs.
Wavelength Of Incident Light
11k
10k
9k
8k
7k
6k
5k
4k
3k
2k
1k
0
600 650 700 750 800 850 900 950 1000
λ
− Wavelength of Incident Light − nm
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TSL238 −
Application Information
Application Information
Power-supply lines must be decoupled by a 0.01-
μ
F to 0.1-
μ
F capacitor with short leads placed close to the TSL238
(
Figure 16 ). A low-noise power supply is required to minimize
jitter on output pulse.
Figure 16:
Typical TSL238 Interface to a Microcontroller
V
DD
0.1
μ
F
V
DD
TSL238
OUT
GND
Timer / Port
MCU ams Datasheet
[v1-00] 2016-Aug-30
Device Operational Details
The frequency at the output pin (OUT ) is given by:
(EQ1)
f
O
= f
D
+ R e
⋅
E e where: f
O f
D
R e
is the output frequency
is the output frequency for dark condition (E e
= 0)
is the device responsivity for a given wavelength of light given in kHz/(
μ
W/cm
2
)
is the incident irradiance in
μ
W/cm
2
E e f
D
is a constant error term in the output frequency calculation resulting from leakage currents, and is independent of light intensity. The TSL238 die is trimmed to minimize the magnitude of this dark frequency component so that it can be neglected in the transfer function calculation. In many applications, measurement of the actual dark frequency may be impractical due to measurement times ranging from several seconds to several minutes, and the fact that some devices may never transition (zero dark frequency).
Output Interface
The output of the device is designed to drive a CMOS logic input over short distances. If lines greater than 12 inches in length are used on the output, a buffer or line driver is recommended.
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Application Information
Measuring The Frequency
The choice of interface and measurement technique depends on the desired resolution and data-acquisition rate. For maximum data-acquisition rate, period-measurement techniques are used.
Period measurement requires the use of a fast reference clock with available resolution directly related to the reference-clock rate. The technique is employed to measure rapidly varying light levels or to make a fast measurement of a constant light source.
Maximum resolution and accuracy may be obtained using frequency-measurement, pulse-accumulation, or integration techniques. Frequency measurements provide the added benefit of averaging out random- or high-frequency variations
(jitter) resulting from noise in the light signal. Resolution is limited mainly by available counter registers and allowable measurement time. Frequency measurement is well suited for slowly varying or constant light levels and for reading average light levels over short periods of time. Integration, the accumulation of pulses over a very long period of time, can be used to measure exposure — the amount of light present in an area over a given time period.
Output enable (OE) places the output in a high-impedance state for multiple-unit sharing of a microcontroller input line. When the OE line goes low, the device resynchronizes the output to an integration cycle. The rising edge of the output signal (OUT ) will occur exactly one period of the output frequency after OE goes low.
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ams Datasheet
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TSL238 −
Mechanical Data
Mechanical Data
This SOIC package consists of an integrated circuit mounted on a lead frame and encapsulated with an electrically nonconductive clear plastic compound having an index of refraction of 1.55.
Figure 17:
Package D — Plastic Small Outline IC Packaging Configuration
PACKAGE D
TOP VIEW
PLASTIC SMALL-OUTLINE
BOTTOM VIEW
PIN 1
NOTE B
6 1.27
8
0.510
0.330
PIN 1
SIDE VIEW
1.75
1.35
0.50
0.25
2.8 TYP
CLEAR WINDOW
45
END VIEW
0.88 TYP TOP OF
SENSOR DIE
A
5.00
4.80
5.3
MAX
4.00
3.80
6.20
5.80
DETAIL A
Pb
Lead Free
RoHS
Green
1.27
0.41
0.25
0.19
0.25
0.10
Note(s):
1. All linear dimensions are in millimeters.
2. The center of the 0.84-mm by 0.84-mm photo-active area is located in the center of the package ± 0.25 mm.
3. Pin 4 is resistively coupled to the substrate of the die, which is at the same potential as Pin 6. Pin 4 must either be connected to Pin
6 or left unconnected. Pin 4 cannot be used as the sole ground connection.
4. Leads are plated with Pd (min 0.1
μ inch) + Ni (min 10
μ
inch) + Au (min 0.1
μ
inch).
5. This drawing is subject to change without notice.
ams Datasheet
[v1-00] 2016-Aug-30
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Mechanical Data
Figure 18:
Package D Carrier Tape
SIDE VIEW
K o
2.11 0.10 [0.083 0.004]
0.292 0.013
[0.0115 0.0005]
TOP VIEW
1.50
8 0.1
[0.315
0.004]
A
DETAIL A
A
A o
6.45 0.10
[0.254 0.004]
B
4 0.1
[0.157
0.004]
2 0.05
[0.079
0.002]
B
1.75 0.10
[0.069 0.004]
END VIEW
5.50 0.05
[0.217 0.002]
12 + 0.3 − 0.1
[0.472 + 0.12 − 0.004]
DETAIL B
B o
5.13 0.10
[0.202 0.004]
Note(s):
1. All linear dimensions are in millimeters [inches].
2. The dimensions on this drawing are for illustrative purposes only. Dimensions of an actual carrier may vary slightly.
3. Symbols on drawing Ao, Bo, and Ko are defined in ANSI EIA Standard 481-B 2001.
4. Each reel is 178 millimeters in diameter and contains 1000 parts.
5.
ams
packaging tape and reel conform to the requirements of EIA Standard 481-B.
