LTR-S320-DB-L Phototransistor Datasheet - EIA Standard Package - 940nm Peak Sensitivity - Simplified Chinese Technical Documentation

1. Product Overview

LTR-S320-DB-L is a high-performance silicon NPN phototransistor specifically designed for infrared sensing applications. This component is optimized for near-infrared spectrum detection, with its peak sensitivity at 940nm, making it suitable for a wide range of remote control systems, object detection, and industrial automation tasks. Its primary function is to convert incident infrared light into a corresponding electrical current.

The device is housed in an EIA-standard package equipped with a black daylight-cut resin lens. This lens effectively filters out visible ambient light, significantly reducing noise and false triggering, thereby improving the signal-to-noise ratio under background illumination. The package design is compatible with high-volume automated assembly processes, including tape-and-reel feeding and infrared reflow soldering, meeting modern manufacturing requirements.

Kama "bidhaa ya kijani" inayokidhi viwango vya RoHS na isiyo na risasi, inakidhi viwango vya kisasa via mazingira. Mchanganyiko wa majibu ya wigo, muundo wa kifurushi, na upatanishi wa utengenezaji, hufanya iwe suluhisho thabiti na lenye matumizi mengi katika saketi za kugundua infrared zenye unyeti wa gharama na zinazotafuta utendaji.

2. Technical Parameters: An In-depth and Objective Interpretation

All electrical and optical characteristics are specified under the condition of an ambient temperature (T_A) of 25°C, providing a standardized benchmark for performance evaluation.

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. Operation of the device at or beyond these limits is not guaranteed, and circuit design should avoid such conditions.

• Power Dissipation (P_D):150 mW. This is the maximum allowable power that the device can dissipate as heat. Exceeding this limit risks thermal runaway and failure.
• Collector-Emitter Voltage (V_CEO):30 V. The maximum voltage that can be applied between the collector and emitter terminals when the base is open (phototransistor is in the dark state).
• Operating temperature range:-40°C to +85°C. The device is designed to operate normally within this ambient temperature range.
• Storage temperature range:-55°C to +100°C. The temperature range for storing the device in a non-operating state without degradation.
• Infrared soldering conditions:Kiwango cha juu cha joto 260°C, kwa muda wa sekunde 10 kwa upeo. Hii inafafanua mipaka ya mchakato wa uwekaji wa solder usio na risasi.

2.2 Electrical and Optical Characteristics

Vigezo hivi vinafafanua utendakazi wa kifaa chini ya masharti maalum ya majaribio.

• Reverse Breakdown Voltage (V_(BR)R):Minimum 33V, typical 170V (at I_R=100µA). This high value indicates a robust junction structure capable of withstanding significant reverse bias, which is beneficial for circuits with inductive loads or voltage spikes.
• Reverse dark current (I_D):Maximum 10 nA (at V_R=10V). This is the leakage current when no light is incident. Low dark current is crucial for achieving high sensitivity and low-noise operation, especially in low-light detection scenarios.
• Open-circuit voltage (V_OC):Typical value 390 mV (under 940nm light irradiation, irradiance E_e=0.5 mW/cm²). This parameter is relevant when the device is used in photovoltaic mode (without external bias).
• Short-circuit current (I_SC):Typical value 1.8 µA (test conditions same as V_OCsame, i.e., V_R=5V, λ=940nm, E_e=0.5 mW/cm²). This indicates the photocurrent generated when the output is short-circuited.
• Rise time (T_r) and fall time (T_f):both have a maximum value of 30 ns (V_R=10V, R_L=1kΩ). These switching speed specifications are crucial for applications requiring fast pulse detection or high-frequency modulation, such as data communication links.
• Total capacitance (C_T):Maximum 1 pF (V_R=5V, f=1MHz). Low junction capacitance is crucial for maintaining fast response times, as it limits the RC time constant of the circuit.
• Spectral bandwidth (λ_0.5):750 nm to 1100 nm. This defines the wavelength range over which the device responsivity is at least half of its peak value. It covers the common infrared region used by many infrared emitters, such as 850nm and 940nm LEDs.
• Peak sensitivity wavelength (λ_P):940 nm. Kifaa hiki kinalingana kwa wigo na LED ya infrared inayotoa mwanga wa 940 nm, na kuhakikisha ufanisi wa juu na nguvu ya ishara katika jozi kama hizi.

3. Uchambuzi wa Mviringo wa Utendaji

Maelezo ya udhibiti yanataja mikunjo ya kawaida ya sifa, ambayo inaonyesha wazi tabia ya kifaa chini ya hali tofauti. Ingawa michoro maalum haijarudiwa katika maandishi, uchambuzi wa maana yake ya kawaida umetolewa hapa chini.

