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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Supply Controllers, Monitors

Texas Instruments UC2544N

Name: UC2544N
Brand: Texas Instruments
SKU: UC2544N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: UC2544N

Manufacturer:: Texas Instruments

Category:: Power Supply Controllers, Monitors

Package:: 18-DIP (0.300", 7.62mm)

Datasheet:: UC2544N.pdf

Description:: IC SUPERVISOR 2.5V 18DIP

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Product details

Overview

UC2544N from Texas Instruments is a monolithic power supply supervisory IC integrating over-voltage (O.V.), under-voltage (U.V.), and current-limit (C.L.) sensing circuits with open-collector indicator outputs, an SCR crowbar driver (300 mA peak), programmable time delays, and a 2.5 V ±1% internal reference. It operates from 4.7 V to 40 V input, supports remote activation and external reset, and is used in regulated DC power supplies for fault detection and shutdown control.

For engineers reviewing the UC2544N datasheet, UC2544N pinout, UC2544N application, or UC2544N equivalent, key selection criteria include its dual-threshold voltage monitoring capability, independent comparator inputs enabling sub-2.5 V U.V. sensing via reference division, SCR trigger propagation delay (500 ns), and PDIP-18 package compatibility with legacy industrial power designs.

Technical Context

The UC2544N implements three independent analog monitoring channels: an over-voltage comparator with latch/reset capability and SCR trigger output; an under-voltage comparator with externally programmable delay; and a current-sense amplifier configurable as linear amplifier or high-gain comparator with offset adjustment. All comparators share the same 2.5 V reference and accept differential inputs.

Its architecture supports flexible fault coordination: O.V., U.V., and C.L. outputs are open-collector and wire-or'able; the SCR trigger is directly driven by O.V. but can be optionally activated by any indicator output or external signal; uncommitted comparator inputs allow custom threshold setting below 2.5 V using resistor dividers from VREF.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	4.7 V to 40 V - powers directly from monitored output or auxiliary bias rail without external regulator
Reference Voltage	2.50 V ±1% - eliminates need for external trimming potentiometer in threshold-setting networks
SCR Trigger Current	−300 mA peak - drives standard SCRs without external buffer stage in crowbar protection circuits
O.V./U.V. Input Threshold	2.50 V ±20 mV - enables precise trip points when referenced to internal VREF via resistive dividers
Propagation Delay (O.V.)	500 ns - ensures fast response to over-voltage transients before downstream damage occurs
Operating Temperature	−40°C to +85°C - qualified for commercial/industrial ambient environments per UC25xx series specification
Current Sense Bandwidth	5 MHz - supports high-speed current limiting in switching power supplies with fast load steps

Pinout & Package

UC2544N is supplied in an 18-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and standard through-hole mounting footprint.

Pin/Terminal	Circuit Role	Design Meaning
1	VIN	Main supply input - powers internal circuitry and provides bias for SCR driver stage
2	VREF	2.5 V reference output - used as precision voltage source for external resistor-divider threshold networks
3	GND	Analog ground reference - common return for all internal comparators and reference generator
4	C.L. Output	Current limit comparator output - open-collector, sinks up to 10 mA, wire-or'able with other indicators
5	Offset/Comp	Current sense amplifier offset adjustment - adds fixed threshold via external resistor to enable voltage monitoring mode
6	C.L. N.I. Input	Current sense non-inverting input - accepts positive-side current shunt voltage or external signal
7	C.L. INV. Input	Current sense inverting input - accepts negative-side shunt voltage or feedback for amplifier configuration
8	U.V. Indicate	Under-voltage detector output - open-collector, active-low, indicates U.V. fault condition
9	U.V. Delay	U.V. timing capacitor connection - sets delay before U.V. indication asserts after threshold breach
10	SCR Trigger	SCR gate drive output - delivers −300 mA pulse to trigger external crowbar SCR
11	Remote Activate	External fault initiation input - pulls low to force immediate SCR trigger independent of O.V./U.V./C.L.
12	Reset	External reset input - pulls low to clear O.V. latch and disable SCR trigger until next fault
13	O.V. Indicate	Over-voltage detector output - open-collector, active-low, indicates O.V. fault and controls latch state
14	O.V. Delay	O.V. timing capacitor connection - sets minimum fault duration before O.V. indication asserts
15	O.V. N.I. Input	O.V. non-inverting input - connected to VREF-divided network for precise over-voltage threshold
16	O.V. INV. Input	O.V. inverting input - accepts monitored voltage directly or via divider for differential O.V. comparison
17	U.V. N.I. Input	U.V. non-inverting input - accepts monitored voltage directly for standard U.V. detection
18	U.V. INV. Input	U.V. inverting input - connected to VREF for fixed 2.5 V threshold or adjustable via divider

