AS2886
Basic Adjustable Regulator
V IN
VOUT
AS2886
R1
R2
VREF
IADJ
50µA
VOUT = VREF * ( 1 + R/R1) + IADJ * R2
2
Fig.2 Basic Adjustable Regulator
Output Voltage
Consider Figure 2. The resistance R1 generates a constant
current flow, normally the specified load current of 10mA.
This current will go through the resistance R2 to set the overall
output voltage. The current IADJ is very small and constant.
Therefore its contribution to the overall output voltage is very
small and can generally be ignored
Load Regulation
Parasitic line resistance can degrade load regulation. In order
not to affect the behavior of the regulator, it is best to connect
directly the R1 resistance from the resistor divider to the case,
and not to the load. For the same reason, it is best to connect
the resistor R2 to the Negative side of the load.
R
P Parasitic Line
Resistance
VIN
AS2886
Connect R 1 to
Case of Regulator
R1
RL
R2
Connect R 2 to Load
Fig.3 Basic Adjustable Regulator
Rev. 10/11/00
SIPEX [ SIPEX CORPORATION ]
