onsemi KSA1175OTA

Overview

KSA1175OTA from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon transistor designed for low-frequency amplification and switching in linear and driver stages. It features V_CEO = −50 V, I_C = −150 mA, P_C = 250 mW, h_FE range up to 700 (Class L), and f_T = 50–180 MHz - used in audio preamplifier input stages and relay drivers.

For engineers reviewing the KSA1175OTA datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, TO-92S package compatibility, guaranteed h_FE classification per batch marking (R/O/Y/G/L), V_CE(sat) ≤ −0.3 V at I_C = −100 mA/I_B = −10 mA, and noise figure of 6–20 dB at 100 Hz.

Technical Context

This device operates as a medium-power, low-noise PNP bipolar junction transistor with complementary pairing to the NPN KSC2785. Its DC current gain spans 40–700 depending on h_FE grade, and it maintains stable gain down to I_C = −0.3 mA while supporting f_T up to 180 MHz under V_CE = −6 V bias.

Designed for linear amplification, it delivers low V_BE(on) (−0.50 to −0.80 V) and tight V_CE(sat) (−0.18 to −0.3 V), enabling efficient Class-A and emitter-follower configurations in discrete analog signal chains where thermal stability and low distortion are critical.

Key Specifications

Pinout & Package

Package: TO-92S - compact, through-hole plastic package with 1.27 mm lead pitch, optimized for manual assembly and board-level reliability in consumer and industrial controls.

Key Features

Applications

Equivalent & Alternatives

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

Compared with KSA1175OTA, MPSA92 offers greater ruggedness at the cost of gain consistency and noise performance, while KSA992 trades voltage margin for current drive - neither is pin-compatible, and both require PCB layout revision and bias recalibration.

Availability

KSA1175OTA is available at Aetrix Electronics and suitable for audio preamplifiers, relay driver circuits, and differential pair amplifiers requiring stable component supply, consistent h_FE grading, and TO-92S footprint compatibility.

Supply support for KSA1175OTA 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud computing, and IoT applications.

The KSA1175OTA belongs to ON Semiconductor's legacy bipolar transistor portfolio, originally developed by Fairchild for general-purpose linear amplification and switching in cost-sensitive, high-reliability analog subsystems.

FAQ

What is the h_FE classification system for KSA1175OTA?

The KSA1175OTA is factory-binned into five h_FE ranges: R (40–80), O (70–140), Y (120–240), G (200–400), and L (350–700). Each unit is marked with its grade letter on the package. This allows designers to select units matching specific bias requirements without post-manufacture testing - critical for production consistency in discrete amplifier designs using KSA1175OTA.

Is KSA1175OTA pin-compatible with KSC2785?

No, KSA1175OTA and KSC2785 are complementary transistors (PNP vs. NPN) with identical TO-92S package pinout (Emitter–Collector–Base), but they are not electrically interchangeable. Their matching is functional - not physical - meaning they share mechanical footprint and thermal characteristics, enabling symmetrical PCB layout in push-pull or differential circuits using KSA1175OTA and KSC2785 together.

What is the maximum operating temperature for KSA1175OTA?

KSA1175OTA has a maximum junction temperature (T_J) of 150°C and storage temperature range of −55°C to +150°C. Derating begins above 25°C ambient: power dissipation must be reduced linearly to zero at 150°C case temperature. For continuous operation at full 250 mW, ensure case temperature remains ≤ 100°C via adequate copper area or airflow - verified in thermal characterization data for KSA1175OTA.

Does KSA1175OTA support audio-frequency amplification?

Yes, KSA1175OTA is explicitly characterized for low-frequency amplification with noise figure specified at 100 Hz (6–20 dB) and f_T up to 180 MHz. Its h_FE remains stable down to I_C = −0.3 mA, and V_BE(on) exhibits low hysteresis - making KSA1175OTA suitable for high-fidelity preamp stages, tone control networks, and active filters in consumer audio equipment.

What is the meaning of "OTA" suffix in KSA1175OTA?

The "OTA" suffix in KSA1175OTA denotes a specific tape-and-reel packaging variant compliant with EIA-481-D standards, intended for automated SMT placement despite the TO-92S through-hole form factor. It indicates moisture sensitivity level (MSL) 1, no bake requirement, and carrier tape pitch of 4 mm - distinct from bulk or ammo-pack versions. All electrical and thermal specs remain identical to the base KSA1175 part.