onsemi KSA1175GTA

Overview

KSA1175GTA from Fairchild Semiconductor is a PNP epitaxial silicon transistor designed for low-frequency amplifier applications, with V_CEO = −50 V, I_C = −150 mA, P_C = 250 mW, h_FE range of 40–700 (depending on grade), and TO-92S package. It serves as a complement to the NPN KSC2785 in push-pull or differential pair configurations.

For engineers reviewing the KSA1175GTA datasheet, pinout, applications, or equivalent options, key selection criteria include its guaranteed h_FE classification (G-grade: 200–400), low V_CE(sat) (−0.18 V min at I_C = −100 mA / I_B = −10 mA), and noise figure (6.0–20 dB at 100 Hz), critical for audio preamplifier and signal conditioning stages.

Technical Context

The KSA1175GTA operates as a general-purpose PNP bipolar junction transistor optimized for linear amplification below 180 MHz (f_T up to 180 MHz). Its DC current gain is graded per h_FE binning (G = 200–400), and it features low saturation voltage and tight V_BE(on) tolerance (−0.50 to −0.80 V at I_E = −1 mA).

Designed for discrete analog signal paths, it supports stable biasing with I_CBO ≤ −0.1 µA and V_CB breakdown ≥ −60 V. Its Cob = 2.8 pF at V_CB = −10 V enables predictable high-frequency roll-off in tuned or broadband amplifier designs.

Key Specifications

Pinout & Package

Package: TO-92S - Small-outline, 3-lead plastic package with lead spacing 1.27 mm (0.05"), body height 3.72 mm, and footprint compatible with standard through-hole assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPSA92 and BC557B, the KSA1175GTA offers uniquely graded h_FE (G-bin), explicit complementarity to KSC2785, and TO-92S footprint - making it optimal for space-constrained, matched-pair, low-noise amplifier designs where gain predictability and thermal tracking are essential.

Availability

KSA1175GTA is available at Aetrix Electronics and suitable for audio pre-amplifiers, discrete voltage regulators, differential pair amplifiers, and LED constant-current sink circuits requiring stable component supply and consistent h_FE performance.

Supply support for KSA1175GTA 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The KSA1175GTA belongs to Fairchild's legacy PNP small-signal transistor family, engineered specifically for low-noise, low-frequency linear amplification and complementary circuit design in consumer and industrial analog systems.

FAQ

What is the h_FE range for KSA1175GTA?

The KSA1175GTA is graded as "G"-bin, with a guaranteed DC current gain (h_FE) range of 200 to 400 at V_CE = −6 V and I_C = −1 mA. This binning ensures consistent gain behavior across units, supporting reliable biasing in production audio and amplifier circuits without manual trimming. The full KSA1175 family spans h_FE classes R to L (40–700), but only the G-grade applies to KSA1175GTA.

Is KSA1175GTA pin-compatible with KSC2785?

No - KSA1175GTA (PNP) and KSC2785 (NPN) are complementary in electrical characteristics and application role, not pinout. KSA1175GTA uses E-B-C pin order (1=Emitter, 2=Collector, 3=Base) in TO-92S, while KSC2785 uses E-C-B in TO-92. Their complementarity lies in matched V_BE, h_FE, and f_T - enabling balanced performance in push-pull or differential stages - not mechanical interchangeability.

What is the maximum operating temperature for KSA1175GTA?

The KSA1175GTA has a maximum junction temperature (T_J) of 150°C and a storage temperature range of −55°C to +150°C. At ambient temperatures above 25°C, power dissipation must be derated linearly beyond 250 mW - typically at 2.0 mW/°C - to maintain safe junction operation. Thermal design should account for TO-92S's low thermal resistance to ambient (~300°C/W).

Does KSA1175GTA support audio-frequency amplification?

Yes - the KSA1175GTA is explicitly specified as a "Low Frequency Amplifier" in its datasheet, with f_T up to 180 MHz and noise figure as low as 6.0 dB at 100 Hz. Its h_FE stability, low V_CE(sat), and controlled Cob (2.8 pF) make it well-suited for high-fidelity audio pre-amplification, microphone biasing, and tone-control stages where linearity and SNR are critical.

What package type does KSA1175GTA use?

KSA1175GTA uses the TO-92S package - a compact, three-lead, through-hole plastic package with 1.27 mm lead pitch, 3.72 mm body height, and standardized E-B-C pinout (1=Emitter, 2=Collector, 3=Base). TO-92S is mechanically distinct from standard TO-92 (which has wider lead spacing and taller profile), and requires appropriate footprint and insertion tooling.