A6303A
AiT Semiconductor Inc.
www.ait-ic.com
CMOS LOW DROPOUT REGULATOR (LDO)
300mA ULTRA-LOW NOISE, ULTRA-FAST RESPONSE
Where TJ (MAX) is the maximum operation junction temperature 125℃, TA is the ambient temperature and
the θJA is the junction to ambient thermal resistance. For recommended operating conitions specification of
A6303A, where TJ (MAX) is the maximum junction temperature of the die (125°C) and TA is the maximum
ambient temperature. The junction to ambient thermal resistance (θJ is layout dependent) for SOT-23,
A
SOT-25 package is 250°C/W, SC70-5 package is 333°C/W, on standard JEDEC 51-3 thermal test board. The
maximum power dissipation at TA = 25°C can be calculated by following formula:
The maximum power dissipation durepends on operating ambient temperature for fixed TJ (MAX) and thermal
resteance θJA. It is also useful to calculate the junction of temperature A6303A under a set of specific
conditions. In this example let the Input voltage VIN = 3.3V, the output current IOUT = 300mA and the case
temperature TA = 40℃ measured by a thermal couple during operation. The power dissipation for the VOUT
=
2.8V version of the version of the A6303A can be calculated as:
And the junction temperature, TJ, can be calculated as follows:vf
For this operating condition, TJ is lower than the absolute maximum operating junction temperature,125°C, so
it is safe to use the A6303A in this configuration.
Layout considerations
To improve ac performance such as PSRR, output noise, and transient response, it is recommended that the
PCB be designed with separate ground planes for VIN and VOUT, with each ground plane connected only at the
GND pin of the device.
REV1.4
-DEC 2009 RELEASED, NOV 2011 UPDATED -
- 10 -
AITSEMI [ AiT Semiconductor ]
