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STMicroelectronics L78M05CDT-1
- Part No.:
- L78M05CDT-1
- Manufacturer:
- STMicroelectronics
- Package:
- TO-251-3 Short Leads, IPAK, TO-251AA
- Datasheet:
-
L78M05CDT-1.pdf
- Description:
- IC REG LINEAR 5V 500MA IPAK
- Quantity:
- Payment:
- Shipping:
Inventory:3,361
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Product details
Overview
L78M05CDT-1 from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 5 V ±4 % at up to 0.5 A output current in TO-220FP package. It integrates thermal overload protection, short-circuit current limiting, and safe operating area (SOA) compensation for robust local on-card regulation in industrial power supplies, embedded controllers, and sensor interface circuits.
For engineers reviewing the L78M05CDT-1 datasheet, L78M05CDT-1 pinout, L78M05CDT-1 application, or L78M05CDT-1 equivalent, key selection criteria include guaranteed 5 V output tolerance (±4 %), 2 V dropout voltage at 25 °C, junction temperature range of 0 to 150 °C, and thermal resistance junction-to-case of 5 °C/W - all critical for thermally constrained 5 V rail designs.
Technical Context
The L78M05CDT-1 implements a monolithic NPN pass transistor with internal current limiting, thermal shutdown, and SOA protection. Its architecture relies on a bandgap reference and error amplifier to maintain regulated output under varying load and line conditions without external compensation.
It operates as a fixed-output linear regulator requiring only input and output bypass capacitors (0.33 µF and 0.1 µF respectively) for stability. No external feedback network is needed, and it supports adjustable configurations via external resistors or transistors per application circuits in DS0425.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5 V ±4 % (C-grade tolerance) - ensures compatibility with 5 V logic and analog subsystems requiring relaxed accuracy |
| Max Output Current | 500 mA - sufficient for powering microcontrollers, sensors, and peripheral ICs in compact systems |
| Dropout Voltage | 2 V at 25 °C - defines minimum VI–VO differential needed to sustain regulation; impacts minimum input supply design |
| Line Regulation | 50 mV (VI = 8–25 V, IO = 200 mA) - quantifies output stability against input voltage variation |
| Load Regulation | 50 mV (IO = 5–200 mA, TJ = 25 °C) - measures output deviation across typical load range |
| Quiescent Current | 6 mA - sets no-load power loss; enables low-standby-power system architectures |
| Supply Rejection | 62 dB (120 Hz, VI = 8–18 V) - determines AC ripple attenuation capability on input rail |
Pinout & Package
Package: TO-220FP (3-lead, full-pack, insulated tab). Thermal resistance junction-to-case is 5 °C/W, enabling reliable operation with modest heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Input) | Voltage input terminal | Accepts unregulated DC input (up to 35 V for VO = 5 V); requires 0.33 µF bypass capacitor near pin |
| 2 (Ground) | Circuit common reference | Provides return path for load and quiescent current; must be low-impedance connection to minimize noise and regulation error |
| 3 (Output) | Regulated 5 V output | Delivers stable 5 V to load; 0.1 µF capacitor recommended at pin for transient response improvement |
Key Features
| Feature | Design Value |
|---|---|
| Thermal overload protection | Automatic shutdown above safe junction temperature (150 °C max), preventing damage during sustained overloads |
| Short-circuit current limit | 300 mA typical short-circuit current (VI = 35 V), enabling safe fault containment without external fusing |
| SOA protection | Internal compensation limits power dissipation in pass transistor during high VI–VO differentials and heavy loads |
| Extended temperature range | 0 to 150 °C operating junction range (C version), supporting industrial and automotive under-hood environments |
| Fixed-output simplicity | No external feedback components required - reduces BOM count and layout complexity for dedicated 5 V rails |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Powering digital isolators, optocouplers, and level-shifting buffers in modular I/O racks. IC Role / Device Role / Timing Role: Local 5 V rail generator providing clean, isolated supply independent of main system rail. Use Value: Eliminates distribution losses and noise coupling from centralized supplies; thermal protection ensures reliability during field wiring faults. | Use Scenario: Supplying microcontroller peripherals (CAN transceivers, LIN drivers, EEPROM) in non-safety-critical body modules. IC Role / Device Role / Timing Role: Fixed 5 V regulator for mixed-signal subsystems requiring stable voltage despite battery voltage fluctuations (9–16 V). Use Value: 35 V absolute max input withstands load-dump transients; 0–150 °C junction range matches under-dash ambient requirements. |
| Medical Sensor Signal Conditioning | Point-of-Sale Terminal Power Management |
