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

STMicroelectronics M5451B7

Name: M5451B7
Brand: STMicroelectronics
SKU: M5451B7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M5451B7

Manufacturer:: STMicroelectronics

Category:: Display Drivers

Package:: 40-DIP (0.600", 15.24mm)

Datasheet:: M5451B7.pdf

Description:: IC LED DISPLAY DRIVER 40DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

M5451B7 from STMicroelectronics is a 35-channel LED display driver IC with 15 mA sink current per output, 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 housed in a 40-pin PDIP package rated for –25 °C to +85 °C. Used in microprocessor-based instrumentation readouts and industrial control indicators.

For engineers reviewing the M5451B7 datasheet, M5451B7 pinout, M5451B7 application, or M5451B7 equivalent, key selection considerations include its fixed 35-output configuration (vs. M5450's 34 outputs + enable), absence of DATA ENABLE pin, brightness control current range (0–750 µA), and thermal limits under segment load conditions.

Technical Context

The M5451B7 integrates a 35-bit static master-slave shift register, 35 output latches, and 35 current-sink drivers with internal 400 Ω reference resistor. Data loading occurs synchronously on the 36th clock edge after a leading "1" start bit, eliminating need for separate LOAD signal.

Output current is set by external resistor on pin 19 (VB = 3–4.3 V at 750 µA), delivering nominal 15 mA per segment at VO = 1 V. Maximum sink current per output is 40 mA, with ±20% matching across outputs and 0.5 MHz max clock frequency.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Count	35 independent current-sink outputs for direct LED segment drive
Sink Current (Typ)	15 mA per output at VO = 1 V, set by external brightness resistor
Supply Voltage	4.75 V to 13.2 V - supports wide-range industrial power rails
Max Clock Frequency	0.5 MHz - defines maximum serial update rate for full 35-bit frame
Output Matching	±20% variation - ensures consistent brightness across all 35 segments
Junction Temp Limit	150 °C - constrains thermal design when driving >20 segments simultaneously
Package	PDIP40 - through-hole mounting compatible with legacy industrial PCB assembly

Pinout & Package

Package: 40-pin Plastic Dual In-line Package (PDIP40), 0.6 inch width, lead pitch 2.54 mm, operating temperature range –25 °C to +85 °C.

Pin/Terminal	Circuit Role	Design Meaning
1–17, 18–34	Output Bit 1 to 34	Current-sink drivers for LED segments; logic high at input turns on corresponding LED
35	Output Bit 35	Dedicated 35th sink output - distinguishes M5451 from M5450 (which uses this pin as DATA ENABLE)
19	Brightness Control	Analog input accepting 0–750 µA to set reference current; requires 1 nF capacitor to suppress oscillation
21	Data In	Serial input accepting start bit + 35 data bits; TTL-compatible, no external pull-up required
22	Clock In	Positive-edge-triggered serial clock; max 0.5 MHz; generates internal LOAD/RESET signals
40, 20	VDD	Main supply input (4.75–13.2 V); powers logic and output stages
23	VSS	Ground reference for logic and output sinks

Key Features

Feature	Design Value
No external current-setting resistors	Internal 400 Ω reference resistor enables precise per-output current control via single brightness pin
Start-bit synchronized serial protocol	Leading "1" + 35 data bits eliminates need for separate LOAD signal; simplifies MCU interface
Non-multiplexed direct drive	35 latched outputs provide static segment illumination - avoids flicker and timing-critical refresh
Thermal-aware operation	Junction temperature calculation formula provided (Tj = [(VOUT × ILED × N) + (VDD × 7 mA)] × 124°C/W + Tamb)
Power-on reset	Internal POR clears all registers and latches at startup - ensures deterministic initial state

Applications

Industrial Panel Meters

Test Equipment Readouts

Use Scenario: 5-digit LED numeric display on benchtop multimeter front panel.

IC Role / Device Role / Timing Role: Direct-sink driver for all segments; receives serial updates from MCU every 200 ms.

Use Value: Eliminates need for discrete transistors or external current sources - reduces BOM count by 35 components.

Use Scenario: Alphanumeric status display on oscilloscope control module.

IC Role / Device Role / Timing Role: Static segment driver handling uppercase letters and symbols; updated only on mode change.

Use Value: Stable brightness across all characters due to matched output current (±20%), critical for lab-grade readability.

Appliance Control Panels

Legacy Industrial HMIs

Use Scenario: Microwave oven timer and function display with 4-digit numeric + symbol indicators.

