LT1782 Linear Technology, LT1782 Datasheet - Page 9

• Manufacturer Part Number: LT1782
• Description: Micropower/ Over-The-Top SOT-23/ Rail-to-Rail Input and Output Op Amp
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
sourcing current is reduced to 10mA at 3V total supplies
as noted in the Electrical Characteristics.
The LT1782 is internally compensated to drive at least
600pF of capacitance under any output loading condi-
tions. A 0.22 F capacitor in series with a 150 resistor
between the output and ground will compensate these
amplifiers for larger capacitive loads, up to 10,000pF, at all
output currents.
Distortion
There are two main contributors to distortion in op amps:
output crossover distortion as the output transitions from
sourcing to sinking current, and distortion caused by
nonlinear common mode rejection. If the op amp is
operating inverting, there is no common mode induced
distortion. If the op amp is operating in the PNP input stage
(input is not within 0.8V of V
typically 100dB. When the LT1782 switches between
input stages, there is significant nonlinearity in the CMRR.
Lower load resistance increases the output crossover
distortion but has no effect on the input stage transition
distortion. For lowest distortion, the LT1782 should be
SI PLIFIED
W
SHDN
Q26
J1
Q25
Q23
+
2 A
U
SCHE ATIC
Q24
R1
30k
Q5
U
Q1
Q4
W
+
– IN
+IN
), the CMRR is very good,
Q6
W
R2
R3
6k
6k
D4
U
D5
Q9
Q7
Q8
D1
Q10
operated single supply, with the output always sourcing
current and with the input voltage swing between ground
and (V
istics curves, “Total Harmonic Distortion + Noise vs Ouput
Voltage Amplitude.”
Gain
The open-loop gain is almost independent of load when
the output is sourcing current. This optimizes perfor-
mance in single supply applications where the load is
returned to ground. The typical performance curve of
open-loop gain for various loads shows the details.
Shutdown
The 6-lead part includes a shutdown feature that disables
the part, reducing quiescent current and making the
output high impedance. The part can be shut down by
bringing the SHDN pin 1.2V or more above V
down, the supply current is about 5 A and the output
leakage current is less than 1 A (V
normal operation, the SHDN pin can be tied to V
floating. See the Typical Performance Characteristics
curves, “Supply Current vs Shutdown Pin Voltage.”
Q11
+
Q2
Q12
– 0.8V). See the Typical Performance Character-
Q13
R4
40k
Q14
R5
40k
Q15
D3
Q3
Q16
–
Q17
Q18
V
Q19
OUT
–
LT1782
. When shut
Q20
Q22
Q21
–
V
1782 SS
or left
+
). In
9
V
OUT
V
+
–