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Texas Instruments UA78M08CDCYG3
- Part No.:
- UA78M08CDCYG3
- Manufacturer:
- Texas Instruments
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
UA78M08CDCYG3.pdf
- Description:
- IC REG LINEAR 8V 500MA SOT223-4
- Quantity:
- Payment:
- Shipping:
Inventory:718
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Product details
Overview
UA78M08CDCYG3 from Texas Instruments is a fixed-output 8V, 500mA positive-voltage linear regulator in SOT-223 (DCY) package, designed for on-card regulation to suppress post-regulation noise and distribution issues in distributed power systems. It operates across 10.5V–25V input range, delivers stable 8V ±0.3V output with 2.0V dropout, and integrates short-circuit current limiting and thermal shutdown for robust protection in residential and industrial power rails.
For engineers reviewing the UA78M08CDCYG3 datasheet, UA78M08CDCYG3 pinout, UA78M08CDCYG3 application, or UA78M08CDCYG3 equivalent, this page provides verified electrical specs, thermal behavior, legacy-chip-specific performance boundaries, and real-world implementation guidance for washers, battery backup units, and air conditioner outdoor unit power supplies.
Technical Context
The UA78M08CDCYG3 is a legacy-chip variant of the UA78M family, characterized for 0°C to +125°C junction temperature and absolute maximum input voltage of 35V. Its internal pass transistor uses voltage-headroom–dependent current limiting to maintain safe SOA across VI–VO differentials up to 25V, with thermal shutdown triggered at ~150°C and hysteresis enabling automatic recovery.
Unlike newer UA78M variants, this part exhibits higher bias current (4.5–6 mA), lower ripple rejection (56 dB at 120 Hz, IO = 100 mA), and wider load regulation (25–160 mV over 5–500 mA), reflecting its legacy design optimized for cost-sensitive, non-automotive applications requiring stable 8V rail generation without external compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 8.0 V ±0.3 V (min/max over 5–500 mA load, 0°C to 125°C) |
| Max Output Current | 500 mA continuous - supports mid-power subsystems without heatsinking under typical ambient conditions |
| Input Voltage Range | 10.5 V to 25 V - ensures regulation across wide-line AC-DC outputs and battery-derived supplies |
| Dropout Voltage | 2.0 V at 500 mA - defines minimum headroom needed to sustain 8V output; requires ≥10V input at full load |
| Quiescent Current | 4.5–6 mA - impacts no-load efficiency and standby power in always-on systems like BBU controllers |
| Thermal Resistance | RθJA = 53°C/W (DCY package) - determines junction temperature rise under 500 mA load at given PCB copper area |
| Short-Circuit Current | 250 mA at VIN = 35 V - limits fault power dissipation to prevent thermal runaway during sustained shorts |
Pinout & Package
SOT-223 (DCY) 3-pin thermally enhanced package (6.5 mm × 7 mm), with exposed thermal pad connected internally to COMMON pin for improved heat transfer to PCB copper pour.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: INPUT | Unregulated DC input supply | Accepts 10.5–25 V; requires 0.33 µF ceramic capacitor placed adjacent to pin for transient stability |
| 2: COMMON | Ground reference and thermal path | Common return for input/output capacitors and load; must be low-impedance connection to PCB ground plane |
| 3: OUTPUT | Regulated 8 V DC output | Delivers up to 500 mA; requires 0.1 µF ceramic capacitor near pin to improve load transient response |
Key Features
| Feature | Design Value |
|---|---|
| Stable without external components | Operates with only 0.33 µF input and 0.1 µF output capacitors - eliminates need for compensation networks or feedback resistors |
| Legacy-chip thermal protection | Thermal shutdown activates at ~150°C junction temperature with hysteresis - prevents permanent damage during overload or poor heatsinking |
| Voltage-headroom–adaptive current limit | Reduces short-circuit current as (VIN – VOUT) increases - maintains safe SOA across full input range without external foldback circuitry |
| Fixed 8 V output tolerance | ±3.75% over full temperature and load range - meets requirements for non-critical logic and analog subsystems in white goods |
| Low-noise operation | 52 µVrms output noise (10 Hz–100 kHz) - suitable for powering comparators, op-amps, and microcontroller peripherals without added filtering |
Applications
| Washers and Dryers | Battery Backup Units (BBU) |
|---|---|
|
Use Scenario: Powering control logic, display drivers, and sensor interfaces in residential laundry appliances with wide-input AC-DC supplies. IC Role / Device Role / Timing Role: Primary 8V local regulator converting 12–24V intermediate rail to stable MCU and peripheral supply. Use Value: Eliminates need for external LDO or filter stages while maintaining <±50 mV load regulation across motor startup transients. |
Use Scenario: Providing conditioned 8V rail for charging management ICs and status monitoring circuits during AC mains failure. IC Role / Device Role / Timing Role: Standby power regulator maintaining system state during brownout or battery switchover events. Use Value: 250 mA short-circuit current limit prevents catastrophic failure when backup battery polarity is reversed or cell fails shorted. |
| Air Conditioner Outdoor Units | Residential Lighting Controls |
|
Use Scenario: Regulating auxiliary 8V supply for fan motor drivers, communication modules, and environmental sensors in high-temperature outdoor enclosures. IC Role / Device Role / Timing Role: High-reliability linear regulator operating continuously at 0°C to 125°C junction temperature. Use Value: RθJA = 53°C/W enables operation at 500 mA with ≤30°C rise on 2 oz copper, avoiding costly heatsinks in space-constrained housings. |
Use Scenario: Delivering clean 8V power to dimmer ICs, LED driver controllers, and wireless connectivity modules in smart lighting fixtures. IC Role / Device Role / Timing Role: Low-noise local regulator decoupling switching converter ripple from sensitive analog timing circuits. Use Value: 52 µVrms noise and 56 dB PSRR at 120 Hz suppress line-frequency artifacts that cause visible LED flicker. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM78M08CDT/NOPB | Same 8V/500mA output, TO-252 (KVU) package, RθJA = 30.2°C/W, but higher quiescent current (6–8 mA) and no legacy/new chip differentiation | Preferred where board-level thermal resistance is >40°C/W and PCB layout allows larger footprint | Select for lower junction temperature rise in high-ambient environments; verify compatibility with existing SOT-223 footprint |
| UA78M08CKVURG3 | Same electrical specs, but TO-252 (KVU) package with RθJA = 30.2°C/W (legacy chip), 3.3°C/W RθJC(bot), and 35V absolute max input | Used in higher-power designs requiring direct thermal pad soldering to heatsink or large copper area | Choose when thermal performance is critical and mechanical constraints permit TO-252 mounting; not pin-compatible with DCY |
Compared with LM78M08CDT/NOPB and UA78M08CKVURG3, the UA78M08CDCYG3 offers the smallest PCB footprint and lowest assembly cost in SOT-223, while delivering identical 8V regulation and legacy-chip reliability-making it optimal for space-constrained, cost-sensitive residential appliance designs where thermal margin is sufficient.
