onsemi KST13MTF

Overview

KST13MTF from ON Semiconductor is an NPN epitaxial silicon Darlington transistor in SOT-23 package, rated for 30 V V_CEO, 300 mA I_C, and 350 mW P_C, with DC current gain (h_FE) of 5,000–10,000 at I_C = 10 mA and V_CE = 5 V, used in low-power signal amplification and interface driver circuits.

For engineers reviewing the KST13MTF datasheet, pinout, applications, or equivalent options, key selection criteria include its Darlington configuration for high current gain, SOT-23 footprint compatibility, V_CE(sat) ≤ 1.5 V at I_C = 100 mA/I_B = 0.1 mA, f_T = 125 MHz, and ESD robustness per standard JEDEC ratings.

Technical Context

The KST13MTF implements a monolithic Darlington pair-two cascaded NPN transistors-with base-emitter shunt resistor omitted, enabling high DC current gain while retaining fast switching capability via f_T = 125 MHz at 10 mA collector bias. Its V_BE(on) = 2.0 V reflects the stacked base-emitter junction voltage drop.

Designed for low-voltage, low-current amplification and digital logic interfacing, it operates within absolute maximum ratings of 30 V V_CBO/V_CEO, 10 V V_EBO, and 150 °C T_STG, with leakage currents ICBO ≤ 100 nA and IEBO ≤ 100 nA under specified test conditions.

Key Specifications

Pinout & Package

SOT-23 surface-mount plastic package with gull-wing leads; standardized 3-pin footprint (JEDEC MO-215), 1.3 mm × 2.9 mm body size, 0.95 mm height, and 0.95 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMDT2907A and NSVT1319M3T5G, the KST13MTF offers the highest guaranteed h_FE range among SOT-23 Darlington transistors, making it optimal for ultra-low-base-drive applications, while NSVT1319M3T5G adds AEC-Q101 compliance without sacrificing electrical performance.

Availability

KST13MTF is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface stages, small-signal amplifiers, and relay driver modules requiring stable component supply across industrial, consumer, and embedded design cycles.

Supply support for KST13MTF 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 (formerly Fairchild Semiconductor) is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices, with broad distribution and automotive-grade qualification capabilities.

The KST13MTF belongs to ON Semiconductor's legacy SOT-23 discrete transistor family, designed specifically for cost-sensitive, space-constrained applications needing high DC gain and reliable low-voltage switching performance.

FAQ

What is the maximum collector-emitter voltage rating for KST13MTF?

The KST13MTF has a maximum collector-emitter voltage (V_CEO) rating of 30 V, verified per its absolute maximum ratings table. This value applies at T_A = 25 °C with proper PCB thermal relief. Exceeding 30 V risks avalanche breakdown and permanent device failure. Derating is required above 25 °C ambient per the datasheet's thermal curves. The KST13MTF must not be used in circuits where transient spikes exceed this limit without clamping protection.

Does KST13MTF have built-in base-emitter resistors?

No, the KST13MTF does not include internal base-emitter resistors. It is a bare Darlington pair requiring external base biasing-either via series resistor from drive source or active current source. This differs from "digital transistors" like the NSVD120N3T1G, which integrate R₁/R₂. The absence of on-chip resistors gives designers full control over base current and switching speed but mandates careful external bias network design for the KST13MTF.

What is the typical DC current gain (h_FE) of KST13MTF at 10 mA collector current?

The typical DC current gain (h_FE) of the KST13MTF is 5,000–10,000 when measured at V_CE = 5 V and I_C = 10 mA, per its published electrical characteristics. This wide range reflects process variation across wafers; design margins should assume minimum h_FE = 5,000. The KST13MTF achieves this gain through monolithic Darlington integration-not discrete cascading-ensuring consistent phase and thermal tracking between stages.

Is KST13MTF pin-compatible with other SOT-23 NPN transistors?

The KST13MTF uses standard SOT-23 pinout (1=Base, 2=Emitter, 3=Collector), matching industry convention for NPN devices in that package. However, pin compatibility alone does not guarantee functional equivalence-e.g., MMBT2222A has different h_FE, V_CE(sat), and f_T. For reliable substitution, verify all key parameters including Darlington topology, gain range, and saturation voltage before replacing another part with KST13MTF.

What is the thermal resistance (R_θJA) of KST13MTF in standard SOT-23 mounting?

The KST13MTF does not publish a specific R_θJA value in its datasheet, but typical SOT-23 packages with minimal copper pad achieve R_θJA ≈ 300–350 °C/W. With 25 mm² of 1-oz copper connected to the emitter pad, R_θJA improves to ~200 °C/W. Since the KST13MTF has P_C = 350 mW, even at 200 °C/W, ΔT = 70 °C rise above ambient-requiring derating above 55 °C ambient. Always validate thermal performance empirically for the KST13MTF in your layout.