LT1999-10/LT1999-20/
LT1999-50
12
1999fb
pin FuncTions
V+ (Pins 1, 4): Power Supply Voltage. Pins 1 and 4 are
tied internally together. The specified range of operation
is 4.5V to 5.5V, but lower supply voltages (down to ap-
proximately 4V) is possible although the LT1999 is not
tested or characterized below 4.5V. See the Applications
Information section.
+IN (Pin 2): Positive Sense Input Pin.
–IN (Pin 3): Negative Sense Input Pin.
GND (Pin 5): Ground Pin.
REF (Pin 6): Reference Pin Input. The REF pin sets the
output common mode level and is set halfway between V+
and GND using a divider made of two 160k resistors. The
default open circuit potential of the REF pin is mid-supply.
It can be overdriven by an external voltage source cable
of driving 80k to a mid-supply potential (see the Electrical
Characteristics table for its specified input voltage range).
OUT (Pin 7): Voltage Output. VOUT = AV(VSENSE ± VOSI),
where AV is the gain, and VOSI is the input referred off-
set voltage. The output amplifier has a low impedance
output and is designed to drive up to 200pF capacitive
loads directly. Capacitive loads exceeding 200pF should
be decoupled with an external resistor of at least 100Ω.
SHDN (Pin 8): Shutdown Pin. When pulled to within 0.5V
of GND (Pin 5), will place the LT1999 into low power
shutdown. If the pin is left floating, an internal 2A pull-
up current source will place the LT1999 into the active
(amplifying) state.