LT1413ACN8#PBF Linear Technology, LT1413ACN8#PBF Datasheet - Page 7

• Manufacturer Part Number: LT1413ACN8#PBF
• Description: IC PRECISION OP-AMP DUAL 8-DIP
• Manufacturer: Linear Technology

Specifications of LT1413ACN8#PBF

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Slew Rate: 0.4 V/µs
• Gain Bandwidth Product: 950kHz
• Current - Input Bias: 8nA
• Voltage - Input Offset: 75µV
• Current - Supply: 350µA
• Voltage - Supply, Single/dual (±): 2.85 V ~ 36 V, ±1.425 V ~ 18 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Current - Output / Channel: -
• -3db Bandwidth: -

APPLICATIONS
Single Supply Operation
The LT1413 is fully specified for single supply operation,
i.e., when the negative supply is 0V. Input common-mode
range includes ground; the output swings within a few
millivolts of ground.
If the input is more than a few hundred millivolts below
ground, two distinct problems can occur on previous
single supply designs, such as the LM124, LM158, OP-21
and OP-221.
a) When the input is more than a diode drop below
ground, unlimited current will flow from the substrate
(V
the LT1413, the 400 resistors, in series with the input
(see Schematic Diagram), protect the devices even when
the input is 5V below ground.
b) When the input is more than 400mV below ground
(at 25 C), the input stage saturates (transistors Q3 and
Q4) and phase reversal occurs at the output. This can
cause lock-up in servo systems. Due to a unique phase
reversal protection circuitry (Q21, Q22, Q27, Q28), the
LT1413 outputs do not reverse, as illustrated below,
even when the inputs are at –1.5V. Keep the output of the
–
4V
2V
0V
terminal) to the input. This can destroy the unit. On
6V
P-P
INPUT, –1.5V TO 4.5V
–100
4
2
0
0
Comparator Rise Response Time
10mV, 5mV, 2mV Overdrives
U
V
S
= 5V, 0V
INFORMATION
Voltage Follower with Input Exceeding the Negative Common-Mode Range
U
LT1413 • TA21
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
W
4V
2V
0V
50 s/DIV
EXHIBIT OUTPUT PHASE REVERSAL
LT1413 • TA24
U
LM324, LM358, OP-221
other amplifier out of negative saturation for the phase
reversal protection to function properly.
Since the output of the LT1413 cannot go exactly to
ground, but can only approach ground to within a few
millivolts, care should be exercised to ensure that the
output is not saturated. For example, a 1mV input signal
will cause the amplifier to set up in its linear region
in the gain 100 configuration shown below, but is not
enough to make the amplifier function properly in the
voltage-follower mode.
Comparator Applications
The single supply operation of the LT1413 lends itself to
its use as a precision comparator with TTL compatible
output; the response time is shown below.
R
100
1mV
4
2
0
0
Gain 100 Amplifier
Comparator Fall Response Time
to 10mV, 5mV, 2mV Overdrives
LT1413 • TA22
–
+
V
S
= 5V, 0V
5V
Figure 1.
99R
4V
2V
0V
100mV
1mV
50 s/DIV
Voltage Follower
–
+
LT1413 • TA25
NO PHASE REVERSAL
5V
LT1413
LT1413
OUTPUT
SATURATED
15mV
LT1413 • TA23
LT1413 • 27
7