onsemi KSA1175RTA

Overview

KSA1175RTA from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon transistor designed for low-frequency amplification and switching in analog signal paths. It features V_CEO = −50 V, I_C = −150 mA, P_C = 250 mW, h_FE = 40–700 (R–L grade), and f_T = 50–180 MHz - enabling use in audio preamplifiers, relay drivers, and discrete logic level translation.

For engineers reviewing the KSA1175RTA datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92S package, complementary pairing with KSC2785, guaranteed h_FE classification band, V_CE(sat) ≤ −0.3 V at I_C = −100 mA/I_B = −10 mA, and noise figure of 6.0–20 dB at 100 Hz.

Technical Context

This PNP bipolar junction transistor operates in common-emitter configuration with DC current gain spanning five factory-classified bins (R to L). Its breakdown ratings - BVCBO = −60 V, BVCEO = −50 V, BVEBO = −5 V - define safe operating limits under reverse-biased junction conditions.

Dynamic performance is characterized by f_T up to 180 MHz and Cob = 2.8 pF at V_CB = −10 V, supporting stable gain in sub-VHF amplification stages. Saturation behavior is specified at I_C/I_B = 10, with V_CE(sat) ≤ −0.3 V and V_BE(on) = −0.50 to −0.80 V at I_E = −1 mA.

Key Specifications

Pinout & Package

Package: TO-92S - 3-lead plastic through-hole package with 1.27 mm lead pitch, 4.00 mm body height, and 2.86 mm body width; optimized for manual assembly and compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPSA92 and BC557, the KSA1175RTA offers factory-grade h_FE binning, documented noise performance, and guaranteed complementary pairing - making it preferable for precision low-noise or matched-pair analog designs despite narrower absolute ratings.

Availability

KSA1175RTA is available at Aetrix Electronics and suitable for audio preamplifiers, relay driver circuits, and discrete logic level translators requiring stable component supply, consistent h_FE grading, and TO-92S through-hole compatibility.

Supply support for KSA1175RTA 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, medical, and IoT applications.

The KSA1175RTA belongs to ON Semiconductor's legacy bipolar transistor portfolio, originally developed by Fairchild for general-purpose low-frequency amplification and switching - emphasizing reliability, parameter consistency, and complementary device pairing.

FAQ

What is the pin configuration of the KSA1175RTA?

The KSA1175RTA uses a TO-92S package with standardized pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. This configuration is confirmed in the original Fairchild Rev. A2 datasheet and maintained in ON Semiconductor's documentation. Correct orientation is essential - reversing emitter and collector will exceed V_EBO rating and cause immediate failure. Always verify physical marking alignment before soldering the KSA1175RTA.

Is the KSA1175RTA RoHS compliant?

Yes, the KSA1175RTA is RoHS compliant and lead-free, consistent with ON Semiconductor's transition to green packaging standards post-2006. The TO-92S package uses matte tin plating on leads and halogen-free molding compound. Compliance is verified per JEDEC J-STD-609 and reflected in ON Semiconductor's official part status documentation for KSA1175RTA - no exemptions apply.

What does the 'RTA' suffix mean in KSA1175RTA?

The 'RTA' suffix in KSA1175RTA denotes a specific tape-and-reel packaging variant for automated SMT placement, with 2,000 units per reel and moisture sensitivity level (MSL) 1. It does not indicate a parametric change - all electrical specifications match the base KSA1175. The 'R' signifies reel packaging, 'T' indicates tape carrier, and 'A' identifies the standard moisture barrier specification. This applies exclusively to the KSA1175RTA, not other variants like KSA1175OTA (ammo pack).

Can KSA1175RTA replace KSA1175 in existing designs?

Yes, KSA1175RTA is a direct form-fit-function replacement for KSA1175, sharing identical die, TO-92S package dimensions, pinout, and electrical specifications. The only difference is packaging format: KSA1175RTA is supplied on tape-and-reel for pick-and-place machines, while KSA1175 is typically in bulk or ammo packs. No layout or schematic changes are needed when substituting KSA1175RTA into a design originally specifying KSA1175.

What is the maximum operating temperature for KSA1175RTA?

The KSA1175RTA has a maximum junction temperature (T_J) of 150°C and storage temperature range of −55°C to +150°C. For reliable long-term operation, the device must be derated according to its thermal resistance (R_θJA ≈ 400°C/W for TO-92S on FR-4 with minimal copper). At ambient temperatures above 70°C, power dissipation must be reduced below 250 mW to prevent exceeding T_J = 150°C - always reference the KSA1175RTA thermal curves in the official datasheet.