LT1803 LINER [Linear Technology], LT1803 Datasheet - Page 14

• Manufacturer Part Number: LT1803
• Description: Single/Dual/Quad 100V/ms, 85MHz, Rail-to-Rail Input and Output Op Amps
• Manufacturer: LINER [Linear Technology]

LT1803/LT1804/LT1805
APPLICATIO S I FOR ATIO
If both amplifiers are loaded simultaneously, then the total
power dissipation is 0.19W.
The maximum ambient temperature that the part is al-
lowed to operate is:
Similar calculations can be carried out for specific pack-
ages and conditions.
Also worth noting, the DD package includes a low
underside metal which is internally connected to V
underside metal is properly soldered to a PCB, the
the part will be close to 50 C/W. This
less than leaving the underside metal unattached and can
be useful for certain applications.
Input Offset Voltage
The input offset voltage will change greatly based upon
which input stage is active. The PNP input stage is active
from the negative supply voltage to about 1.3V below the
positive supply rail, then the NPN input stage is activated
for the remaining input range up to the positive supply rail
during which the PNP stage remains inactive. The offset
14
V
V
T
+
–
A
Q16
+
= T
= 150 C – (0.190W • 190 C/W) = 113.9 C
I
J
2
– (P
+IN
–IN
Q17
DMAX
U
Q18
• 190 C/W)
ESDD1
ESDD4
U
V
V
+
–
V
V
–
+
Figure 1. LT1803/LT1804/LT1805 Simplified Schematic Diagram
ESDD2
ESDD3
W
D6
D5
JA
D8
D7
Q19
is significantly
U
Q4
Q7
S
D1
D2
–
Q3
. If the
JA
JA
of
Q5
Q6
voltage is typically less than 1000 V in the range the PNP
input stage is active.
Input Bias Current
The LT1803/LT1804/LT1805 employ a patent-pending
technique to reduce the input bias current to less than 1 A
for the input common mode voltage range of 0.2V above
the negative supply rail to 1.75V below the positive rail.
The low input offset voltage and low input bias current
provide precision performance in high source impedance
applications.
Output
The LT1803/LT1804/LT1805 can deliver a large output
current, so the short-circuit current limit is set around
50mA to prevent damage to the device. Attention must be
paid to keep the junction temperature of the IC below the
absolute maximum rating of 150 C (refer to the Power
Dissipation section) when the output is continuously short
circuited. The output of the amplifier has reverse-biased
diodes connected to each supply. If the output is forced
beyond either supply, unlimited current will flow through
these diodes. If the current is transient and limited to less
than 100mA and the total supply voltage is less than
V
BIAS
Q1
+
D3
D4
Q2
I
1
Q10
Q11
Q9
R3
R1
Q12
Q8
R2
R4
C
C
+
V
OUTPUT BIAS
Q13
–
R5
BUFFER
I
3
AND
C2
C1
180345 F01
Q15
Q14
180345f
OUT