6. This drawing is subject to change without notice.
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TSL238 −
Manufacturing Information
Manufacturing Information
Figure 19:
TSL238 Solder Reflow Profile
Parameter
Average temperature gradient in preheating
Soak time
Time above 217°C
Time above 230°C
Time above T peak
−10°C
Peak temperature in reflow
Temperature gradient in cooling
The Plastic Small Outline IC package (D) has been tested and has demonstrated an ability to be reflow soldered to a PCB substrate.
The solder reflow profile describes the expected maximum heat exposure of components during the solder reflow process of product on a PCB. Temperature is measured on top of component. The component should be limited to a maximum of three passes through this solder reflow profile.
Reference
t soak t
1 t
2 t
3
T peak
TSL238
2.5°C/s
2 to 3 minutes
Max 60 s
Max 50 s
Max 10 s
260°C (−0°C/5°C)
Max −5°C/s
Figure 20:
Solder Reflow Profile Graph
Not to scale — for reference only
T peak
T
3
T
2
T
1
Time (s) t soak t
3 t
2 t
1 ams Datasheet
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Moisture Sensitivity
Optical characteristics of the device can be adversely affected during the soldering process by the release and vaporization of moisture that has been previously absorbed into the package molding compound. To prevent these adverse conditions, all devices shipped in carrier tape have been pre-baked and shipped in a sealed moisture-barrier bag. No further action is necessary if these devices are processed through solder reflow within 24 hours of the seal being broken on the moisture-barrier bag.
However, for all devices shipped in tubes or if the seal on the moisture barrier bag has been broken for 24 hours or longer, it is recommended that the following procedures be used to ensure the package molding compound contains the smallest amount of absorbed moisture possible.
For Devices Shipped In Tubes:
1.
Remove devices from tubes
2.
Bake devices for 4 hours, at 90°C
3.
After cooling, load devices back into tubes
4.
Perform solder reflow within 24 hours after bake
Bake only a quantity of devices that can be processed through solder reflow in 24 hours. Devices can be re-baked for 4 hours, at 90°C for a cumulative total of 12 hours (3 bakes for 4 hours at 90°C).
For Devices Shipped In Carrier Tape:
1.
Bake devices for 4 hours, at 90°C in the tape
2.
Perform solder reflow within 24 hours after bake
Bake only a quantity of devices that can be processed through solder reflow in 24 hours. Devices can be re-baked for 4 hours in tape, at 90°C for a cumulative total of 12 hours (3 bakes for 4 hours at 90°C).
ams Datasheet
[v1-00] 2016-Aug-30
TSL238 −
Ordering & Contact Information
Ordering & Contact Information
Figure 21:
Ordering Information
Ordering
Code
TSL238D-TR
Device
TSL238
T
A
-25°C to 70°C
Package − Leads
8-lead Plastic Small Outline IC
Package
Designator
D
Buy our products or get free samples online at: www.ams.com/ICdirect
Technical Support is available at: www.ams.com/Technical-Support
Provide feedback about this document at: www.ams.com/Document-Feedback
For further information and requests, e-mail us at: [email protected]
For sales offices, distributors and representatives, please visit: www.ams.com/contact
Headquarters
ams AG
Tobelbader Strasse 30
8141 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
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TSL238 −
RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS:
The term RoHS compliant means that ams AG products fully comply with current RoHS directives. Our semiconductor products do not contain any chemicals for all 6 substance categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, RoHS compliant products are suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br):
ams Green defines that in addition to RoHS compliance, our products are free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous material).
Important Information:
The information provided in this statement represents ams AG knowledge and belief as of the date that it is provided. ams AG bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. ams AG has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ams AG and ams AG suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
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TSL238 −
Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
Austria-Europe. Trademarks Registered. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. This product is provided by ams AG “AS IS” and any express or implied warranties, including, but not limited to the implied warranties of merchantability and fitness for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or other services.
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TSL238 −
Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Product Status
Pre-Development
Pre-Production
Production
Discontinued
Definition
Information in this datasheet is based on product ideas in the planning phase of development. All specifications are design goals without any warranty and are subject to change without notice
Information in this datasheet is based on products in the design, validation or qualification phase of development.
The performance and parameters shown in this document are preliminary without any warranty and are subject to change without notice
Information in this datasheet is based on products in ramp-up to full production or full production which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade
Information in this datasheet is based on products which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and should not be used for new designs
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ams Datasheet
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TSL238 −
Revision Information
Revision Information
Changes from 073J (2008-Sep) to current revision 1-00 (2016-Aug-30)
Content of TAOS datasheet was updated to latest
ams
design
Added Figure 1
Note(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Page
ams Datasheet
[v1-00] 2016-Aug-30
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Content Guide
TSL238 −
Content Guide
1 General Description
1 Key Benefits & Features
2 Functional Block Diagram
3 Pin Assignments
4 Absolute Maximum Ratings
5 Electrical Characteristics
7 Typical Operating Characteristics
11 Application Information
11 Device Operational Details
11 Output Interface
12 Measuring The Frequency
13 Mechanical Data
15 Manufacturing Information
16 Moisture Sensitivity
16 For Devices Shipped In Tubes
16 For Devices Shipped In Carrier Tape
17 Ordering & Contact Information
18 RoHS Compliant & ams Green Statement
19 Copyrights & Disclaimer
20 Document Status
21 Revision Information
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