Key Features

Feature	Design Value
Programmable O.V./U.V. time delays	Capacitor-controlled delays prevent nuisance tripping during startup or transient line disturbances
Uncommitted comparator inputs	Enables monitoring of voltages <2.5 V using VREF as reference, extending applicability beyond fixed thresholds
SCR crowbar drive (300 mA)	Directly triggers external SCR for fast, high-energy short-circuit protection without gate driver IC
Independent current sense amplifier	Configurable as linear amplifier or comparator with offset adjustment - supports both current limiting and auxiliary voltage monitoring
Internal 1% accurate 2.5 V reference	Stable reference eliminates external precision voltage source, reducing BOM count and layout area

Applications

DC Power Supply Protection	Industrial Motor Drive PSU
Use Scenario: Monitoring +12 V and +5 V rails in a multi-output switch-mode power supply for telecom equipment. IC Role / Device Role / Timing Role: UC2544N continuously compares each rail against VREF-derived thresholds and triggers SCR crowbar on over-voltage exceeding 105% nominal. Use Value: Prevents catastrophic failure of downstream FPGAs and interface ICs by initiating sub-millisecond shutdown upon O.V. detection.	Use Scenario: Supervising the main DC bus voltage (48 V) and gate driver bias (15 V) in an IGBT-based servo drive power stage. IC Role / Device Role / Timing Role: UC2544N uses O.V. and U.V. inputs to detect bus overvoltage (>55 V) and undervoltage (<40 V), asserting separate indicator outputs for PLC interlock and disabling gate drivers. Use Value: Enables safe, coordinated shutdown of motor control logic and power stage before IGBT destruction due to overvoltage stress or loss of gate bias.
Programmable Logic Controller PSU	Test Equipment Power Module
Use Scenario: Ensuring stable operation of a 24 V isolated power module supplying CPU, I/O, and communication interfaces in an industrial PLC. IC Role / Device Role / Timing Role: UC2544N monitors 24 V output with 100 ms U.V. delay and 10 ms O.V. delay, while its current sense channel detects output overload >5 A via shunt resistor. Use Value: Provides triple-fault coverage (O.V., U.V., overcurrent) with independent outputs, allowing modular fault reporting to controller firmware without software polling.	Use Scenario: Protecting a benchtop programmable DC power supply's output stage during automated test sequences with variable loads. IC Role / Device Role / Timing Role: UC2544N's remote activate input receives TTL-level fault signals from DUT interface, forcing immediate SCR crowbar regardless of sensed voltage levels. Use Value: Adds fail-safe hardware override path that bypasses analog sensing latency, critical for protecting DUTs during rapid fault escalation in ATE systems.

DC Power Supply Protection

Industrial Motor Drive PSU

Use Scenario: Monitoring +12 V and +5 V rails in a multi-output switch-mode power supply for telecom equipment.

IC Role / Device Role / Timing Role: UC2544N continuously compares each rail against VREF-derived thresholds and triggers SCR crowbar on over-voltage exceeding 105% nominal.

Use Value: Prevents catastrophic failure of downstream FPGAs and interface ICs by initiating sub-millisecond shutdown upon O.V. detection.

Use Scenario: Supervising the main DC bus voltage (48 V) and gate driver bias (15 V) in an IGBT-based servo drive power stage.

IC Role / Device Role / Timing Role: UC2544N uses O.V. and U.V. inputs to detect bus overvoltage (>55 V) and undervoltage (<40 V), asserting separate indicator outputs for PLC interlock and disabling gate drivers.

Use Value: Enables safe, coordinated shutdown of motor control logic and power stage before IGBT destruction due to overvoltage stress or loss of gate bias.

Programmable Logic Controller PSU

Test Equipment Power Module

Use Scenario: Ensuring stable operation of a 24 V isolated power module supplying CPU, I/O, and communication interfaces in an industrial PLC.

IC Role / Device Role / Timing Role: UC2544N monitors 24 V output with 100 ms U.V. delay and 10 ms O.V. delay, while its current sense channel detects output overload >5 A via shunt resistor.

Use Value: Provides triple-fault coverage (O.V., U.V., overcurrent) with independent outputs, allowing modular fault reporting to controller firmware without software polling.

Use Scenario: Protecting a benchtop programmable DC power supply's output stage during automated test sequences with variable loads.

IC Role / Device Role / Timing Role: UC2544N's remote activate input receives TTL-level fault signals from DUT interface, forcing immediate SCR crowbar regardless of sensed voltage levels.

Use Value: Adds fail-safe hardware override path that bypasses analog sensing latency, critical for protecting DUTs during rapid fault escalation in ATE systems.

