LTH-301-07P5 Slot Type Photoelectric Switch Specification Sheet - Technical Documentation

1. Product Overview

LTH-301-07P5 is a slot-type photoelectric switch, a type of photoelectric component specifically designed for non-contact switching applications. It integrates an infrared light-emitting diode (LED) and a phototransistor within a compact slotted housing. Its basic operating principle is: an external object interrupts the infrared beam between the emitter and the detector, causing a corresponding change in the output signal of the phototransistor. This design provides a reliable and precise method for the non-contact detection of an object's presence, absence, or position.

The core advantage of this device lies in its non-contact nature, which eliminates mechanical wear, thereby achieving high reliability and long service life. It features fast switching speed, making it suitable for applications requiring rapid detection. The component is designed for direct printed circuit board (PCB) mounting or for use with a dual in-line package (DIP) socket, offering flexibility in system design and assembly.

Typical target markets and applications include, but are not limited to, office automation equipment such as fax machines, copiers, printers, and scanners. It is also widely used in various industrial automation, consumer electronics, and instrumentation systems that require precise object detection.

2. In-depth and Objective Interpretation of Technical Parameters

2.1 Absolute Maximum Ratings

Absolute Maximum Ratings define the stress limits that may cause permanent damage to the device. These ratings are specified at an ambient temperature (TA) of 25°C and should not be exceeded, even momentarily, under normal operating conditions.

Input LED:The continuous forward current is limited to 50 mA, with a peak forward current of 1 A allowed under pulse conditions (300 pulses per second, 10 μs pulse width). The maximum power dissipation of the LED is 80 mW. The reverse withstand voltage capability is 5 V, which is a key parameter for protecting the LED from accidental reverse bias.

Output Phototransistor:Collector-Emitter Voltage (V_CE) The rating is 30 V, while the emitter-collector voltage (V_EC) is 5 V. The maximum collector current is 20 mA, and the power dissipation limit is 100 mW. Adhering to these limits is crucial for ensuring the long life and stable operation of the phototransistor.

Environmental Limits:The operating temperature range of the device is rated from -25°C to +85°C. The storage temperature range is wider, from -40°C to +100°C. The pin soldering temperature is specified as 260°C for 5 seconds measured 1.6mm from the case, which is key information for the assembly process.

2.2 Electrical and Optical Characteristics

These characteristics define the expected performance of the device under normal operating conditions at 25°C. They provide key parameters for circuit design.

Input LED Characteristics:When the forward current (I_F) is 20 mA, the typical forward voltage (V_F) is 1.2 V, with a maximum of 1.6 V. This parameter is crucial for designing the current-limiting resistor in an LED drive circuit. At a reverse voltage (V_R) of 5 V, the maximum reverse current (I_R) is 100 μA, indicating the leakage current of the LED in the off state.

Output phototransistor characteristics:At V_CEOWhen =10V, the collector-emitter dark current (I_CE) is at most 100 nA, representing the output leakage current when the LED is off (no light). The breakdown voltage (BV_CEOand BV_ECO) Confirmed the maximum ratings.

Coupler (System) Characteristics:These parameters describe the combined performance of the LED and the phototransistor. When the LED is driven at I_{=20mA and V}=5V, ensuring the on-state collector current (I_F) is at least 0.6 mA. This is the key output signal level when the slot is not blocked. Under the same conditions, when I_CE=0.2mA, the collector-emitter saturation voltage (V_{) is a maximum of 0.4 V, indicating its good "on" state characteristics. Response time, typical rise time (T}) is 3 μs, fall time (T_C) is 4 μs (under specific test conditions), defining the device's switching speed capability._r3. Mechanical and Packaging Information_f3.1 External Dimensions

LTH-301-07P5 uses a standard through-hole package. Detailed mechanical drawings are provided in the specification sheet. All dimensions are specified in millimeters. The standard tolerance for unspecified dimensions is ±0.25 mm. Key dimensions include the overall length, width, and height of the housing, the slot width and slot depth (which define the gap that interrupts object passage), as well as the pin pitch and diameter. This component is designed for wave soldering or hand soldering processes.

