Datasheet

LT6650
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APPLICATIO S I FOR ATIO
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PI FU CTIO S
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BLOCK DIAGRA
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FB (Pin 1): Resistor Divider Feedback Pin. Connect a
resistor divider from OUT to GND and the center tap to FB.
This pin sets the output potential.
GND (Pin 2): Ground Connection.
DNC (Pin 3): Do not connect. Connected internally for post
package trim. This pin must be left unconnected.
IN (Pin 4): Positive Supply. Bypassing with a 1µF capacitor
is recommended if the output loading changes.
OUT (Pin 5): Reference Output. The output sources and
sinks current. It is stable with any load capacitor with a
total capacitance of 1µF or more. Higher load capacitance
improves load transient response.
OUT
DNC
FB
IN
GND
LT6650
–
+
V
R
= 400mV
REFERENCE
6650 BD
4
2
3
5
1
Long Battery Life
The LT6650 is a micropower, adjustable reference which
operates from supply voltages ranging from 1.4V to 18V.
The series regulated output may be configured with exter-
nal resistors to any voltage from 400mV to nearly the
supply potential. Under no-load conditions, the LT6650
dissipates only 8µW when operating on a 1.4V supply.
Other operating configurations allow the LT6650 to be
used as a micropower positive or negative adjustable
shunt reference from 1.4V to 18V.
Bypass and Load Capacitor
The LT6650 voltage reference requires a 1µF or greater
output capacitance for proper operation. This capacitance
may be provided by either a single capacitor connected
between OUT and GND or formed by the aggregate of
several capacitors that may be serving other decoupling
functions. Output impedance can be reduced by DC load-
ing of the output by 40µA to 200µA, and/or adding an R
Z
to the output capacitor for a 100µs time constant as shown
in Figure 1 and the Typical Performance Characteristics
graphs.
The LT6650 Voltage reference should have an input by-
pass capacitor of 0.1µF or larger. When the circuit is
Figure 1. LT6650 Input-Output Configuration
V
OUT
V
IN
OUT
IN
R
IN
FB
GND
LT6650
6650 F01
2
4 5
1
C
L
R
Z
C
IN