Availability
UA78M08CDCYG3 is available at Aetrix Electronics and suitable for washers and dryers, battery backup units (BBU), and air conditioner outdoor units requiring stable component supply with consistent legacy-chip performance and long-term manufacturability.
Supply support for UA78M08CDCYG3 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in linear regulator design and manufacturing.
The UA78M product line delivers cost-optimized, fixed-output linear regulators for consumer and industrial applications where simplicity, reliability, and wide-input operation outweigh ultra-low quiescent current or automotive qualification requirements.
FAQ
What is the maximum input voltage rating for UA78M08CDCYG3?
The UA78M08CDCYG3 is a legacy-chip variant rated for an absolute maximum input voltage of 35 V. Exceeding this voltage risks permanent damage, even if duration is brief. For designs requiring higher input tolerance, TI offers newer UA78M variants rated to 45 V, but those are not drop-in replacements for UA78M08CDCYG3 due to differing thermal and noise characteristics.
Does UA78M08CDCYG3 require external capacitors for stability?
No-UA78M08CDCYG3 is internally compensated and stable without external components. However, TI recommends a 0.33 µF ceramic capacitor at the INPUT pin and a 0.1 µF ceramic capacitor at the OUTPUT pin to suppress high-frequency noise and improve transient response. These values are not for stability but for system-level EMI and load-step performance.
What is the guaranteed output voltage tolerance of UA78M08CDCYG3 over temperature and load?
UA78M08CDCYG3 guarantees 7.7 V to 8.3 V output (±3.75%) across 5–500 mA load current and 0°C to +125°C junction temperature. At 25°C and 350 mA, typical output is 8.0 V with ±0.1 V variation. This tolerance reflects legacy-chip process variation and is tighter than earlier 78M series but looser than modern LDOs.
How does thermal shutdown behave in UA78M08CDCYG3 during sustained overload?
UA78M08CDCYG3 enters thermal shutdown when junction temperature reaches ~150°C, disabling output until temperature falls to ~135°C (typical hysteresis). During continuous overload, it cycles on/off-this protects the die but causes output voltage interruption. To avoid cycling, ensure PCB copper area and airflow keep RθJA ≤ 53°C/W at peak load and ambient.
Can UA78M08CDCYG3 replace older UA78M08C variants in existing designs?
Yes-UA78M08CDCYG3 is a direct replacement for legacy UA78M08C parts in SOT-223 (DCY) package, sharing identical pinout, electrical specs, thermal ratings, and recommended operating conditions. The "G3" suffix denotes TI's green packaging standard (lead-free, RoHS-compliant), with no functional or performance change from prior UA78M08C versions.
UA78M08CDCYG3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-261-4, TO-261AA
- Packaging:
- Bulk
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 2V @ 350mA
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 80dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-223-4
UA78M08CDCYG3 FAQ
1.How can I place an order for UA78M08CDCYG3 through Aetrix?
Please submit a Request for Quotation (RFQ) for UA78M08CDCYG3 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 UA78M08CDCYG3 reliable?
The price and inventory of UA78M08CDCYG3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UA78M08CDCYG3 is usually 5 days.
3.What payment methods are accepted for UA78M08CDCYG3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UA78M08CDCYG3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UA78M08CDCYG3?
UA78M08CDCYG3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UA78M08CDCYG3 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 UA78M08CDCYG3?
For technical support, including UA78M08CDCYG3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UA78M08CDCYG3 requirements.
6.How does Aetrix verify that UA78M08CDCYG3 is sourced from the original manufacturer or authorized distributors?
All UA78M08CDCYG3 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 UA78M08CDCYG3 meets industry standards.
7.What is the process for return or replacement of UA78M08CDCYG3?
All UA78M08CDCYG3 units undergo pre-shipment inspection (PSI). If there is an issue with UA78M08CDCYG3, 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 UA78M08CDCYG3 part is unused and in its original packaging.
Return procedure for UA78M08CDCYG3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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