8 Application and Implementation
SNVS037G – SEPTEMBER 1999 – REVISED JANUARY 2015
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LM1084 is versatile in its applications, including uses in programmable output regulation and local on-card
regulation. Or, by connecting a fixed resistor between the ADJUST and OUTPUT terminals, the LM1084 can
function as a precision current regulator. An optional output capacitor can be added to improve transient
response. The ADJUST terminal can be bypassed to achieve very high ripple-rejection ratios, which are difficult
to achieve with standard three-terminal regulators. Please note, in the following applications, if ADJ is mentioned,
it makes use of the adjustable version of the part, however, if GND is mentioned, it is the fixed voltage version of
8.2 Typical Applications
8.2.1 1.2-V to 15-V Adjustable Regulator
This part can be used as a simple low drop out regulator to enable a variety of output voltages needed for
demanding applications. By using an adjustable R2 resistor a variety of output voltages can be made possible as
shown in Figure 16 based on the LM1084-ADJ.
Figure 16. 1.2-V to 15-V Adjustable Regulator
22.214.171.124 Design Requirements
The device component count is very minimal, employing two resistors as part of a voltage divider circuit and an
output capacitor for load regulation.
126.96.36.199 Detailed Design Procedure
The voltage divider for this part is set based on the equation shown in Figure 16, where R1 is the upper feedback
resistor and R2 is the lower feedback resistor.
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