3.1 IV (Current-Voltage) Characteristics

A set of curves, plotted under different levels of incident irradiance (E_C), depicting the collector current (I_CE) versus collector-emitter voltage (V_e). These curves typically show that for a fixed irradiance, I_Cincreases with V_CEuntil reaching the saturation region. Higher irradiance levels shift the curves upward, indicating greater photocurrent. The slope in the active region is related to the output conductance of the device.

3.2 Relative Sensitivity vs. Wavelength

Mkunjo huu unaonyesha kwa kielelezo msikivu wa wigo, ukifikia kilele kwenye 940nm na kupungua polepole kuelekea 750nm na 1100nm (λ_0.5). Hii ni muhimu kwa kuchagua kwa usahihi kiinua chini infrared kinacholingana na kigunduzi, na kutathmini athari za vyanzo vya mwanga vya mazingira vilivyo na wigo tofauti.

3.3 Utengamano wa Joto

The curve likely shows key parameters such as dark current (I_D) and photocurrent varying with ambient temperature. Dark current typically increases exponentially with temperature (approximately doubling every 10°C), which can be a significant noise source in high-temperature applications. Photocurrent may also have a slight negative temperature coefficient.

4. Taarifa za Mitambo na Ufungaji

4.1 Package Dimensions

The device conforms to the standard EIA package outline. All dimensions are provided in millimeters, with a standard tolerance of ±0.10 mm unless otherwise noted. The package employs a black daylight-cut resin lens covering the silicon chip.

4.2 Polarity Identification and Pin Definition

The phototransistor is a 2-pin device. The pin definition for this package is standard: the collector is typically connected to the case or the longer lead (if applicable), while the emitter is the other pin. The datasheet diagram provides clear identification. Correct polarity is crucial for proper circuit operation.

4.3 Recommended Pad Layout

Provides recommended pad patterns (package dimensions) for PCB design to ensure reliable solder joint formation during reflow soldering. Adhering to these dimensions helps prevent tombstoning, misalignment, or insufficient solder fillets.

5. Mwongozo wa Uchomaji na Usanikishaji

5.1 Mkunjo wa Joto wa Reflow Soldering

Provides detailed recommendations for infrared reflow soldering temperature profiles suitable for lead-free soldering processes. Key parameters include:

• Preheating:150°C to 200°C.
• Preheating Time:Maximum 120 seconds.
• Peak Temperature:Maximum 260°C.
• Time Above Liquidus (at Peak):Muda wa juu ni sekunde 10.
• Idadi ya juu ya kurudishwa tena: Two.

Mkunjo huu unategemea kiwango cha JEDEC ili kuhakikisha ukomo wa ufungaji. Wahandisi lazima waeleze mkunjo wao wa joto kulingana na muundo wao maalum wa PCB, vipengele na ufinye wa kuuza.

5.2 Manual Soldering

Ikiwa ni lazima kufanya uuzaji wa mkono, joto la ncha ya chuma cha kuuza halipaswi kuzidi 300°C, na wakati wa kuuza kwa kila pini unapaswa kuwa mdogo hadi sekunde 3. Inashauriwa kufanya mzunguko mmoja tu wa uuzaji wa mkono ili kuepuka mkazo wa joto.

5.3 Kusafisha

Ni lazima tumia tu vifaa vya kusafisha vilivyobainishwa. Inapendekezwa kutumia isopropanol (IPA) au ethanol. Kifaa kinapaswa kuzamishwa kwenye halijoto ya kawaida kwa chini ya dakika moja. Kemikali zisizobainishwa zinaweza kuharibu mfuko wa mfinyano.

5.4 Masharti ya Uhifadhi

Ufungashaji Uliofungwa (Mfuko wa Kuzuia Unyevu):Hifadhi chini ya masharti ya ≤30°C na ≤90% RH. Vipengele vina uhalali wa matumizi kwa muda wa mwaka mmoja kuanzia tarehe ya kufunga mfuko.

Ufungashaji Uliofunguliwa:Hifadhi chini ya hali ya ≤30°C na ≤60% RH. Vipengele vinapaswa kutiwa chuma kwa kuyeyusha ndani ya wiki moja (saa 168). Kwa uhifadhi wa muda mrefu zaidi nje ya mfuko wa asili, lazima ihifadhiwe kwenye chombo kilichotiwa muhuri chenye kivukizi au kivukizi cha nitrojeni. Vipengele vilivyohifadhiwa zaidi ya wiki moja vinapaswa kuokwa kwenye takriban 60°C kwa angalau saa 20 kabla ya kutiwa chuma, ili kuondoa unyevu uliovutwa na kuzuia tukio la "popcorn" wakati wa kuyeyusha tena.

6. Ufungaji na Taarifa za Kuagiza

6.1 Vipimo vya Ukanda na Reel

The device is supplied in 8mm carrier tape, wound on 7-inch (178mm) diameter reels, compatible with standard automated placement equipment.