Polarity Identification:

This device has a specific pin arrangement. Typically, the longer pin or a specific marking on the housing indicates the anode of the LED. The dimension drawing must be consulted for exact pin identification (e.g., Pin 1 is usually the LED anode, Pin 2 is the LED cathode, Pin 3 is the phototransistor emitter, and Pin 4 is the collector) to ensure correct orientation during PCB assembly. Incorrect polarity will cause the device to malfunction.

4. Welding and Assembly GuideProper handling during the soldering process is crucial to prevent damage to the plastic housing and internal semiconductor chip.

General Precautions:

The case must not be immersed in solder. Do not apply any external stress to the lead frame while the product is at a high temperature during the soldering process, as this may cause internal cracks or misalignment.

Manual/Pin Soldering:For manual soldering, the recommended maximum soldering iron temperature is 350°C. The soldering time per lead should not exceed 3 seconds, and each lead should be soldered only once. The solder joint should be no less than 2 mm from the component body base to prevent thermal damage.

Wave soldering:For automatic wave soldering, a specific temperature profile is recommended. The preheat temperature should not exceed 100°C, with a maximum preheat time of 60 seconds. The solder wave temperature is a maximum of 260°C, with a contact time not exceeding 5 seconds. The immersion position must be no less than 2 mm from the body base. Following this profile prevents thermal shock and ensures reliable solder joints without compromising the integrity of the plastic package.

5. Yanayin Ajiya da Abubuwan LuraTo maintain solderability and prevent performance degradation, specific storage conditions must be observed.

The ideal storage environment is a temperature below 30°C and a relative humidity below 70%. Components should be assembled within 3 months of the delivery date. If the parts are still in their original moisture-proof packaging, to extend storage life, they should be stored in a sealed container with appropriate desiccant or in a nitrogen-purged desiccator. However, under these controlled conditions, the storage time should not exceed one year.

一旦打开原始密封包装，元件必须在3个月内使用，并应保存在<25°C且相对湿度<60%的受控环境中。必须避免环境温度的快速变化，尤其是在高湿度环境中，以防止冷凝，冷凝会导致元件引脚氧化。如果存储条件不符合规定标准，引脚的可焊性可能会受到影响。在这种情况下，在生产使用前必须进行可焊性评估和潜在的元件重新筛选。

6. Shawarar Aikace-aikace

6.1 Typical Application Scenarios

LTH-301-07P5 is widely used and can be applied in numerous applications:

Paper detection in printers/copiers/scanners:

Detects paper presence, paper jams, or the end of a paper roll.

• Induksi posisi:Deteksi posisi asal atau batas perjalanan mekanisme bergerak (seperti kereta printer, lengan robot).
• Pengkodean rotasi:Used in conjunction with slotted wheels to measure the speed or position of a rotating shaft.
• Object counting:Counting items on a conveyor belt as they pass through a slot.
• Security System:As part of a beam interruption sensor, used for intrusion detection.
• 6.2 Design ConsiderationsWhen designing a circuit using this slot-type photoelectric switch, several factors must be considered:

LED drive current:

The recommended operating current is 20 mA. It must be determined based on the power supply voltage (V