IC Role / Device Role / Timing Role: Segment driver interfaced to 8-bit parallel-to-serial shift register; driven at ≤100 kHz.

Use Value: Wide 4.75–13.2 V supply range accommodates unregulated 12 V rail common in white-goods power supplies.

Use Scenario: PLC-mounted status indicator with 34-segment bar graph and 1 spare segment.

IC Role / Device Role / Timing Role: Fixed-function LED driver replacing aging discrete transistor arrays in field-replaceable modules.

Use Value: PDIP40 package enables hand-soldering and socket replacement in maintenance scenarios.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
M5450B7	34 outputs + dedicated DATA ENABLE pin instead of Output Bit 35; identical brightness control and pinout except pin 35 function	Used where system requires external gating of display updates rather than full 35-segment drive	Select M5450B7 only if enable-controlled update timing is required; not drop-in compatible due to pin 35 functional difference
TLC59282	16-channel constant-current sink driver with SPI interface, 12-bit PWM brightness control, and thermal shutdown	Requires microcontroller with SPI peripheral; supports grayscale, not binary on/off	Choose TLC59282 for modern designs needing programmable dimming and fault protection - not suitable for legacy M5451B7 drop-in replacement

Compared with M5450B7, the M5451B7 provides one additional dedicated output instead of an enable function - critical for full 35-segment displays. Versus TLC59282, it offers simpler TTL-level serial protocol and no firmware dependency, but lacks PWM dimming and thermal safety features.

Availability

M5451B7 is available at Aetrix Electronics and suitable for industrial panel meters, test equipment readouts, appliance control panels, and legacy industrial HMIs requiring stable component supply and long-lifecycle support.

Supply support for M5451B7 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 infrastructure.

The M5451B7 belongs to ST's legacy LED display driver product line, designed specifically for cost-sensitive, high-reliability alphanumeric display systems in industrial instrumentation and consumer appliances.

FAQ

What is the maximum number of LED segments the M5451B7 can drive simultaneously without exceeding thermal limits?

The M5451B7 can safely drive up to 34 segments continuously at 15 mA each when ambient temperature is ≤40 °C and VDD = 12 V, based on its 1 W total package power dissipation limit at 25 °C and thermal coefficient of 124 °C/W. Driving all 35 segments requires derating to ≤12 mA per segment above 40 °C ambient.

Does the M5451B7 require an external pull-up resistor on the DATA IN pin?

No. The M5451B7 DATA IN pin (pin 21) has TTL-compatible input thresholds and internal biasing; it accepts clean CMOS or TTL logic levels directly from microcontrollers without external pull-up or pull-down resistors. A series 100 Ω resistor is recommended for noise suppression in noisy industrial environments.

Can the brightness control pin (pin 19) be driven with a DAC voltage instead of a resistor?

Yes - pin 19 accepts a DC voltage between 3 V and 4.3 V (at 750 µA), so a precision DAC output within that range can replace the variable resistor for digitally controlled brightness. However, the 1 nF capacitor must still be placed from pin 19 to VSS to prevent oscillation, as specified in the datasheet.

Is the M5451B7 pin-compatible with newer ST display drivers like the STP16CP05?

No. The M5451B7 uses a proprietary 36-bit start-bit serial protocol and 40-pin PDIP layout, while the STP16CP05 is a 16-channel constant-current driver in TSSOP24 with SPI interface and different pin functions. They are not pin- or protocol-compatible; migration requires PCB redesign and firmware changes.

M5451B7 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 40-DIP (0.600", 15.24mm)

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:: Through Hole

Supplier Device Package:: 40-PDIP

M5451B7 FAQ

1.How can I place an order for M5451B7 through Aetrix?

Please submit a Request for Quotation (RFQ) for M5451B7 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 M5451B7 reliable?

The price and inventory of M5451B7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M5451B7 is usually 5 days.

3.What payment methods are accepted for M5451B7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M5451B7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M5451B7?

M5451B7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M5451B7 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 M5451B7?

For technical support, including M5451B7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M5451B7 requirements.

6.How does Aetrix verify that M5451B7 is sourced from the original manufacturer or authorized distributors?

All M5451B7 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 M5451B7 meets industry standards.

7.What is the process for return or replacement of M5451B7?

All M5451B7 units undergo pre-shipment inspection (PSI). If there is an issue with M5451B7, 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 M5451B7 part is unused and in its original packaging.

Return procedure for M5451B7:

1.Submit a request within 90 days.

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

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