• Quantity per reel: 3000.
• Cover tape:Empty component pockets are sealed with top cover tape.
• Missing component:According to reel specifications, a maximum of two consecutive missing components ("missing LEDs") is allowed per reel.
• Standard:Packaging complies with the ANSI/EIA 481-1-A-1994 specification.

7. Application Suggestions

7.1 Typical Application Scenarios

• Infrared Remote Control Receiver:Used for televisions, audio systems, and set-top boxes (paired with 940nm infrared LED).
• Object/Proximity Detection:Used in printers, copiers, vending machines, and industrial automation to sense paper, objects, or position.
• Smoke Detector:Used in designs based on optical cavities.
• Encoder:For speed or position sensing in motor control.
• Basic optocoupler:For low-speed, cost-sensitive optocoupler circuits.

7.2 Circuit Design Considerations

Njia ya Kuendesha:Phototransistor ni kifaa kinachotoa mkondo. Ili kupata utendakazi thabiti, hasa wakati vifaa vingi vinatumiwa sambamba, inashauriwa sana kuunganisha kizuizi cha mkondo (Mfano wa Sakiti A kwenye hati ya maelezo) kwa kila phototransistor.

Mfano wa Sakiti A (Inapendekezwa):Kila fototransista ina upinzani wake wa mfululizo unaounganishwa na voltage ya usambazaji. Hii inahakikisha kila kifaa kinafanya kazi katika sehemu iliyobainishwa ya sasa, kulipa fidia tofauti ndogo za sifa zake za sasa-voltage (I-V), na kuzuia kifaa kimoja "kukichukua" sehemu kubwa ya sasa.

Mfano wa Sakiti B (Haipendekezwi kwa Unganisho Sambamba):Fototransista nyingi zimeunganishwa sambamba moja kwa moja kwenye upinzani wa kushiriki. Kutokana na tofauti za asili katika mkunjo wa I-V wa vipengele binafsi, kifaa kimoja kinaweza kuchukua sasa zaidi kuliko vingine, na kusababisha usawa usio sawa wa mwangaza au unyeti katika matumizi ya kugundua.

Bias:This device is typically used in a common-emitter configuration with a pull-up resistor connected to the collector. The value of this load resistor (R_L) affects both the output voltage swing and the response speed (via the RC time constant formed with the device capacitance). A smaller R_Lprovides a faster response but results in a smaller output voltage change.

Uwezo wa Kukinga Kelele:Lenzi nyeusi ya kukata mwanga wa jua inatoa uwezo bora wa kuzuia mwanga unaoonekana. Hata hivyo, kwa mazingira yenye kelele nyingi (kwa mfano, yenye taa ya fluorescent au mwanga wa jua), inaweza kuhitajika uchujaji wa ziada wa umeme (kwa mfano, capacitor inayounganishwa sambamba na upinzani wa mzigo au algorithm za kufuta mshtuko kwa vifaa/ programu) ili kukinga usumbufu wa usanidi.

8. Ulinganishi wa Kiufundi na Tofauti

Ikilinganisha na photodiode rahisi, phototransistor hutoa faida ya ndani ya sasa (thamani ya β ya transistor), na hivyo kuzalisha sasa pato kubwa zaidi katika kiwango sawa cha mwanga kinachoanguka. Hii inafanya iwe rahisi kuunganisha moja kwa moja na mzunguko wa mantiki au microcontroller, bila haja ya hatua ya kuongeza nguvu ya baadaye, kurahisisha muundo na kupunguza idadi ya vipengele.

然而，这种增益的代价是响应速度较慢（光电晶体管通常为几十到几百纳秒，而光电二极管为纳秒级）以及可能更高的电容。对于非常高速的应用（例如，>1 MHz调制），带有外部跨阻放大器的光电二极管可能是更好的选择。

Sababu muhimu za utofautishaji za LTR-S320-DB-L katika kategoria ya phototransistor ni pamoja na: ufungaji wake wa kawaida wa EIA unaorahisisha utengenezaji, ulinganifu maalum wa wigo wa 940nm, lenzi iliyojumuishwa ya kuchuja mwanga wa mchana, na sifa zake zinazofaa kwa mchakato wa upitishaji tena usio na risasi.

9. Maswali Yanayoulizwa Mara kwa Mara (Kulingana na Vigezo vya Kiufundi)

9.1 What is the function of the "Daylight Cut-off" lens?

Lens ya mweusi ya resin imechanganywa na dutu maalum, hivyo haipitishi mwanga unaoonekana lakini inapitisi mawimbi ya infrared ya takriban 940nm. Hii inapunguza sana mkondo wa umeme unaotokana na mwanga wa mazingira ya ndani, jua, au vyanzo vingine vya mwanga unaoonekana, na hivyo kupunguza kiwango cha kusababisha hitilafu na kuongeza uaminifu wa kugundua mawimbi ya infrared.