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply supervisory applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
UC3544N	0°C to +70°C operating range; lower temperature grade than UC2544N's −40°C to +85°C	Suitable for commercial-grade lab equipment but not industrial enclosures with wide ambient swings	Select UC3544N only if ambient temperature stays within 0–70°C and cost sensitivity outweighs extended thermal margin
TL7705ACD	Single-supply voltage supervisor (5 V only); no current sense or SCR drive; fixed 4.65 V threshold	Lacks O.V./U.V. programmability, crowbar capability, and current monitoring - limited to basic 5 V rail monitoring	Choose TL7705ACD only for simple 5 V reset generation where UC2544N's full feature set is unnecessary

Compared with UC3544N and TL7705ACD, UC2544N uniquely combines wide-input-voltage supervision, three independent fault channels, and integrated SCR drive in a single PDIP-18 package - making it irreplaceable for robust, multi-rail industrial power protection where thermal resilience and hardware-initiated shutdown are mandatory.

Availability

UC2544N is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controller power supplies, and test equipment power modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for UC2544N 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and digital signal processing technologies since 1930.

The UC2544N belongs to TI's UCx54x family of monolithic power supply supervisory circuits, engineered specifically for high-reliability industrial and telecom power systems requiring coordinated over-voltage, under-voltage, and overcurrent fault detection with hardware-level crowbar protection.

FAQ

What is the maximum input voltage rating for the UC2544N?

The UC2544N has an absolute maximum input supply voltage (VIN) rating of 40 V. This allows direct connection to common industrial DC rails such as 24 V, 36 V, and 48 V systems without external regulation. Exceeding 40 V risks permanent damage to internal circuitry, including the reference generator and comparator input stages. The device is specified to operate reliably from 4.7 V to 40 V across its full −40°C to +85°C temperature range.

Can the UC2544N monitor voltages below 2.5 V?

Yes, the UC2544N can monitor voltages below 2.5 V using its uncommitted comparator inputs. By connecting a resistor divider from VREF (Pin 2) to ground and feeding the divided voltage to either O.V. or U.V. inputs, users establish custom thresholds down to millivolt levels. For example, a 2:1 divider yields 1.25 V threshold; the internal 2.5 V reference's ±1% accuracy ensures corresponding threshold tolerance. This capability is explicitly documented for UC2544-series devices in the TI SLUS188A datasheet.

Does the UC2544N require external components to function as a basic over-voltage protector?

Yes, the UC2544N requires external components for basic over-voltage protection: a timing capacitor on Pin 14 (O.V. Delay) to set fault-hold duration, a pull-up resistor on Pin 13 (O.V. Indicate) for logic-level interfacing, and an external SCR with gate current-limiting resistor. The SCR gate resistor (RG) must be selected per the formula RG > (VIN − 0.2 V)/0.3 A to limit power dissipation, as specified in the application information section of the UC2544N datasheet.

What is the purpose of the Offset/Comp pin (Pin 5) on the UC2544N?

The Offset/Comp pin (Pin 5) on the UC2544N adjusts the input offset voltage of the current sense amplifier. Connecting a resistor from this pin to ground introduces a fixed threshold voltage (e.g., 10 mV with 10 kΩ), enabling the amplifier to function as a precision voltage monitor instead of a zero-threshold current sensor. This allows reuse of the C.L. channel for auxiliary voltage supervision - a documented design technique in the UC2544N application notes for expanding fault coverage without adding discrete comparators.

Is the UC2544N pin-compatible with other members of the UCx54x family?

No, the UC2544N is not fully pin-compatible with UC1544 or UC3544 variants due to differing pin counts and assignments. UC2544N uses an 18-pin PDIP package with dedicated U.V. N.I./INV. inputs (Pins 17–18), whereas UC2543/UC3543 use 16-pin packages lacking those terminals. While functional blocks align across the family, physical pin mapping differs - confirmed by TI's connection diagrams showing distinct top-view layouts for 16-pin vs. 18-pin versions. Always consult the specific device's package drawing before PCB layout.

UC2544N Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 18-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Applications:: Power Supply, Supervisor

Voltage - Input:: 4.5V ~ 40V

Voltage - Supply:: -

Current - Supply:: 7 mA

Operating Temperature:: -25°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 18-PDIP

UC2544N FAQ

1.How can I place an order for UC2544N through Aetrix?

Please submit a Request for Quotation (RFQ) for UC2544N 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 UC2544N reliable?

The price and inventory of UC2544N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2544N is usually 5 days.

3.What payment methods are accepted for UC2544N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2544N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for UC2544N?

UC2544N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your UC2544N 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 UC2544N?

For technical support, including UC2544N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2544N requirements.

6.How does Aetrix verify that UC2544N is sourced from the original manufacturer or authorized distributors?

All UC2544N 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 UC2544N meets industry standards.

7.What is the process for return or replacement of UC2544N?

All UC2544N units undergo pre-shipment inspection (PSI). If there is an issue with UC2544N, 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 UC2544N part is unused and in its original packaging.

Return procedure for UC2544N:

1.Submit a request within 90 days.

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

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