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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Bipolar Transistor Arrays

STMicroelectronics L6221CD013TR

Name: L6221CD013TR
Brand: STMicroelectronics
SKU: L6221CD013TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6221CD013TR

Manufacturer:: STMicroelectronics

Category:: Bipolar Transistor Arrays

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: L6221CD013TR.pdf

Description:: TRANS 4NPN DARL 60V 1.2A 20-SO

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Product details

Overview

L6221CD013TR from STMicroelectronics is a monolithic quad Darlington switch IC designed for high-voltage, high-current inductive load switching. It features four non-inverting TTL-compatible inputs with a common enable, 60 V output voltage rating, 1.8 A continuous per-channel collector current, and integrated fast recirculation diodes. It is used in industrial solenoid drivers and relay interface modules where robust clamping and parallel channel operation are required.

For engineers reviewing the L6221CD013TR datasheet, L6221CD013TR pinout, L6221CD013TR application, or L6221CD013TR equivalent, key selection criteria include per-channel saturation voltage (1.4 V @ 1 A), clamp diode forward voltage (1.8 V @ 1 A), thermal resistance (R_{th j-amb} = 35 °C/W in SO20), and enable-controlled channel grouping for synchronized switching.

Technical Context

The L6221CD implements four independent open-collector Darlington output stages sharing a common emitter (GND) and logic supply (VS). Each channel integrates a fast freewheeling diode between OUTx and CLAMPx terminals to manage inductive kickback without external components.

Its TTL-compatible inputs (V_INH ≥ 2 V, V_INL ≤ 0.8 V) allow direct interfacing with microcontrollers and logic families. The single ENABLE input gates all four outputs simultaneously, supporting coordinated turn-on/turn-off timing critical for multi-solenoid sequencing.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	60 V - supports solenoids, relays, and DC motors up to 60 V bus voltage
Continuous Output Current	1.8 A per channel - enables driving medium-power inductive loads without external current boosting
V_CE(sat)	1.4 V @ I_C = 1 A - low conduction loss reduces heat generation and improves efficiency
Clamp Diode V_F	1.8 V @ I_F = 1 A - integrated recirculation path eliminates need for discrete flyback diodes
Input Compatibility	TTL - allows direct connection to 5 V logic without level-shifting circuitry
Enable Control	Single active-high EN pin - simplifies system-level power sequencing and fault shutdown
Operating Temperature	–40 °C to +150 °C junction - suitable for under-hood automotive and industrial control environments

Pinout & Package

Package: SO20 (SO16+2+2), surface-mount, 20-pin small-outline package with exposed thermal pad (GND-connected).

Pin/Terminal	Circuit Role	Design Meaning
IN1–IN4	Logic input for Darlington driver 1–4	Non-inverting TTL inputs; each controls one output stage independently
OUT1–OUT4	Open-collector Darlington output	High-side switched outputs tied to load anodes; emitters internally connected to GND
CLAMPA, CLAMPB	Anode of internal freewheeling diodes	CLAMPA connects to OUT1/OUT2; CLAMPB to OUT3/OUT4 - external zener clamping point for inductive energy dissipation
ENABLE	Global output enable	Active-high logic signal enabling/disabling all four drivers simultaneously
VS	Logic supply voltage	5 V nominal (4.5–5.5 V range); powers input buffers and bias networks
GND	Common emitter and substrate reference	Shared emitter node for all Darlington pairs; also serves as thermal and electrical ground plane

Key Features

Feature	Design Value
Integrated freewheeling diodes	Eliminates 4 external diodes, reducing BOM count and PCB area in relay/solenoid driver designs
Parallel channel capability	IN1/IN4 and IN2/IN3 can be paralleled to double current capacity per group (up to 3.6 A) with matched timing
Low V_CE(sat)	1.4 V at 1 A ensures <1.4 W conduction loss per channel, easing thermal design in compact layouts
TTL-compatible inputs	Direct interface with 5 V microcontrollers and FPGA I/O without pull-ups or translators
Thermal enhancement support	Exposed GND pad in SO20 package enables soldering to large copper pour for R_{th j-amb} reduction to ~35 °C/W

Applications

Industrial Solenoid Control

Automotive Relay Interface

Use Scenario: Driving 24 V DC solenoids in programmable logic controller (PLC) output modules.

IC Role / Device Role / Timing Role: High-side switch providing isolated, current-limited actuation with fast turn-off via integrated clamp diodes.

Use Value: Enables reliable 1.8 A per channel switching with <5 µs turn-off delay, minimizing coil hold time and mechanical wear.

Use Scenario: Controlling fuel injector drivers and HVAC actuators in engine control units (ECUs).

IC Role / Device Role / Timing Role: Robust load switch with –40 °C to +150 °C operation and integrated clamping for automotive-grade reliability.

