TPS7A78 120-mA smart AC/DC low-dropout (LDO) linear voltage regulator |

This product has been released to the market and is available for purchase. For some products, newer alternatives may be available.
120-mA smart AC/DC low-dropout (LDO) linear voltage regulator



The TPS7A78 improves the overall efficiency and standby-power in power-supplies in an easy-to-use, non-magnetic approach to AC/DC conversion. The TPS7A78 uses a capacitor-drop architecture to lower the AC source voltage before actively clamping the rectified voltage. The device then regulates this rectified voltage down to the application-specific operating voltage. The unique architecture of the device allows the standby power to be reduced to just a few 10s of milliwatts. The TPS7A78 switched-capacitor stage reduces power losses by stepping down the rectified input voltage by a factor of four and increasing the output-to-input current by the same ratio, as given by PIN ≅ POUT and VIN ≅ VOUT × 4. Compared to a traditional capacitor-drop (cap-drop) stage, this step down reduces input current, thus minimizing the value of the capacitance needed.

Electricity-metering applications, where the power supply must be reliable and magnetic tamper-proof, benefits from using the TPS7A78 because this device does not require external magnetics. This feature makes complying with IEC 61000-4-8 easier while minimizing magnetic shielding cost.

Additionally, the TPS7A78 also comes with a user-programmable, power-fail detection threshold that can provide an early alert to power failures and enable shutdown before complete power loss. The power-good indicator (PG) is also provided for sequencing or resetting a microcontroller.

The TPS7A78 is available in a 14-pin HTSSOP (PWP) package.


  • Non-isolated power solution for ≥ 18 VAC RMS:
    • Up to 75% efficiency
    • Standby power consumption: 15 mW (typical)
    • Line-voltage, cap-drop capacitor as small as 1/4th the size of linear solutions
  • Available in fixed output voltages:
    • 1.3 V to 5 V (50-mV steps)
  • Power-fail detection
  • Power-good indication
  • 1% typical accuracy
  • Package:
    • 5-mm × 6.5-mm HTSSOP-14 (PWP)

All trademarks are the property of their respective owners.


Compare all products in Linear regulators (LDO) Email Download to Excel
Part number Order Output options Iout (Max) (A) Vin (Max) (V) Vin (Min) (V) Vout (Max) (V) Vout (Min) (V) Fixed output options (V) Package Group Features Regulated outputs (#) Operating temperature range (C) Thermal resistance θJA (°C/W) Approx. price (US$) Rating Accuracy (%) Iq (Typ) (mA) Package size: mm2:W x L (PKG)
TPS7A78 Order now Fixed Output     0.12     23     17     5     1.25     3.3
HTSSOP | 14     Power-Fail Detect
Power Good
AC/DC Regulation    
1     -40 to 125     48     0.88 | 1ku     Catalog     2     0.28     14HTSSOP: 32 mm2: 6.4 x 5 (HTSSOP | 14)