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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Display Drivers

STMicroelectronics M5451Q

Name: M5451Q
Brand: STMicroelectronics
SKU: M5451Q
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M5451Q

Manufacturer:: STMicroelectronics

Category:: Display Drivers

Package:: 44-LCC (J-Lead)

Datasheet:: M5451Q.pdf

Description:: IC LED DISPL DRVR 4/5 DGT 44PLCC

Quantity:: RFQ Add To RFQ list

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Inventory:4,171

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Product details

Overview

M5451Q from STMicroelectronics is a 35-channel LED display driver IC with integrated current-sink outputs (15 mA typical per channel), serial data interface, and analog brightness control via external resistor on pin 19. It operates from 4.75 V to 13.2 V, supports non-multiplexed direct drive of alphanumeric displays, and is packaged in a 44-pin PLCC. Used in industrial instrumentation readouts and microprocessor-based display systems.

For engineers reviewing the M5451Q datasheet, M5451Q pinout, M5451Q application, or M5451Q equivalent, key selection criteria include its 35-bit serial shift register + latch architecture, internal 400 Ω brightness reference resistor, ±20% output current matching, and compatibility with TTL-level clock/data inputs at up to 0.5 MHz.

Technical Context

The M5451Q implements a static master-slave 35-bit shift register followed by parallel latches, enabling non-multiplexed LED segment control. Data loading occurs synchronously on the 36th clock edge after a leading "1" start bit, eliminating need for separate LOAD signals.

Brightness is set by an external variable resistor connected to pin 19 (VB), which sources 0–750 µA into an internal current mirror; output sink current scales linearly (e.g., 750 µA → 15 mA/channel). The device includes internal power-on reset and requires a 1 nF capacitor on pin 19 to suppress oscillation.

Key Specifications

Parameter	Value and Actual Design Meaning
Output channels	35 independent current-sink outputs for direct LED segment drive
Output current	15 mA typical per channel at VB = 750 µA; max 40 mA absolute rating
Supply voltage	4.75 V to 13.2 V - supports wide-range industrial rails without regulation
Input clock frequency	DC to 0.5 MHz - enables low-speed microcontroller interfacing without timing constraints
Output current matching	±20% variation - ensures uniform LED brightness across all 35 segments
Brightness control	Analog via pin 19 (VB); 0–750 µA input sets full-scale output current
Logic compatibility	TTL-level inputs (VIH ≥ 2.2 V @ VDD ≤ 5.25 V) - interoperable with legacy 5 V MCUs

Pinout & Package

Package: 44-pin Plastic Leaded Chip Carrier (PLCC44), 17.4 mm × 16.51 mm footprint, 3.65 mm height, JEDEC MS-026 compliant.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, ..., 17, 18, 20–34	Output bit (sink)	35 dedicated current-sink outputs - pins 1–17, 18, 20–34; pin 19 is brightness control, not output
19	Brightness control input	Analog current input (0–750 µA); sets global output current scaling via internal mirror
21, 22	Data In / Clock In	Serial interface: rising-edge-triggered clock and LSB-first data with start bit
40	VDD	Main supply rail (4.75–13.2 V); powers logic and output drivers
29	VSS	Ground reference for logic and output sinks

Key Features

Feature	Design Value
No external current-setting resistors	Internal 400 Ω reference resistor eliminates per-output Rset components and layout complexity
Continuous analog brightness control	Precision current mirror allows smooth dimming without PWM or digital register writes
36-bit serial protocol with auto-load	Leading "1" + 35 data bits triggers automatic latch update on 36th clock - no separate LOAD signal required
Power-on reset & static shift register	Guarantees known initial state at startup; master-slave design enables continuous streaming without gaps

Applications

Industrial Instrumentation Readouts

Microprocessor Display Systems

Use Scenario: Driving 5-digit alphanumeric LED displays in panel meters and process controllers.

IC Role / Device Role / Timing Role: Direct segment driver with non-multiplexed output - eliminates external multiplexing logic and timing firmware overhead.

Use Value: Reduces BOM count by removing 35 discrete current-limiting resistors and simplifies PCB routing with single serial interface.

Use Scenario: Interface between 8-bit microcontrollers (e.g., 8051 derivatives) and multi-digit LED displays in embedded HMI.

IC Role / Device Role / Timing Role: Serial-to-parallel converter with integrated current sinks - accepts standard shift-out instructions without GPIO expansion.

Use Value: Enables full 35-segment control using only two MCU I/O pins (DATA, CLOCK), freeing GPIO for sensors or communication.

Relay Driver Interfaces

Electronically Tuned Radio/TV Frontends

Use Scenario: Driving LED status indicators for relay banks in PLC I/O modules.

