Toshiba Semiconductor and Storage TLP170A(TP,F)

Overview

TLP170A(TP,F) from Toshiba Electronic Devices & Storage Corporation is a normally-open photorelay IC comprising an infrared LED optically coupled to a photo-MOSFET in a 4-pin SOP package. It requires only 1 mA LED trigger current, delivers up to 400 mA ON-state current with ≤2 Ω R_ON, and supports 60 V OFF-state voltage - ideal for low-power mechanical relay replacement in industrial control interfaces.

For engineers reviewing the TLP170A(TP,F) datasheet, TLP170A(TP,F) pinout, TLP170A(TP,F) application, or TLP170A(TP,F) equivalent, key selection criteria include isolation voltage (1500 V_rms), thermal derating behavior (−4.0 mA/°C for I_ON), SOP-4 package compatibility, and UL/cUL safety certification under UL 1577 and CSA 5A.

Technical Context

The TLP170A(TP,F) implements optical isolation between input and output stages using gallium arsenide (GaAs) LED and silicon MOSFET die, with pins 1–2 electrically shorted as the LED anode–cathode pair and pins 3–4 shorted as the MOSFET drain terminals. Its internal structure enforces single-pole, single-throw (1-Form-A) switching behavior without gate drive circuitry.

It operates within −40 °C to +85 °C ambient temperature, supports up to 48 V supply voltage, and exhibits measured switching times of 3.0–8.0 ms turn-on and 1.0–3.0 ms turn-off at V_DD = 20 V and R_L = 200 Ω - confirming suitability for moderate-speed, low-noise signal path isolation in factory automation and security equipment.

Key Specifications

Pinout & Package

Package: SOP-4 (2.54 mm pitch, 2.1 mm height, JEDEC MS-012 variant 11-5H1S), surface-mount, tape-and-reel packaged (TP,F designation).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar photorelay applications.

Compared with TLP170G(TP,F), the TLP170A(TP,F) trades 40 V OFF-state headroom for tighter production tolerances and broader safety certification; versus PS7141-AL, it provides higher current rating, lower R_ON, and dual UL/cUL listing - making it preferred for certified industrial and telecom designs.

Availability

TLP170A(TP,F) is available at Aetrix Electronics and suitable for factory automation (FA), security equipment, measuring instruments, and private branch exchanges (PBXs) requiring stable component supply, long-lifecycle support, and certified isolation performance.

Supply support for TLP170A(TP,F) includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Toshiba Electronic Devices & Storage Corporation designs and manufactures discrete semiconductors, power devices, and optoelectronics for industrial, automotive, and consumer applications.

The TLP170A(TP,F) belongs to Toshiba's photorelay product line, engineered specifically to replace electromechanical relays in space-constrained, high-reliability industrial control and telecom interface applications.

FAQ

What is the maximum allowable ambient temperature for continuous operation of the TLP170A(TP,F)?

The TLP170A(TP,F) is rated for continuous operation from −40 °C to +85 °C ambient temperature. At temperatures above 25 °C, the ON-state current must be derated by −4.0 mA/°C per the absolute maximum ratings table. This linear derating ensures junction temperature remains below 125 °C under worst-case power dissipation. The TLP170A(TP,F) datasheet provides Fig.12.2 (I_ON vs. T_a) for precise margining in thermally constrained enclosures.

Does the TLP170A(TP,F) support direct connection to a 3.3 V microcontroller GPIO without external components?

Yes - the TLP170A(TP,F) has a maximum trigger LED current (I_FT) of 1 mA, and its typical forward voltage (V_F) is 1.15 V at 10 mA. When driven from a 3.3 V GPIO, a 2.2 kΩ series resistor limits current to ~1 mA, satisfying the turn-on requirement without additional active circuitry. This direct-drive capability is confirmed in the Recommended Operating Conditions section of the TLP170A(TP,F) datasheet.

What safety certifications does the TLP170A(TP,F) hold, and what do they cover?

The TLP170A(TP,F) is UL-recognized under UL 1577 (File No. E67349) and cUL-recognized under CSA Component Acceptance Service No.5A (File No. E67349). These certifications validate the device's 1500 V_rms isolation withstand voltage, creepage and clearance distances, and construction integrity for use in industrial equipment. Both listings apply to the TLP170A(TP,F) in its standard SOP-4 package without modification.

How does the internal pin shorting (Pins 3 and 4) affect PCB layout for the TLP170A(TP,F)?

Pins 3 and 4 of the TLP170A(TP,F) are internally shorted as dual drain terminals, allowing either pin to carry the full 400 mA ON-state current. In PCB layout, this permits flexible copper pour routing - both pins should be connected to the same net (e.g., load return path), and wide traces or thermal pads are recommended to manage power dissipation. The internal short eliminates need for external paralleling and simplifies layout versus discrete MOSFET solutions.

Can the TLP170A(TP,F) safely switch AC loads, or is it limited to DC?

The TLP170A(TP,F) is specified for DC switching only: its OFF-state voltage rating (60 V min) and ON-state current (400 mA max) apply to unidirectional loads. It lacks zero-crossing detection or bidirectional blocking capability, and its internal MOSFET structure is optimized for DC conduction. Attempting AC switching may cause premature failure due to reverse-bias stress on the output stage. For AC loads, Toshiba recommends dedicated AC-output phototriacs such as the TLP360J series instead of the TLP170A(TP,F).