9.2 Naweza kuitumia pamoja na LED ya infrared ya 850nm?

Ndiyo, lakini utendakazi utapungua. Mkunjo wa mwitikio wa wigo wa kifaa unaonyesha usikivu mkubwa kwenye 850nm (ndani ya upana wa mawimbi ya 750-1100nm), lakini sio kilele (940nm). Ishara ya pato itakuwa dhaifu zaidi ikilinganishwa na kutumia kitoa mwanga kinacholingana cha 940nm. Ili kupata utendakazi bora na umbali mkubwa zaidi, inashauriwa kuitumia pamoja na chanzo cha mwanga cha 940nm.

9.3 Ninawezaje kuhesabu thamani inayofaa ya upinzani uliosanidiwa mfululizo?

Thamani ya upinzani inategemea mkondo wa kazi unaohitajika na voltage ya usambazaji (V_CC). Under specific irradiance, the phototransistor behaves like a current source. Using Ohm's law: R = (V_CC- V_CE(sat)) / I_C. V_CE(sat)is the saturation voltage (typically a few hundred mV at moderate currents). I_Cis the desired collector current, which can be based on I_SCParameters and expected illumination levels are estimated. Starting from a typical I_SCvalue (1.8 µA at 0.5 mW/cm²) and scaling according to the irradiance of your application. Select R to set the operating point in the desired region of the IV curve.

9.4 Why is baking required if components are stored outside the moisture barrier bag?

Plastic packages absorb moisture from the atmosphere. During the high-temperature reflow soldering process, this trapped moisture rapidly vaporizes, creating high internal pressure. This can lead to package delamination from the die ("popcorn" effect) or internal cracks, resulting in immediate or latent failures. Baking drives out this absorbed moisture, allowing the components to be safely reflow soldered.

10. Working Principle

Phototransistor kimsingi ni transistor ya makutano ya bipolar (BJT) ambayo sasa ya msingi inazalishwa na mwanga, na sio muunganisho wa umeme. Photons za mwanga zinazoingia zenye nguvu zaidi ya pengo la bendi ya silicon huzalisha jozi za elektroni na shimo katika eneo la makutano ya msingi-kolekta. Mabebaji haya hukamatwa na uga wa umeme wa ndani, na kuzalisha sasa ya mwanga ambayo hufanya kama sasa ya msingi (I_B) ya mwanga. Kisha, sasa hii ya msingi inayozalishwa na mwanga huongezeka kwa faida ya sasa ya transistor (h_FEor β), thereby generating a much larger collector current (I_C= β * I_B). The output is taken from the collector terminal, with the emitter grounded. The absence of a physical base pin is a common feature, although some phototransistors include a base connection for bias control or speed optimization.

11. Mwelekeo wa Maendeleo

Uwanja wa Ugunduzi wa Umeme na Mwanga unaendelea kukua. Mienendo inayohusiana na vifaa kama vile LTR-S320-DB-L ni pamoja na:

• Kupunguzwa kwa Ukubwa:Kukuza ukubwa wa ufungashaji mdogo zaidi (mfano, ufungashaji wa kiwango cha chip) kwa transistor za mwanga, ili kufikia vifaa vya elektroniki vilivyo na msongamano mkubwa.
• Kuimarisha Kiwango cha Ujumuishaji:Kujumuisha vigunduzi vya mwanga na kikuza, kichujio na mantiki ya dijiti kwenye chip moja, kuunda "sensabure zenye akili" zenye pato la dijiti (I2C, SPI), kupunguza idadi ya vipengele vya nje na kurahisisha muundo wa mfumo.
• Kuongeza kasi:Kuchunguza muundo na nyenzo za kupunguza muda wa kuvuka wa wabebaji na capacitance, ili kuongeza upana wa ukanda wa fototransistor kwa matumizi ya mawasiliano ya data.
• Upekee wa urefu wa wimbi:Kukua vichunguzi vyenye mwitikio wa wigo ulio nyembamba na uliosawazishwa kwa usahihi zaidi, ili kuboresha uhitimaji katika mazingira yenye vyanzo vingi vya infrared, au kufikia njia mpya za kuhisi.
• Makini kwa uaminifu na majaribio:Teknolojia ya optoelectroniki inapopenya katika matumizi ya magari, matibabu na usalama wa viwanda, msisitizo unaozidi kuwa juu wa viwango vya usajili madhubuti, masafa ya halijoto ya kazi yaliyopanuliwa, na uchambuzi wa aina za kushindwa.

Ingawa phototransistor tofauti bado ni muhimu katika matumizi mengi kwa sababu ya unyenyekevu na ufanisi wa gharama, mwelekeo huu unaonyesha kwamba baadaye kutakuwa na suluhisho ngumu zaidi na zilizolengwa kwa matumizi maalum.