• ) and the LED forward voltage (V) Use Ohm's law to calculate the series resistance: R = (V_CC- V_F) / I_CC. Using typical V_F=1.2V and 5V power supply, the resistor is approximately (5V - 1.2V) / 0.02A = 190 ohms. A standard 200 ohm resistor is suitable._FPhototransistor biasing:_FThe phototransistor output can be used in a common-emitter configuration (emitter grounded, collector through load resistor R
• Pull up to V) or used as a switch. R_CCvalue affects output voltage swing and switching speed. A smaller R_Lprovides faster response but smaller output voltage change. The datasheet test condition uses R_L=100Ω._LSignal conditioning:_LThe output is an analog current that varies with light intensity. For digital switching applications, it may be necessary to add a comparator or Schmitt trigger circuit after the load resistor to provide a clean digital signal, especially when the interrupting object does not completely block the light beam.
• Ambient light immunity:Since this device uses infrared light, it has a certain immunity to visible ambient light. However, strong infrared light sources (such as sunlight, incandescent bulbs) can affect performance. Using a modulated LED drive signal and synchronous detection can significantly enhance immunity to ambient light interference.
• Mechanical Alignment:The interrupting object must reliably pass through the slot and completely interrupt the beam to ensure consistent operation. The slot dimensions and the object's size and path must be carefully considered.
• 7. Technical Comparison and DifferentiationSlot-type photoelectric switches like the LTH-301-07P5 compete with other sensing technologies, such as mechanical micro switches, Hall effect sensors, and reflective optical sensors.

Compared to mechanical switches:

The main advantage is complete absence of physical contact, resulting in nearly infinite mechanical lifespan, no contact bounce, silent operation, and higher reliability in dirty or dusty environments. The drawback may be slightly higher cost and the need for electronic drive circuitry.

Compared with reflective optical sensors:Slot-type photoelectric switches provide higher positional accuracy and consistency because the emitter and detector are precisely aligned in a fixed geometric structure. They are less susceptible to changes in the reflectivity of the target object. Reflective sensors are more suitable for detecting objects at long distances or in situations where physical slots cannot be installed.

Compared with Hall effect sensors:Hall sensors detect magnetic fields, not light interruption. They are used to sense the position of magnets. The choice depends entirely on the application: detecting any opaque object (slot-type photoelectric switch) versus detecting a magnetic field (Hall sensor).

The specific differentiation of the LTH-301-07P5 lies in its balanced electrical characteristics (forward voltage, output current, speed), a robust mechanical package suitable for wave soldering, and its clearly specified storage and handling requirements, making it a reliable choice for volume manufacturing.8. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the "Peak Forward Current" rating for an LED?

A: This rating (1A at 300pps, 10μs) allows the LED to be pulse-driven at a current significantly higher than its continuous rating (50mA) for short durations. This can be used to achieve brighter light pulses, thereby improving the signal-to-noise ratio or allowing for a lower duty cycle, which reduces average power consumption and heat generation.

Q: I
It is specified as a minimum of 0.6mA. What does this mean for my circuit design?

A: This is a guaranteed lower limit. Under standard test conditions (I_{=20mA, V}=5V), when the slot is unobstructed, the phototransistor will sink at least 0.6mA of current. The actual current in your application may be higher. You must design your load resistor (R
) and any subsequent logic gates, to identify the voltage level corresponding to this minimum current. For example, when R_F=1kΩ and the light beam is not blocked, the output voltage will drop to at most V_CE= 5V - (0.6mA * 1kΩ) = 4.4V.Q: Why are the storage conditions so strict, especially after opening the packaging bag?A: Component pins exposed to humid air are prone to oxidation. Oxidized pins have poor solderability, which can lead to weak solder joints or failure to form a solder joint ("dewetting"). Moisture barrier packaging and strict storage rules are industry standard practices (in accordance with IPC/JEDEC standards), designed to ensure high assembly yield and long-term reliability._LQ: Can I use this sensor outdoors?_LA: Its operating temperature range is -25°C to +85°C, covering many outdoor conditions. However, direct exposure to sunlight (a strong source of infrared radiation) can saturate the phototransistor, causing false triggering. The device also lacks waterproof or dustproof sealing. For outdoor use, careful optical shielding to block ambient light and provision of environmental protection are necessary, or a different sensor technology may be more appropriate._CE9. Introduction to Working Principles

The slot-type photoelectric switch operates based on a simple photoelectric principle. It consists of two main components, mounted on opposite sides of a physical gap (the slot):
Infrared emitter (LED):

This is a semiconductor diode that emits infrared light (invisible to the human eye) when forward-biased with an appropriate current (e.g., 20mA).
Phototransistor:

This is a phototransistor. When photons from an infrared emitter strike its base region, electron-hole pairs are generated, which act as base current. This optically induced base current is amplified by the transistor's gain, resulting in a much larger collector current flowing from the collector to the emitter.