Use Scenario: Biasing precision op-amps and ADC references in portable diagnostic devices. IC Role / Device Role / Timing Role: Low-noise 5 V source (40 µV RMS noise, 10 Hz–100 kHz) for analog front-end circuitry. Use Value: Output noise specification directly supports 12-bit+ measurement accuracy; SOA protection prevents latch-up during ESD events. | Use Scenario: Regulating 5 V for USB host ports, display backlight drivers, and touch controller ICs in retail kiosks. IC Role / Device Role / Timing Role: Primary 5 V regulator feeding multiple downstream DC/DC converters and LDOs. Use Value: 500 mA output supports burst-mode loads (e.g., thermal printer activation); TO-220FP package allows through-hole mounting on cost-sensitive PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM78M05CDT | Same 5 V ±4 % output, 500 mA rating, TO-220FP package; identical pinout and thermal specs | No functional difference - direct second-source part with identical electrical and mechanical behavior | Select when dual-sourcing or lifecycle risk mitigation is required without redesign |
| L78L05ACZ | Lower output current (100 mA), tighter tolerance (±50 mV), TO-92 package, higher dropout (1.7 V min) | Not suitable for >100 mA loads; lacks thermal mass for sustained 500 mA operation | Use only in ultra-low-power, space-constrained applications where 500 mA capability is unnecessary |
Compared with LM78M05CDT, L78M05CDT-1 offers identical performance and sourcing from STMicroelectronics; versus L78L05ACZ, it delivers 5× higher current and superior thermal handling but requires larger board area and heatsinking.
Availability
L78M05CDT-1 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and medical sensor signal conditioning requiring stable component supply, long-term manufacturability, and consistent parametric performance across production batches.
Supply support for L78M05CDT-1 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, designing and manufacturing silicon solutions for automotive, industrial, and power management applications.
The L78M series belongs to ST's legacy linear regulator product line, engineered for cost-effective, robust local regulation in harsh environments where simplicity, reliability, and thermal resilience are prioritized over ultra-low quiescent current or switching efficiency.
FAQ
What is the maximum input voltage for L78M05CDT-1?
The absolute maximum DC input voltage is 35 V when regulating 5 V output. Exceeding this risks permanent damage. For reliable operation, keep input below 30 V with adequate heatsinking, especially at high ambient temperatures or near maximum load current.
Does L78M05CDT-1 require input and output capacitors?
Yes: a 0.33 µF capacitor is required between input and ground if the regulator is located more than ~2 inches from the main filter capacitor; a 0.1 µF capacitor is recommended at the output to improve transient response. Both must be placed with minimal lead length for stability.
How does thermal protection work in L78M05CDT-1?
Internal thermal sensing shuts down the output when junction temperature exceeds safe limits (typically ~150 °C). Operation resumes automatically once the die cools below the hysteresis threshold (~135 °C). This protects against destruction during overload, poor heatsinking, or high ambient conditions.
Can L78M05CDT-1 be used to generate adjustable output voltages?
Yes - though designed as a fixed 5 V regulator, it can be configured as an adjustable regulator using external resistors (e.g., Figure 19 in DS0425) or as a constant-current source (Figure 18). These configurations require careful attention to stability, SOA, and thermal limits beyond the standard 5 V use case.
L78M05CDT-1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-251-3 Short Leads, IPAK, TO-251AA
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 35V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 6 mA
- Current - Supply (Max):
- -
- PSRR:
- 62dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-251 (IPAK)
L78M05CDT-1 FAQ
1.How can I place an order for L78M05CDT-1 through Aetrix?
Please submit a Request for Quotation (RFQ) for L78M05CDT-1 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 L78M05CDT-1 reliable?
The price and inventory of L78M05CDT-1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78M05CDT-1 is usually 5 days.
3.What payment methods are accepted for L78M05CDT-1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78M05CDT-1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L78M05CDT-1?
L78M05CDT-1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L78M05CDT-1 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 L78M05CDT-1?
For technical support, including L78M05CDT-1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78M05CDT-1 requirements.
6.How does Aetrix verify that L78M05CDT-1 is sourced from the original manufacturer or authorized distributors?
All L78M05CDT-1 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 L78M05CDT-1 meets industry standards.
7.What is the process for return or replacement of L78M05CDT-1?
All L78M05CDT-1 units undergo pre-shipment inspection (PSI). If there is an issue with L78M05CDT-1, 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 L78M05CDT-1 part is unused and in its original packaging.
Return procedure for L78M05CDT-1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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