NXP Semiconductors BT169D-L,112

Overview

BT169D-L,112 from NXP Semiconductors is a planar passivated silicon controlled rectifier (SCR) in SOT54 (TO-92) package, designed for low-power latching and protection circuits. It features 400 V repetitive peak off-state voltage (VDRM), 50 µA maximum gate trigger current (IGT), and 0.8 A RMS on-state current (IT(RMS)), enabling reliable operation in lighting ballast shut-down and SMPS protection.

For engineers reviewing the BT169D-L,112 datasheet, BT169D-L,112 pinout, BT169D-L,112 application, or BT169D-L,112 equivalent, key selection criteria include sensitive gate triggering (≤50 µA), low holding current (0.4–1 mA), thermal resistance to lead (60 K/W), and TO-92 through-hole compatibility for cost-sensitive industrial control designs.

Technical Context

The BT169D-L,112 operates as a unidirectional thyristor with planar passivation ensuring voltage ruggedness up to 400 V in both forward and reverse blocking modes. Its very sensitive gate enables triggering with sub-100 µA currents under standard test conditions (VD = 12 V, IT = 10 mA, Tj = 25 °C).

It supports half-sine wave conduction with IT(RMS) = 0.8 A at Tlead ≤ 83 °C and withstands non-repetitive surge currents up to 8 A (10 ms, Tj(init) = 25 °C). Critical dVD/dt capability reaches 800 V/µs at Tj = 125 °C with gate resistor RGK = 1 kΩ, minimizing false turn-on in noisy environments.

Key Specifications

Pinout & Package

SOT54 (TO-92) plastic single-ended leaded through-hole package with 3 leads; body dimensions: 5.2 × 4.8 × 14.5 mm (L × D × L), lead pitch 2.54 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BT169G,112, the BT169D-L,112 offers superior gate sensitivity for microcontroller-driven systems; versus TYN104, it provides TO-92 cost and size advantages at the expense of thermal headroom and current capacity.

Availability

BT169D-L,112 is available at Aetrix Electronics and suitable for lighting ballast protection, SMPS shut-down circuits, and low-power latching applications requiring stable component supply across industrial OEM production runs.

Supply support for BT169D-L,112 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The BT169D-L,112 belongs to NXP's legacy discrete thyristor product line, engineered specifically for cost-sensitive, low-power AC/DC control and protection functions in consumer and industrial equipment.

FAQ

What is the maximum gate trigger current specification for BT169D-L,112?

The BT169D-L,112 has a maximum gate trigger current (IGT) of 50 µA under standard test conditions (VD = 12 V, IT = 10 mA, Tj = 25 °C). This value is confirmed in Table 1 and Table 6 of the NXP datasheet Rev. 6. The BT169D-L,112 maintains this low IGT across its operating temperature range, making it suitable for direct microcontroller GPIO triggering without external amplification.

Can BT169D-L,112 be used in 230 V AC lighting ballast protection circuits?

Yes, the BT169D-L,112 supports 400 V repetitive peak off-state voltage (VDRM) and reverse voltage (VRRM), providing sufficient margin above 230 V AC peak (≈325 V). Its 800 V/µs dVD/dt rating and planar passivation ensure reliable blocking and noise immunity in ballast environments. The BT169D-L,112 is explicitly cited in NXP's application notes for lighting protection use cases.

What is the thermal resistance from junction to lead for BT169D-L,112?

The thermal resistance from junction to lead (Rth(j-lead)) for BT169D-L,112 is 60 K/W, per Table 5 of the NXP datasheet. This parameter is measured with the device mounted on a PCB using standard lead length (4 mm), and it directly informs heatsinking requirements when operating near IT(RMS) = 0.8 A. The BT169D-L,112 relies primarily on lead conduction rather than ambient convection for thermal dissipation.

Does BT169D-L,112 have a specified non-repetitive peak on-state current rating?

Yes, the BT169D-L,112 has a non-repetitive peak on-state current (ITSM) rating of 8 A for a 10 ms half-sine wave pulse at Tj(init) = 25 °C, as stated in Table 1 and Table 4. This rating applies to transient overload events such as capacitor discharge in ignition circuits. The BT169D-L,112 also supports 9 A for 8.3 ms pulses, confirming its suitability for short-duration surge handling.

How does the holding current of BT169D-L,112 affect latching reliability in low-current applications?

The BT169D-L,112 has a holding current (IH) range of 0.4–1 mA at Tj = 25 °C, per Table 6. This low IH ensures stable latched conduction even when load current drops below 1 mA - critical for battery-powered latching relays or sensor-triggered shut-down circuits. The BT169D-L,112 maintains functional latching down to 0.4 mA, minimizing risk of unintended turn-off during current dips.