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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi MMBTA70LT1G

Name: MMBTA70LT1G
Brand: onsemi
SKU: MMBTA70LT1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBTA70LT1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: MMBTA70LT1G.pdf

Description:: TRANS PNP 40V 0.1A SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MMBTA70LT1G from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −40 V V_CEO, −100 mA I_C, and 225 mW power dissipation on FR-5 board. It delivers h_FE = 40–400 at −5 mA I_C, V_CE(sat) ≤ −0.25 V at −10 mA I_C/−1 mA I_B, and f_T = 125 MHz - enabling use in low-power linear amplification and switching circuits in consumer and industrial signal conditioning.

For engineers reviewing the MMBTA70LT1G datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, thermal derating behavior, noise performance curves, SOT-23 terminal mapping, and validated alternative transistors for discrete analog design and replacement sourcing.

Technical Context

This PNP bipolar junction transistor operates with emitter-base forward bias and collector-emitter reverse bias in active or saturation mode. Its DC current gain spans 40–400 across −0.001 to −100 mA I_C, and its 125 MHz f_T supports RF amplification up to VHF band when biased at −5 mA I_C and −10 V V_CE. Thermal resistance is 556 °C/W (FR-5) or 417 °C/W (alumina), enabling predictable junction temperature rise under pulsed or continuous load.

Small-signal characteristics include C_obo ≤ 4.0 pF at −10 V V_CB, and noise figures are specified across 100 Hz–1 kHz bandwidths with source resistance dependence shown in Figures 3–5. The device exhibits −55°C to +150°C T_J/T_stg range and meets RoHS, Pb-free, and halogen-free compliance requirements.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−40 V - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in PNP switch or amplifier stages.
I_C (max)	−100 mA - Continuous collector current rating; sets maximum load drive capability in low-side switching or current-source applications.
P_D (FR-5)	225 mW at 25°C - Power dissipation limit on standard PCB; requires 1.8 mW/°C derating above ambient for thermal safety.
h_FE	40–400 - Wide DC current gain range at −5 mA I_C/−10 V V_CE; enables stable biasing across production lots and temperature.
V_CE(sat)	≤ −0.25 V at −10 mA I_C/−1 mA I_B - Low saturation voltage minimizes conduction loss in switching applications.
f_T	125 MHz - Transition frequency confirms usable gain-bandwidth for audio preamps and narrowband RF amplifiers.
C_obo	≤ 4.0 pF at −10 V V_CB - Output capacitance impacts high-frequency stability and bandwidth in tuned circuits.

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm body with 1.90 mm lead pitch. JEDEC case 318, style 6 marking: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Current-controlled input node	Receives base drive current to modulate collector-emitter conduction; requires series resistor for current limiting in digital switch applications.
2 (Emitter)	PNP emitter terminal	Connected to higher potential rail in common-emitter configuration; serves as reference node for bias network and current sensing.
3 (Collector)	Output current terminal	Delivers amplified or switched current to load; polarity must be negative relative to emitter in active operation.

Key Features

Feature	Design Value
Pb-free, Halogen-free, RoHS-compliant	Meets global environmental regulations without requiring process requalification for lead-free assembly.
Low V_CE(sat) (≤ −0.25 V)	Reduces power loss and self-heating in battery-powered PNP switch designs operating near 3.3 V or 5 V rails.
High f_T (125 MHz)	Supports stable small-signal amplification up to VHF frequencies when used with proper neutralization and layout.
Wide h_FE range (40–400)	Enables robust circuit operation across manufacturing variance and temperature drift without active bias compensation.
Low C_obo (≤ 4.0 pF)	Minimizes Miller effect in high-gain amplifier stages, preserving phase margin and reducing oscillation risk.

