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STMicroelectronics M5450B7
- Part No.:
- M5450B7
- Manufacturer:
- STMicroelectronics
- Category:
- Display Drivers
- Package:
- 40-DIP (0.600", 15.24mm)
- Datasheet:
-
M5450B7.pdf
- Description:
- IC LED DISPLAY DRIVER 40DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,161
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Product details
Overview
M5450B7 from STMicroelectronics is a 34-output LED display driver IC with 15mA sink capability per output, serial data interface, and analog brightness control via external resistor on pin 19. It operates from 4.75V to 13.2V, supports TTL-compatible inputs, and delivers non-multiplexed direct drive for 4–5-digit alphanumeric displays in industrial instrumentation readouts.
For engineers reviewing the M5450B7 datasheet, M5450B7 pinout, M5450B7 application, or M5450B7 equivalent, key selection factors include its 34-channel constant-current sink architecture, 0.5MHz max clock frequency, PDIP40 package compatibility, and absence of external current-setting resistors per channel.
Technical Context
The M5450B7 integrates a 35-bit static master-slave shift register, 34 output latches (plus enable), and a current generator reference circuit tied to pin 19. Its brightness control uses an internal 400Ω nominal resistor and scales output current linearly with input bias current (0–750µA).
Data loading is synchronous: a leading "1" start bit followed by 35 data bits triggers internal LOAD on the 36th clock edge, while RESET clears shift registers on the clock's falling edge - enabling continuous serial operation without external latch strobes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output count | 34 independent constant-current sink outputs |
| Max sink current | 15mA per output at VB = 4.3V, enabling direct LED segment drive without per-channel resistors |
| Supply voltage | 4.75V to 13.2V - supports wide-range industrial rails including +5V and +12V systems |
| Input clock max | 0.5MHz - limits serial update rate to ≤13.9k segments/sec (35 bits @ 0.5MHz) |
| Brightness control | Analog input on pin 19 (0–750µA) sets reference current; internal 400Ω resistor enables 12–25mA output range |
| Package | PDIP40 - 0.6-inch width, through-hole mounting compatible with legacy industrial PCB layouts |
| Operating temp | –25°C to +85°C - qualified for industrial control environments without derating below 85°C |
Pinout & Package
Package: PDIP40 (Plastic Dual In-line Package, 0.6-inch width, 2.54mm pitch).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–17, 18–34 | Output sink (O1–O34) | 34 open-drain NMOS outputs; each sinks up to 15mA when driven high in data register |
| 19 | Brightness control (IBR) | Analog current input; sets global output current scale via internal 400Ω resistor |
| 20 | Clock input (CLK) | TTL-compatible rising-edge-triggered serial clock; max 0.5MHz |
| 21 | Data input (DIN) | Serial data input; accepts start bit + 35-bit frame for automatic LOAD/RESET |
| 22 | Enable input (EN) | Active-high chip enable; disables all outputs when low (M5450-specific, not present on M5451) |
| 35 | VDD | Positive supply rail (4.75–13.2V); powers logic and output stages |
| 40 | VSS | Ground reference; common return for logic and output current paths |
Key Features
| Feature | Design Value |
|---|---|
| No external current resistors | Integrated current generator eliminates 34 discrete resistors, reducing BOM count and layout area |
| Continuous brightness control | Linear analog scaling via pin 19 allows smooth dimming across full 0–100% intensity range |
| Self-timed load/reset | Internal LOAD and RESET generation on 36th clock edge removes need for external strobe signals |
| TTL-compatible interface | Accepts standard 0.8V/2.2V logic thresholds - interoperable with 5V microcontrollers without level shifters |
Applications
| Microprocessor Displays | Industrial Control Indicators |
|---|---|
Use Scenario: Driving 4-digit 7-segment displays on PLC HMI panels using 8-bit parallel-to-serial shift-out from an 8051 MCU. IC Role / Device Role / Timing Role: Serial-to-parallel LED driver with integrated current regulation; replaces discrete transistor arrays and current-limiting resistors. Use Value: Reduces component count by ≥35 parts per display, eliminates thermal drift in segment brightness, and supports firmware-controlled dimming via DAC-driven pin 19. | Use Scenario: Status indication for relay banks in factory automation cabinets, where 34 LEDs show ON/OFF states of individual contactors. IC Role / Device Role / Timing Role: High-reliability sink driver with 15mA per channel - ensures full brightness even under 40°C ambient and 12V supply variation. Use Value: Enables direct connection to 12V relay coils or optocouplers without external drivers; maintains consistent LED luminance across 34 channels within ±20% matching. |
| Relay Driver | Instrumentation Readouts |