Operating Status:

1. Clear (Beam Present):Infrared light from the emitter shines directly on the phototransistor. The phototransistor turns on, allowing significant collector current (I
2. ) to flow. In a common-emitter circuit with a pull-up resistor, the collector output voltage is pulled low (close to V).

Obstructed (the light beam is blocked):
- An opaque object placed in the slot blocks the infrared light. No light reaches the phototransistor base, so it turns off. Only a tiny leakage current (I, dark current) flows. The collector's output voltage rises to near the supply voltage (V_).This switching between a high output voltage (beam blocked) and a low output voltage (beam clear) provides a clean digital signal for detection logic._{10. Development Trends}The field of photoelectric sensors, including slot-type photoelectric switches, continues to evolve. Observable objective trends within the industry include:
- Miniaturization:Continuous drive towards smaller package sizes (e.g., surface-mount devices with a smaller footprint and lower profile) to enable more compact end products and higher-density PCB assembly._CEOPerformance Enhancement:_CCUkuvuselelwa kwezinto zokwakha i-semiconductor kanye nokupakishwa kuhloswe ukunikeza ukuzwela okuphezulu (kuvumela amandla aphansi e-LED ukuze kuncishiswe ukusetshenziswa kwamandla), isikhathi sokuphendula esisheshayo ukuze sifanele izinhlelo zokusebenza ezisheshayo, kanye nokuzinza okungcono kwamazinga okushisa.

Ukuhlanganiswa Nokuhlakaniphile:

Ezinye izinto zokushintsha ze-slot photoelectric zesimanje zihlanganisa isifunda sokuqhuba i-LED kanye nokulungiswa kwesiginali ephumayo kwe-phototransistor (i-amplifier, i-comparator, i-Schmitt trigger) kungena kufakwe efakwe okufanayo. Lokhu kwenza lula ukuklanywa kwesifunda sangaphandle, futhi kunganikeza ukuphuma kwezinga le-logic yedijithali ngokuqondile. Ukuhlanganisa izinto eziningi zokuzwa nakho kuyisitayela.

Focus on Reliability and Manufacturing:

• Design increasingly prioritizes robustness against automated assembly processes (such as SMT and reflow soldering). Materials are selected to better resist thermal stress and environmental factors.Application-Specific Variants:
• Continuous development of sensors customized for specific market demands, such as ultra-thin sensors for paper handling in portable devices, or sensors with very narrow slots for high-precision edge detection.LTH-301-07P5 represents a mature and reliable technology that meets the core needs of a large number of standard applications, while these broader trends shape the development direction of next-generation devices.
• Integration and Smart Features:Some modern photo interrupters integrate the driver circuitry for the LED and signal conditioning (amplifier, comparator, Schmitt trigger) for the phototransistor output into the same package. This simplifies external circuit design and can provide a direct digital logic-level output. Integration of multiple sensing elements is also a trend.
• Focus on Reliability and Manufacturing:Designs increasingly prioritize robustness for automated assembly processes like pick-and-place and reflow soldering. Materials are selected for better resistance to thermal stress and environmental factors.
• Application-Specific Variants:Development continues for sensors tailored to specific market needs, such as ultra-thin sensors for paper handling in portable devices, or sensors with very narrow slots for high-precision edge detection.

The LTH-301-07P5 represents a mature and reliable technology that meets the core requirements for a wide array of standard applications, while these broader trends shape the development of next-generation devices.