NXP Semiconductors PDTA123JS,126

Overview

PDTA123JS from NXP Semiconductors is a PNP resistor-equipped transistor with integrated bias resistors R1 = 2.2 kΩ and R2 = 47 kΩ, designed for general-purpose switching in low-voltage DC circuits. It features V_CEO = −50 V, I_O = −100 mA, and V_CEsat ≤ −100 mV at I_C = −5 mA / I_B = −0.25 mA, enabling compact level-shifting and logic interface applications in space-constrained through-hole designs.

For engineers reviewing the PDTA123JS datasheet, PDTA123JS pinout, PDTA123JS application, or PDTA123JS equivalent, key selection criteria include its TO-92 (SOT54) through-hole package, built-in resistor ratio (R2/R1 ≈ 21), input-off voltage (V_i(off) = −0.6 V typical), and thermal resistance (R_{th j-a} = 250 K/W), all critical for reliable discrete logic buffering and load driving without external bias networks.

Technical Context

This device integrates two precision on-chip resistors to form a fixed-base-bias network, eliminating external components while maintaining predictable turn-on/off thresholds. Its PNP topology supports active-low switching, emitter-follower buffering, and open-collector-compatible output stages.

The SOT54 (TO-92) package provides mechanical robustness and thermal performance suitable for ambient temperatures from −65 °C to +150 °C, with P_tot = 500 mW at T_amb ≤ 25 °C - enabling use in industrial control modules and legacy board replacements where leaded packages are required.

Key Specifications

Pinout & Package

SOT54 (TO-92) is a 3-lead through-hole plastic package with standard lead spacing (e = 2.54 mm), body dimensions 4.8 × 4.2 × 14.5 mm, and axial lead orientation optimized for manual assembly and wave soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP resistor-equipped transistor applications.

Compared with PDTC123JS and NSV123JS, PDTA123JS offers higher guaranteed h_FE (≥100), making it preferable for margin-critical industrial interfaces, while its TO-92 footprint ensures drop-in replacement in legacy through-hole assemblies without rework.

Availability

PDTA123JS is available at Aetrix Electronics and suitable for industrial control modules, legacy equipment repair, and embedded logic interface circuits requiring stable component supply and long-term obsolescence management.

Supply support for PDTA123JS 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 applications.

The PDTA123J series belongs to NXP's resistor-equipped transistor (RET) product line, engineered to simplify discrete logic interface design by integrating precision bias networks into standard bipolar packages.

FAQ

What is the maximum continuous collector current rating for PDTA123JS?

The PDTA123JS has a maximum DC output current (I_O) rating of −100 mA, verified under standard mounting conditions with ambient temperature ≤25 °C. This rating applies to steady-state conduction in common-emitter configurations and must be derated linearly above 25 °C ambient per the thermal resistance specification (R_{th j-a} = 250 K/W). Exceeding this limit risks thermal runaway or permanent degradation of the PDTA123JS junction.

Does PDTA123JS require external bias resistors for basic switching operation?

No, the PDTA123JS does not require external bias resistors because it integrates R1 = 2.2 kΩ and R2 = 47 kΩ internally between base, emitter, and collector terminals. This built-in network establishes a fixed base current path that enables direct connection to logic-level inputs (e.g., 3.3 V or 5 V microcontroller pins), eliminating two discrete components and simplifying PCB layout for the PDTA123JS in digital interface roles.

What is the pin configuration of PDTA123JS in its SOT54 (TO-92) package?

The PDTA123JS uses a standardized SOT54 (TO-92) pinout: Pin 1 is Base, Pin 2 is Collector, and Pin 3 is Emitter - confirmed in the "Simplified outline, symbol and pinning" section of the official NXP datasheet. This arrangement supports common-emitter switching topologies where the emitter is grounded and the collector drives the load, and is mechanically compatible with legacy TO-92 sockets and wave-soldering fixtures used for the PDTA123JS.

Can PDTA123JS be used as a direct replacement for standard PNP transistors like BC557?

No, PDTA123JS cannot serve as a direct replacement for standard PNP transistors such as BC557 because it includes internal bias resistors that alter its input impedance and drive requirements. While both are PNP devices in TO-92 packages, the PDTA123JS expects logic-level voltage drive at the base pin and lacks the flexibility of externally adjustable biasing. Substituting the PDTA123JS for BC557 would require circuit redesign to accommodate its fixed R1/R2 network.

What is the typical input-off voltage (V_i(off)) for PDTA123JS and why does it matter?

The typical input-off voltage (V_i(off)) for PDTA123JS is −0.6 V, with a maximum of −0.5 V, defined as the base-emitter voltage below which collector current drops to ≤100 μA. This parameter ensures reliable cutoff when driven by standard CMOS or TTL logic low states, preventing leakage-induced false triggering in noise-sensitive applications - a critical design assurance for stable operation of the PDTA123JS in industrial control and instrumentation circuits.