LT1360 Linear Technology, LT1360 Datasheet - Page 11

• Manufacturer Part Number: LT1360
• Description: 50MHz/ 800V/us Op Amp
• Manufacturer: Linear Technology

APPLICATIONS
Input Considerations
Each of the LT1360 inputs is the base of an NPN and a PNP
transistor whose base currents are of opposite polarity
and provide first-order bias current cancellation. Because
of variation in the matching of NPN and PNP beta, the
polarity of the input bias current can be positive or nega-
tive. The offset current does not depend on NPN/PNP beta
matching and is well controlled. The use of balanced
source resistance at each input is recommended for
applications where DC accuracy must be maximized.
The inputs can withstand transient differential input volt-
ages up to 10V without damage and need no clamping or
source resistance for protection. Differential inputs, how-
ever, generate large supply currents (tens of mA) as
required for high slew rates. If the device is used with
sustained differential inputs, the average supply current
will increase, excessive power dissipation will result and
the part may be damaged. The part should not be used as
a comparator, peak detector or other open-loop applica-
tion with large, sustained differential inputs. Under
normal, closed-loop operation, an increase of power dis-
sipation is only noticeable in applications with large slewing
outputs and is proportional to the magnitude of the
differential input voltage and the percent of the time that
the inputs are apart. Measure the average supply current
for the application in order to calculate the power dissipa-
tion.
U
INFORMATION
U
W
U
Power Dissipation
The LT1360 combines high speed and large output drive
in a small package. Because of the wide supply voltage
range, it is possible to exceed the maximum junction
temperature under certain conditions. Maximum junction
temperature (T
ture (T
Worst case power dissipation occurs at the maximum
supply current and when the output voltage is at 1/2 of
either supply voltage (or the maximum swing if less than
1/2 supply voltage). Therefore P
Example: LT1360CS8 at 70 C, V
LT1360CN8: T
LT1360CS8: T
P
P
T
JMAX
DMAX
DMAX
A
) and power dissipation (P
= 70 C + (399mW)(190 C/W) = 146 C
= (V
= (30V)(5.8mA) + (7.5V)
+
J
– V
) is calculated from the ambient tempera-
J
J
= T
= T
–
)(I
A
A
SMAX
+ (P
+ (P
) + (V
D
D
x 190 C/W)
x 130 C/W)
DMAX
S
+
/2)
= 15V, R
D
2
/250W = 399mW
) as follows:
2
is:
/R
L
L
LT1360
= 250W
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