TPS7A78 - 120mA Smart Cap-Drop LDO | Texas Instruments
MPN: TPS7A78 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.5 | $1.50 |
| 10 | $1.35 | $13.50 |
| 100 | $1.2 | $120.00 |
| 500 | $1.1 | $550.00 |
| 1,000 | $1 | $1,000.00 |
Drop-in alternatives for TPS7A78 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
TPS7A7833PWPR
β Drop-Inπ Reference alternative (not in catalog)
TPS7A7850PWPR
β Drop-Inπ Reference alternative (not in catalog)
TPS7A78 Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage Options | 3.3V, 5V |
| Maximum Output Current | 120 mA |
| Input Voltage Range (AC) | 85 VAC to 265 VAC |
| Architecture | Capacitance-drop (cap-drop) with active bridge rectifier |
| Quiescent Current | [DATA_NEEDED: quiescent current] |
| Dropout Voltage | [DATA_NEEDED: dropout voltage] |
| Line Regulation | [DATA_NEEDED: line regulation] |
| Load Regulation | [DATA_NEEDED: load regulation] |
| Output Noise | [DATA_NEEDED: output noise] |
| PSRR | [DATA_NEEDED: PSRR] |
| Operating Temperature Range | [DATA_NEEDED: operating temperature range] |
| Package | 14-pin HTSSOP (PWP) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
TPS7A78 Pin Configuration
| Pin 1 | AC1 β AC input terminal 1 |
| Pin 2 | AC2 β AC input terminal 2 |
| Pin 3 | CS β Cap-drop capacitor connection |
| Pin 4 | GND β Ground |
| Pin 5 | OUT β Regulated output voltage |
| Pin 6 | NC β No connect |
| Pin 7 | NC β No connect |
| Pin 8 | NC β No connect |
| Pin 9 | NC β No connect |
| Pin 10 | NC β No connect |
| Pin 11 | NC β No connect |
| Pin 12 | NC β No connect |
| Pin 13 | NC β No connect |
| Pin 14 | NC β No connect |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
TPS7A78 is suitable for 6 applications: Smart Meters, Home Automation, IoT Devices, LED Lighting, Home Appliances, Industrial Controls.
Smart Meters
The TPS7A78 provides a compact, transformerless power supply for smart meters, converting AC mains directly to a regulated DC rail. Its 120mA output can power metering ICs, communication modules, and display drivers. The wide input range (85-265VAC) ensures global compatibility, while the low standby power helps meet energy regulations. The active bridge rectifier minimizes power loss, improving overall efficiency in always-on metering applications.
Recommended
Home Automation
In home automation, the TPS7A78 powers smart switches, thermostats, and sensors directly from AC mains without a transformer. Its compact HTSSOP package fits into wall-mounted enclosures, and the 120mA output is sufficient for MCUs, wireless transceivers, and relay drivers. The low quiescent current and high efficiency reduce standby power, essential for energy-efficient smart home devices. The cap-drop architecture eliminates magnetic components, reducing EMI and cost.
Recommended
IoT Devices
The TPS7A78 is ideal for IoT devices that need a compact, low-cost power supply from AC mains. It can power sensors, gateways, and smart plugs, providing a regulated 3.3V or 5V rail. The 120mA output supports typical IoT loads, and the wide input range allows use in any country. The transformerless design reduces size and weight, making it suitable for space-constrained devices. Its low standby power is critical for battery-less, always-on IoT nodes.
Recommended
LED Lighting
The TPS7A78 can power control circuits in LED lighting, such as smart bulbs and LED drivers. It provides a regulated DC supply for the microcontroller and communication ICs, while the LED driver handles the high-current LED string. The compact package fits into bulb bases, and the transformerless design reduces cost and size. The 120mA output is sufficient for control logic, and the wide input range supports global mains voltages. The active bridge rectifier improves efficiency, reducing heat in enclosed fixtures.
Recommended
Home Appliances
The TPS7A78 provides a compact power supply for home appliances like washing machines, air conditioners, and refrigerators, powering control boards and user interfaces. Its transformerless design saves space and cost compared to traditional supplies. The 120mA output can power MCUs, displays, and sensors. The wide input range (85-265VAC) ensures operation in any region. The low standby power helps appliances meet energy efficiency standards, and the active bridge rectifier reduces power loss.
Recommended
Industrial Controls
In industrial settings, the TPS7A78 can power low-power control circuits, sensors, and communication interfaces directly from AC mains. Its robust design includes thermal shutdown and overcurrent protection, ensuring reliability in harsh environments. The 120mA output is suitable for PLC I/O modules, motor controllers, and monitoring equipment. The wide input range accommodates industrial mains variations, and the compact package allows dense PCB layouts. The transformerless approach reduces cost and EMI, beneficial for industrial applications.
Recommended
Recommended Products Summary
Engineering reference data for TPS7A78 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TPS7A7833PWPR | TPS7A7850PWPR | UCC28730-Q1 |
|---|---|---|---|---|
| Package | 14-HTSSOP | 14-HTSSOP | 14-HTSSOP | SOT-23-6 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Current | 120 mA | 120 mA | 120 mA | [DATA_NEEDED] |
| Output Voltage | 3.3V or 5V | 3.3V | 5V | [DATA_NEEDED] |
| Input Voltage (AC) | 85-265 VAC | 85-265 VAC | 85-265 VAC | [DATA_NEEDED] |
| Architecture | Cap-drop LDO | Cap-drop LDO | Cap-drop LDO | Flyback controller |
| Pin Compatibility | Reference | Pin-compatible | Pin-compatible | Not pin-compatible |
| Transformer Required | No | No | No | Yes (external) |
Key Differentiators
- Integrated active bridge rectifier (vs UCC28730-Q1)
- Transformerless AC/DC conversion (vs LNK304)
- Fixed output options (vs UCC28810)
Design Notes
Place the external cap-drop capacitor (CS) close to the AC input pins to minimize parasitic inductance and ensure stable operation. Use a capacitor with appropriate voltage rating (at least 400V for 265VAC input) and X2 safety rating for AC mains applications. Keep high-voltage traces short and isolated from low-voltage output traces to prevent noise coupling.
The TPS7A78 dissipates power proportional to the voltage drop across the internal LDO and the load current. At 120mA output and high input voltage, power dissipation can be significant. Use the exposed thermal pad on the HTSSOP package and provide adequate copper area on the PCB for heat sinking. Evaluate worst-case thermal conditions and ensure junction temperature stays within limits.
Do not operate the TPS7A78 without the external cap-drop capacitor (CS) as it is essential for current limiting. Ensure the capacitor is rated for the full AC input voltage and has appropriate safety certifications (e.g., X2). Also, verify that the output capacitor is properly sized for stability, as specified in the datasheet. Incorrect component selection can lead to overvoltage or instability.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified. Other compliance details not specified in available data.