Applications

Audio Pre-amplifier Stage	Low-Voltage Level Shifter
Use Scenario: Amplifying microphone or sensor signals in portable audio devices with single-supply 3.3 V operation. IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–40 dB voltage gain with minimal distortion at 20 Hz–20 kHz. Use Value: High h_FE and low noise current enable SNR > 75 dB at 1 kHz with 1 kΩ source impedance per Figure 4.	Use Scenario: Converting 1.8 V logic outputs to interface with 5 V or −5 V analog subsystems in mixed-voltage microcontroller systems. IC Role / Device Role / Timing Role: Active level translator using emitter-follower or common-base configuration for bidirectional voltage translation. Use Value: V_CEO = −40 V and low V_CE(sat) allow reliable operation across wide output swing while maintaining fast edge integrity.
LED Current Sink Driver	Discrete Voltage Regulator Error Amplifier
Use Scenario: Driving indicator LEDs or low-current optocouplers in industrial control panels with 12 V supply rails. IC Role / Device Role / Timing Role: Saturated PNP switch controlling LED anode connection to positive rail via emitter follower or common-emitter topology. Use Value: −100 mA I_C rating and 225 mW P_D support driving multiple LEDs with <100 Ω ballast resistors without thermal throttling.	Use Scenario: Implementing error amplification in linear voltage regulators or feedback loops for precision analog power supplies. IC Role / Device Role / Timing Role: Transconductance stage comparing reference and output voltages to adjust pass element bias. Use Value: Stable h_FE over temperature and low input capacitance ensure loop stability and <1% regulation error across load transients.

Audio Pre-amplifier Stage

Low-Voltage Level Shifter

Use Scenario: Amplifying microphone or sensor signals in portable audio devices with single-supply 3.3 V operation.

IC Role / Device Role / Timing Role: PNP common-emitter amplifier providing 20–40 dB voltage gain with minimal distortion at 20 Hz–20 kHz.

Use Value: High h_FE and low noise current enable SNR > 75 dB at 1 kHz with 1 kΩ source impedance per Figure 4.

Use Scenario: Converting 1.8 V logic outputs to interface with 5 V or −5 V analog subsystems in mixed-voltage microcontroller systems.

IC Role / Device Role / Timing Role: Active level translator using emitter-follower or common-base configuration for bidirectional voltage translation.

Use Value: V_CEO = −40 V and low V_CE(sat) allow reliable operation across wide output swing while maintaining fast edge integrity.

LED Current Sink Driver

Discrete Voltage Regulator Error Amplifier

Use Scenario: Driving indicator LEDs or low-current optocouplers in industrial control panels with 12 V supply rails.

IC Role / Device Role / Timing Role: Saturated PNP switch controlling LED anode connection to positive rail via emitter follower or common-emitter topology.

Use Value: −100 mA I_C rating and 225 mW P_D support driving multiple LEDs with <100 Ω ballast resistors without thermal throttling.

Use Scenario: Implementing error amplification in linear voltage regulators or feedback loops for precision analog power supplies.

IC Role / Device Role / Timing Role: Transconductance stage comparing reference and output voltages to adjust pass element bias.

Use Value: Stable h_FE over temperature and low input capacitance ensure loop stability and <1% regulation error across load transients.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT3906LT1G	Lower V_CEO (−40 V same), but h_FE = 100–300 (narrower range); f_T = 250 MHz; C_obo = 4.5 pF.	Better high-frequency response but tighter h_FE tolerance; preferred for RF switching where gain consistency matters more than wide-range bias stability.	Select MMBT3906LT1G when f_T > 125 MHz is required and h_FE variation < ±20% is acceptable.
BC807-25LT1G	Higher I_C (−500 mA), same V_CEO (−45 V), h_FE = 160–400, P_D = 310 mW (SOT-23).	Higher power handling and gain consistency; suited for higher-current switching where MMBTA70LT1G would thermally saturate.	Choose BC807-25LT1G when load current exceeds −100 mA or board-level thermal mass is limited.

