AC7801-LDO
AEC-Q100 qualified LDO with 300mA output, wide input range, and comprehensive automotive protections
Product Overview
Description
The AC7801-LDO is an automotive-qualified low-dropout linear regulator designed for vehicle electronics power supply.
With 3.5V to 40V input range, 300mA output current, and 50 microamps quiescent current, it is ideal for ECU and sensor power applications.
The device includes comprehensive automotive protections including load dump protection and thermal shutdown.
Product Series
AC
Primary Application
ECU power supply
Key Features
- Wide 3.5V to 40V input voltage range
- Fixed 3.3V or 5V output options
- 300mA maximum output current
- Low 350mV dropout at full load
- Low 50 microamps quiescent current
- Load dump protection to 40V
- Thermal shutdown and current limiting
- AEC-Q100 Grade 1 qualified
Specifications
| Input Voltage | 3.5V to 40V |
|---|---|
| Output Voltage | 3.3V or 5V fixed |
| Output Current | 300mA |
| Dropout Voltage | 350mV at 300mA |
| Quiescent Current | 50 microamps |
| PSRR | 60dB at 1kHz |
| Package | SOP-8, TSSOP-8 |
Applications
ECU power supply
Power conversion and supply
Sensor power supply
Power conversion and supply
ADAS system power
Automotive and EV electronics
Infotainment power
Electronic system design
Always-on standby power
Electronic system design
FAE Expert Insights
"The AC7801-LDO is my standard recommendation for automotive power supply applications. The 3.5V to 40V input range covers all vehicle electrical conditions including cold cranking and load dump transients. I have successfully used this LDO in multiple ECU and sensor power supply designs with excellent reliability. The 50 microamps quiescent current is excellent for always-on circuits, minimizing battery drain during vehicle standby. The load dump protection per ISO 7637-2 is essential for automotive applications, eliminating the need for external protection components. The dropout voltage of 350mV at 300mA is reasonable for automotive applications where input voltage is typically well above output voltage. Overall, this LDO offers excellent value for automotive power supply applications."
Automotive LDO with wide input range and load dump protection for reliable vehicle power
— Dr. Michael Chen, BeiLuo
Frequently Asked Questions
What is the dropout voltage of AC7801-LDO?
The AC7801-LDO features typical dropout voltage of 350mV at maximum load current of 300mA. At lighter loads, dropout voltage is proportionally lower. The dropout voltage allows the LDO to maintain regulation when input voltage is close to output voltage, which is important during vehicle cold cranking conditions when battery voltage may drop significantly.
Ensure minimum input voltage exceeds output voltage plus dropout voltage under all operating conditions.
Does AC7801-LDO protect against load dump conditions?
Yes, the AC7801-LDO includes internal protection against automotive load dump conditions up to 40V per ISO 7637-2 standard. Load dump occurs when the alternator generates high voltage transients during battery disconnection. The LDO's 40V maximum input rating accommodates these transients without external protection components, simplifying design and reducing BOM cost.
AC7801-LDO internal load dump protection eliminates need for external TVS diodes in most applications.
What is the PSRR of AC7801-LDO?
The AC7801-LDO provides Power Supply Rejection Ratio (PSRR) of 60dB at 1kHz and 40dB at 100kHz. This high PSRR effectively attenuates input voltage ripple and noise, providing clean output voltage for sensitive automotive electronics. The good PSRR performance is maintained across the operating temperature range, ensuring consistent noise rejection in vehicle environments.
60dB PSRR is sufficient for most automotive applications. Contact LiTong for noise-sensitive analog applications.
What thermal package options are available?
The AC7801-LDO is available in SOP-8 and TSSOP-8 packages with exposed thermal pad options for improved heat dissipation. The SOP-8 package provides better thermal performance with larger copper area for heat sinking. The TSSOP-8 offers smaller footprint for space-constrained designs. Proper PCB layout with adequate copper area is essential for thermal management at maximum load current.
Select SOP-8 for better thermal performance, TSSOP-8 for compact designs.
Can AC7801-LDO be used for safety-critical applications?
The AC7801-LDO is designed for general automotive applications (QM quality level) and does not include specific functional safety features. For safety-critical applications requiring ASIL compliance, consider using multiple LDOs for redundancy or select PMICs with integrated safety monitoring. The LDO can be used in safety-related systems when combined with external safety monitoring and appropriate system-level safety mechanisms.
Use AC7801-LDO for non-safety-critical power supply. Contact LiTong for safety-critical power solutions.