Use Value: Eliminates external flyback protection while meeting ISO 7637-2 pulse immunity requirements through controlled energy recirculation.

Printer Paper Feed Mechanism

Factory Automation Valve Bank

Use Scenario: Sequencing multiple stepper motor phase drivers and paper clutch solenoids in multifunction printers.

IC Role / Device Role / Timing Role: Synchronized quad switch enabling precise timing of mechanical actuation events via shared ENABLE signal.

Use Value: Reduces timing skew between channels to <2 ms on/off delay matching, ensuring consistent paper transport timing.

Use Scenario: Managing pneumatic valve banks in packaging machinery requiring simultaneous multi-valve actuation.

IC Role / Device Role / Timing Role: Parallel-configured Darlington array delivering up to 3.6 A total current across two grouped channels.

Use Value: Supports 100% duty-cycle operation at elevated ambient temperatures using PCB copper heatsinking per ST application note AN410.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad Darlington switch applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ULN2803ADW	8-channel, 500 mA per channel, no integrated clamp diodes (external diodes required), wider SO20 package	Higher channel count but lower per-channel current; suited for low-power LED/relay arrays, not solenoid drivers	Select when needing >4 channels at lower current and cost, with space for external diodes
TB6549FNG	Quad H-bridge driver (bidirectional), 2 A peak per channel, built-in PWM control, no clamp diodes	Supports reversible motor control; lacks dedicated clamp nodes for inductive decay tuning	Choose for bidirectional DC motor control where direction reversal is required, not unidirectional solenoid switching

Compared with ULN2803ADW and TB6549FNG, the L6221CD013TR uniquely combines 1.8 A per channel, integrated clamp diodes with dedicated CLAMP pins for zener-assisted energy recovery, and matched timing across all four channels-making it optimal for high-reliability, high-current unidirectional inductive load switching.

Availability

L6221CD013TR is available at Aetrix Electronics and suitable for industrial PLC output modules, automotive ECU relay interfaces, and factory automation valve banks requiring stable component supply and long-term lifecycle support.

Supply support for L6221CD013TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, MEMS, and microcontroller technologies.

The L6221CD belongs to ST's Power Switching & Drivers product line, engineered specifically for robust, high-voltage industrial and automotive load control with integrated protection and thermal resilience.

FAQ

What is the maximum allowable continuous current per channel at 100°C ambient temperature?

At T_amb = 100°C with standard SO20 mounting on 25 mm² 35 µm copper, the L6221CD013TR supports 1.2 A continuous per channel. This derating follows its R_{th j-amb} = 35 °C/W and T_j(max) = 150°C limit, verified in ST's AN410 thermal guidelines and Figure 26 of the datasheet.

Can CLAMPA and CLAMPB be connected together to a single zener diode?

No-CLAMPA serves OUT1/OUT2 and CLAMPB serves OUT3/OUT4; connecting them violates internal isolation and risks unequal current sharing. ST recommends separate zener clamps per group, as shown in Figure 18, to maintain balanced voltage clamping and avoid thermal runaway.

Is the ENABLE pin electrically compatible with 3.3 V logic systems?

Yes-the ENABLE input has V_ENH (min) = 2.0 V and V_ENL (max) = 0.8 V, making it compatible with 3.3 V CMOS logic. However, VS must remain at 5 V (4.5–5.5 V) to ensure proper internal biasing and output drive strength.

How does paralleling IN1/IN4 affect timing performance?

Paralleling IN1/IN4 (and IN2/IN3) maintains matched turn-on/turn-off delays (<2 ms variation) due to identical logic section characteristics, as confirmed in Figure 19 and Application Note AN222. This preserves synchronous switching critical for multi-coil solenoid banks.

L6221CD013TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: 4 NPN Darlington (Quad)

Current - Collector (Ic) (Max):: 1.2A

Voltage - Collector Emitter Breakdown (Max):: 60V

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SO

L6221CD013TR FAQ

1.How can I place an order for L6221CD013TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L6221CD013TR 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 L6221CD013TR reliable?

The price and inventory of L6221CD013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6221CD013TR is usually 5 days.

3.What payment methods are accepted for L6221CD013TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6221CD013TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6221CD013TR?

L6221CD013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6221CD013TR 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 L6221CD013TR?

For technical support, including L6221CD013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6221CD013TR requirements.

6.How does Aetrix verify that L6221CD013TR is sourced from the original manufacturer or authorized distributors?

All L6221CD013TR 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 L6221CD013TR meets industry standards.

7.What is the process for return or replacement of L6221CD013TR?

All L6221CD013TR units undergo pre-shipment inspection (PSI). If there is an issue with L6221CD013TR, 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 L6221CD013TR part is unused and in its original packaging.

Return procedure for L6221CD013TR:

1.Submit a request within 90 days.

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

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