Compared with MMBTA70LT1G, MMBT3906LT1G offers superior RF performance but narrower DC gain spread, while BC807-25LT1G trades off footprint compatibility for significantly higher current and power capability - making each suitable for distinct trade-offs in gain stability, frequency, or thermal headroom.

Availability

MMBTA70LT1G is available at Aetrix Electronics and suitable for audio preamplification, low-voltage level shifting, LED current sinking, and discrete voltage regulator error amplification requiring stable component supply and RoHS-compliant packaging.

Supply support for MMBTA70LT1G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MMBTA70LT1G belongs to onsemi's general-purpose bipolar transistor product line, designed for cost-sensitive, space-constrained linear and switching applications where reliability, consistent h_FE, and low-noise performance are critical.

FAQ

What is the maximum collector-emitter voltage rating for MMBTA70LT1G?

The MMBTA70LT1G has a guaranteed minimum V_(BR)CEO of −40 Vdc at I_C = −1.0 mAdc and I_B = 0. This rating defines the absolute maximum reverse-biased voltage the transistor can withstand between collector and emitter without breakdown. Exceeding −40 V risks permanent damage, and design margins should maintain operation below −36 V in production circuits.

Does MMBTA70LT1G support lead-free reflow soldering processes?

Yes, MMBTA70LT1G is explicitly marked Pb-free and RoHS-compliant per its datasheet revision 4 (November 2024). It is qualified for standard lead-free reflow profiles including JEDEC J-STD-020, with peak temperatures up to 260°C. The SOT-23 package uses matte tin plating compatible with no-clean and water-soluble flux chemistries.

What is the typical noise performance of MMBTA70LT1G at 1 kHz?

At V_CE = −5.0 Vdc and T_A = 25°C, MMBTA70LT1G exhibits a noise figure of approximately 1.0 dB at 1 kHz with 1 kΩ source resistance (per Figure 4). Its noise current is ~1.0 pA/√Hz, making it suitable for low-noise preamplifier stages where signal sources have impedances between 100 Ω and 10 kΩ.

Can MMBTA70LT1G be used in common-emitter amplifier configurations?

Yes, MMBTA70LT1G is routinely deployed in common-emitter amplifier topologies. With h_FE = 40–400 at −5 mA I_C, it delivers predictable voltage gain and phase inversion. Designers must ensure proper emitter degeneration and collector load selection to maintain stability, especially above 10 MHz where f_T = 125 MHz begins to limit open-loop gain.

How does thermal derating work for MMBTA70LT1G on a standard FR-5 PCB?

On FR-5 board at T_A = 25°C, MMBTA70LT1G's P_D is 225 mW, derating linearly by 1.8 mW/°C above 25°C. At 75°C ambient, maximum allowable dissipation drops to 225 − (50 × 1.8) = 135 mW. This reflects R_JA = 556 °C/W, so junction temperature rise ΔT_J = P_D × 556 must stay below 150°C − T_A for reliability.

MMBTA70LT1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 1mA, 10mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 5mA, 10V

Power - Max:: 225 mW

Frequency - Transition:: 125MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

MMBTA70LT1G FAQ

1.How can I place an order for MMBTA70LT1G through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBTA70LT1G on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MMBTA70LT1G reliable?

The price and inventory of MMBTA70LT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBTA70LT1G is usually 5 days.

3.What payment methods are accepted for MMBTA70LT1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBTA70LT1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBTA70LT1G?

MMBTA70LT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBTA70LT1G order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MMBTA70LT1G?

For technical support, including MMBTA70LT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBTA70LT1G requirements.

6.How does Aetrix verify that MMBTA70LT1G is sourced from the original manufacturer or authorized distributors?

All MMBTA70LT1G products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MMBTA70LT1G meets industry standards.

7.What is the process for return or replacement of MMBTA70LT1G?

All MMBTA70LT1G units undergo pre-shipment inspection (PSI). If there is an issue with MMBTA70LT1G, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MMBTA70LT1G part is unused and in its original packaging.

Return procedure for MMBTA70LT1G:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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