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| LP38511_14 Datasheet, PDF (11/19 Pages) Texas Instruments – 800 mA Fast-Transient Response Low-Dropout Linear Voltage Regulator with Error Flag | |||
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LP38511
www.ti.com
SNOSAU6D â NOVEMBER 2007 â REVISED MARCH 2009
The timing diagram in Figure 23 shows the relationship between the ERROR flag and the output voltage.
~2.50V
~2.25V
VIN ~1.55V
~1.25V
VOUT
NOM
~90%
~85%
Power-Up
Load
Transient
Line
Transient
Power-Down
1.80V
VERROR
Figure 23. ERROR Flag Operation, see Typical Application Circuit
~2.50V
~2.25V
VIN ~1.55V
~1.25V
VOUT
Power-Up
NOM
~90%
~85%
Load
Transient
Line
Transient
Power-Down
~2.50V
VERROR
~1.25V
Figure 24. ERROR Flag Operation, biased from VIN
POWER DISSIPATION/HEATSINKING
A heatsink may be required depending on the maximum power dissipation (PD(MAX)), maximum ambient
temperature (TA(MAX)) of the application, and the thermal resistance (θJA) of the package. Under all possible
conditions, the junction temperature (TJ) must be within the range specified in the Operating Ratings. The total
power dissipation of the device is given by:
PD = ( (VINâVOUT) x IOUT) + (VIN x IGND)
where
⢠IGND is the operating ground current of the device (specified under ELECTRICAL CHARACTERISTICS). (1)
The maximum allowable junction temperature rise (ÎTJ) depends on the maximum expected ambient
temperature (TA(MAX)) of the application, and the maximum allowable junction temperature (TJ(MAX)):
ÎTJ = TJ(MAX)â TA(MAX)
(2)
The maximum allowable value for junction to ambient Thermal Resistance, θJA, can be calculated using the
formula:
θJA = ÎTJ / PD(MAX)
(3)
Copyright © 2007â2009, Texas Instruments Incorporated
Product Folder Links: LP38511
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