Use Scenario: Driving ULN2003A-input relays in HVAC control modules, where M5450B7 provides logic-level sinking to activate relay bases. IC Role / Device Role / Timing Role: Digital output expander with current-regulated sink outputs - interfaces microcontroller GPIO to higher-power relay control circuits. Use Value: Eliminates need for discrete base resistors on 34 NPN transistors; simplifies PCB routing and improves EMI immunity via reduced trace lengths. | Use Scenario: Analog meter replacement in multimeters and oscilloscope front panels, displaying measured values on multiplexed 5-digit vacuum fluorescent displays. IC Role / Device Role / Timing Role: Non-multiplexed segment driver delivering stable DC current to VF display anodes - avoids flicker and ghosting in precision instruments. Use Value: Ensures zero-flicker digit rendering at full brightness; supports calibration via pin 19 current trim to match photometric response across units. |
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 driver with SPI interface and on-chip decoding; requires external current resistors per digit | Targets multiplexed LED matrices; lacks direct 34-output non-multiplexed capability | Select for SPI-based systems needing built-in BCD decode and scan control - not for direct 34-segment static drive |
| TPIC6B595 | 8-bit shift-register output driver with 150mA sink per channel; no integrated current regulation or brightness control | Designed for high-current loads (relays, solenoids); no analog dimming or segment-matching features | Select when driving >15mA loads or requiring higher voltage tolerance (up to 50V); adds external current limiting per channel |
Compared with MAX7219 and TPIC6B595, the M5450B7 uniquely delivers 34-channel matched constant-current sinking with analog brightness scaling in a single PDIP40 package - making it optimal for static alphanumeric displays where per-segment uniformity and minimal external components are critical.
Availability
M5450B7 is available at Aetrix Electronics and suitable for industrial control indicators, instrumentation readouts, and microprocessor display subsystems requiring stable component supply and long-lifecycle support.
Supply support for M5450B7 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, microcontrollers, and analog/mixed-signal ICs for industrial and automotive markets.
The M5450B7 belongs to ST's legacy LED display driver product line, designed specifically for cost-sensitive, high-reliability industrial instrumentation and control panel applications requiring direct-drive static segment control.
FAQ
What is the maximum number of LED segments the M5450B7 can drive simultaneously?
The M5450B7 can drive all 34 outputs simultaneously at up to 15mA each. Thermal limits require that total power dissipation remain ≤560mW at +85°C ambient - achievable with ≤20 segments active at 15mA when VDD = 13.2V, or up to 34 segments at lower currents or cooler temperatures.
Does the M5450B7 require external current-setting resistors per output?
No. The M5450B7 uses an internal current generator referenced to pin 19. A single external resistor sets global brightness, eliminating 34 discrete resistors. Output current scales linearly with pin 19 bias current (0–750µA), with typical 15mA output at 750µA input.
How does the serial data protocol work without a separate load signal?
The protocol uses a 36-bit frame: one leading "1" start bit followed by 35 data bits. On the 36th clock edge, the device generates an internal LOAD pulse to transfer shift register contents to output latches, and a RESET pulse on the falling edge to clear the shift register - removing need for external strobes.
Can the M5450B7 drive common-anode or common-cathode LED displays?
The M5450B7 drives only common-anode LED displays. Its 34 outputs are NMOS open-drain sinks - they connect LED cathodes to ground while anodes are tied to VDD or a higher voltage rail. It cannot source current, so common-cathode configurations are incompatible.
M5450B7 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
M5450B7 FAQ
1.How can I place an order for M5450B7 through Aetrix?
Please submit a Request for Quotation (RFQ) for M5450B7 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 M5450B7 reliable?
The price and inventory of M5450B7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M5450B7 is usually 5 days.
3.What payment methods are accepted for M5450B7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M5450B7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M5450B7?
M5450B7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M5450B7 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 M5450B7?
For technical support, including M5450B7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M5450B7 requirements.
6.How does Aetrix verify that M5450B7 is sourced from the original manufacturer or authorized distributors?
All M5450B7 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 M5450B7 meets industry standards.
7.What is the process for return or replacement of M5450B7?
All M5450B7 units undergo pre-shipment inspection (PSI). If there is an issue with M5450B7, 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 M5450B7 part is unused and in its original packaging.
Return procedure for M5450B7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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