IC Role / Device Role / Timing Role: High-voltage-tolerant sink driver (VO(off) = 13.2 V) - directly interfaces with relay coil return paths referenced to VDD.

Use Value: Eliminates need for optocouplers or level-shifting transistors when relays share common VDD rail.

Use Scenario: Segment control in FM/AM radio tuning displays with station identification and signal strength bars.

IC Role / Device Role / Timing Role: Dedicated display controller synchronized to tuning controller's serial bus - handles display updates independently of RF processing.

Use Value: Offloads display management from main controller, ensuring flicker-free updates during PLL frequency sweeps.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED display driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX7219	8-digit, 64-segment scan driver with SPI interface and on-chip decoding; requires external current-setting resistor	Designed for multiplexed 7-segment displays; lacks direct 35-bit non-multiplexed output capability	Select for space-constrained designs needing digit-level control and built-in BCD decode
TLC59282	16-channel constant-current sink driver with PWM brightness control and 30 MHz SPI; no analog brightness input	Requires external shift register or MCU with high-speed SPI; no native 35-bit serial protocol	Select when precise per-channel PWM dimming and higher channel density per package are required

Compared with MAX7219 and TLC59282, the M5451Q uniquely delivers 35-channel direct drive with analog brightness scaling and zero-external-resistor operation - ideal for fixed-format alphanumeric displays where simplicity and minimal component count outweigh programmability needs.

Availability

M5451Q is available at Aetrix Electronics and suitable for industrial instrumentation readouts, microprocessor display systems, and relay driver interfaces requiring stable component supply and long-lifecycle support.

Supply support for M5451Q 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 automotive, industrial, and power management ICs with broad manufacturing and quality certifications.

The M5451Q belongs to ST's legacy LED display driver product line, designed specifically for cost-sensitive, high-reliability alphanumeric display applications in industrial control and consumer electronics front panels.

FAQ

What is the maximum number of LEDs the M5451Q can drive simultaneously?

The M5451Q can drive all 35 outputs concurrently at up to 15 mA each. Total power dissipation must remain within limits: at Tamb = 85°C, maximum total power is 560 mW. With VO = 1 V per output and 35 segments active, total power is ~0.525 W - within safe operating area per Figure 7. Thermal derating applies above 85°C ambient.

Does the M5451Q require an external load signal for data latching?

No. The M5451Q uses a 36-bit serial frame (1 start bit + 35 data bits) where the 36th clock edge automatically generates an internal LOAD pulse. This eliminates need for a separate LOAD or strobe signal - simplifying interface to microcontrollers with basic shift-out capability.

Can the M5451Q drive LEDs with forward voltages above 3 V?

Yes. The off-state output voltage rating is 13.2 V, and VO(max) is limited only by VDD. When driving high-VF LEDs (e.g., white or blue), ensure VDD exceeds total LED VF plus margin. Output saturation voltage is ~0.5 V at 15 mA, so usable headroom is VDD − 0.5 V per segment.

Is a capacitor required on the brightness control pin (pin 19)?

Yes. A 1 nF capacitor must be connected between pin 19 and VSS to prevent oscillation in the internal current mirror. Omission may cause unstable output current and visible LED flicker. The capacitor stabilizes the feedback loop and is specified in the functional description on page 3 of the datasheet.

M5451Q Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 44-LCC (J-Lead)

Packaging:: Tube

Product Status:: Obsolete

Display Type:: LED

Configuration:: Alphanumeric or Dot Matrix

Interface:: Serial

Digits or Characters:: 4 or 5 Digits

Current - Supply:: 7 mA

Voltage - Supply:: 4.75V ~ 13.2V

Operating Temperature:: -25°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 44-PLCC (16.58x16.58)

M5451Q FAQ

1.How can I place an order for M5451Q through Aetrix?

Please submit a Request for Quotation (RFQ) for M5451Q 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 M5451Q reliable?

The price and inventory of M5451Q are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M5451Q is usually 5 days.

3.What payment methods are accepted for M5451Q?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M5451Q transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M5451Q?

M5451Q orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M5451Q 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 M5451Q?

For technical support, including M5451Q datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M5451Q requirements.

6.How does Aetrix verify that M5451Q is sourced from the original manufacturer or authorized distributors?

All M5451Q 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 M5451Q meets industry standards.

7.What is the process for return or replacement of M5451Q?

All M5451Q units undergo pre-shipment inspection (PSI). If there is an issue with M5451Q, 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 M5451Q part is unused and in its original packaging.

Return procedure for M5451Q:

1.Submit a request within 90 days.

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

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