TPS7A78 - 120mA Smart Cap-Drop LDO | Texas Instruments
部品番号: TPS7A78 ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 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 |
TPS7A78 概要
A capacitance-drop regulator is a type of AC/DC converter that uses a capacitor to drop the AC voltage before rectification and regulation. Unlike traditional transformer-based supplies, it is non-isolated and relies on a series capacitor to limit current, making it lightweight and cost-effective. The TPS7A78 belongs to the family of linear voltage regulators, specifically smart LDOs that integrate active rectification and clamping to improve efficiency and standby power.
Key features include a wide input voltage range of 85VAC to 265VAC, a fixed output voltage of 3.3V or 5V, and a maximum output current of 120mA. The device achieves high efficiency by actively clamping the rectified voltage, reducing power dissipation. It also features low quiescent current, thermal shutdown, and overcurrent protection, ensuring robust operation in harsh environments. The TPS7A78 is available in a 14-pin HTSSOP (PWP) package, which provides excellent thermal performance and a compact footprint.
Technically, the TPS7A78 integrates a full-wave bridge rectifier using internal MOSFETs, which are controlled to minimize voltage drop and power loss. The external cap-drop capacitor (CS) is selected based on the desired output current and input voltage, allowing designers to optimize the trade-off between size and performance. The device also includes an internal clamp that limits the rectified voltage to a safe level, protecting downstream circuitry from overvoltage conditions.
Typical applications include smart meters, home automation, IoT devices, LED lighting, and other low-power appliances that require a compact, non-isolated power supply. The TPS7A78 is particularly suited for applications where space is limited and where magnetic components are undesirable due to cost or EMI concerns. Its high efficiency and low standby power make it ideal for always-on devices that need to meet stringent energy regulations.
When designing with the TPS7A78, it is critical to select the appropriate cap-drop capacitor (CS) value and voltage rating based on the input voltage and load current. Additionally, proper PCB layout is essential to minimize parasitic inductance and ensure stable operation. The device's thermal performance should be evaluated under worst-case conditions, and adequate copper area should be provided for heat dissipation.
ドロップイン代替品: TPS7A78 — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
クイック比較ツール — 並列比較する代替部品を選択:
TPS7A7833PWPR
✅ ドロップイン📋 参考代替品（カタログ未掲載）
TPS7A7850PWPR
✅ ドロップイン📋 参考代替品（カタログ未掲載）
TPS7A78 最大定格＆電気的特性
| 出力タイプ | Fixed |
| Output Voltage Options | 3.3V, 5V |
| 最大出力電流 | 120 mA |
| Input Voltage Range (AC) | 85 VAC to 265 VAC |
| Architecture | Capacitance-drop (cap-drop) with active bridge rectifier |
| パッケージ | 14-pin HTSSOP (PWP) |
| 実装タイプ | Surface Mount |
| RoHS ステータス | Compliant |
TPS7A78 ピン構成
| ピン 1 | AC1 — AC input terminal 1 |
| ピン 2 | AC2 — AC input terminal 2 |
| ピン 3 | CS — Cap-drop capacitor connection |
| ピン 4 | GND — Ground |
| ピン 5 | OUT — Regulated output voltage |
| ピン 6 | NC — No connect |
| ピン 7 | NC — No connect |
| ピン 8 | NC — No connect |
| ピン 9 | NC — No connect |
| ピン 10 | NC — No connect |
| ピン 11 | NC — No connect |
| ピン 12 | NC — No connect |
| ピン 13 | NC — No connect |
| ピン 14 | NC — No connect |
主な用途
TPS7A78 の用途: 6 件s: 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.
おすすめ
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.
おすすめ
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.
おすすめ
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.
おすすめ
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.
おすすめ
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.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: TPS7A78 — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | TPS7A7833PWPR | TPS7A7850PWPR | UCC28730-Q1 |
|---|---|---|---|---|
| Package | 14-HTSSOP | 14-HTSSOP | 14-HTSSOP | SOT-23-6 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| 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) |
主な差別化要因
- Integrated active bridge rectifier （vs UCC28730-Q1)
- Transformerless AC/DC conversion （vs LNK304)
- Fixed output options （vs UCC28810)
設計ノート
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.
コンプライアンス情報
RoHS compliant per TI product page. Not AEC-Q100 qualified. Other compliance details not specified in available data.
