December 2006 Rev. 20 1/38
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LD1117 series
Low drop fixed and adjustable positive voltage regulators
Feature summary
■ Low dropout voltage (1V TYP.)
■ 2.85V Device performances are suitable for
SCSI-2 active termination
■ Output current up to 800 mA
■ Fixed output voltage of: 1.2V, 1.8V, 2.5V,
2.85V, 3.0V, 3.3V, 5.0V
■ Adjustable version availability (V
rel
=1.25V)
■ Internal current and thermal limit
■ Available in ± 1% (at 25°C) and 2% in full
temperature range
■ Supply voltage rejection: 75dB (typ.)
Description
The LD1117 is a LOW DROP Voltage Regulator
able to provide up to 800mA of Output Current,
available even in adjustable version (Vref=1.25V).
Concerning fixed versions, are offered the
following Output Voltages: 1.2V,1.8V,2.5V,2.85V,
3.0V 3.3V and 5.0V. The 2.85V type is ideal for
SCSI-2 lines active termination. The device is
supplied in: SOT-223, DPAK, SO-8 and TO-220.
The SOT-223 and DPAK surface mount packages
optimize the thermal characteristics even offering
a relevant space saving effect. High efficiency is
assured by NPN pass transistor. In fact in this
case, unlike than PNP one, the Quiescent Current
flows mostly into the load. Only a very common
10µF minimum capacitor is needed for stability.
On chip trimming allows the regulator to reach a
very tight output voltage tolerance, within ± 1% at
25°C. The ADJUSTABLE LD1117 is pin to pin
compatible with the other standard. Adjustable
voltage regulators maintaining the better
performances in terms of Drop and Tolerance.
DPAK
SO-8
TO-220
SOT-223
www.st.com
Block diagram
