isl28177 Intersil Corporation, isl28177 Datasheet - Page 7

• Manufacturer Part Number: isl28177
• Description: 40v General Purpose Precision Operational Amplifier
• Manufacturer: Intersil Corporation

Typical Performance Curves
Applications Information
Functional Description
The ISL28177 is a low noise op amp fabricated in a 40V
complementary bipolar DI process designed for general purpose
low power applications. It utilizes a super-beta NPN input stage
with input bias current cancellation for low input bias current and
low input noise voltage. A complimentary bipolar output stage
enables high capacitive load drive without external
compensation.
Operating Voltage Range
The ISL28177 is designed to operate over the 6V (±3V) to 40V
(±20V) range. The common mode input voltage range extends to
2V from each rail, and the output voltage swings to 1.3V of
each rail.
Input Performance
The super-beta NPN input pair reduces input bias current while
maintaining good frequency response, low input bias current and
low noise. Input bias cancellation circuits provide additional bias
current reduction to <1nA, and excellent temperature
stabilization and low TCV
Input ESD Diode Protection
The input terminals (IN+ and IN-) have internal ESD protection
diodes to the positive and negative supply rails, series connected
500Ω current limiting resistors and an anti-parallel diode pair
across the inputs (Figure 21).
-120
-160
-200
-240
-280
-40
-80
FIGURE 19. POSITIVE OUTPUT OVERLOAD RESPONSE TIME
80
40
0
0
40
80
120
OS
INPUT
160 200
OUTPUT
.
TIME (µs)
7
240
280 320
V
A
R
V
OVERDRIVE = 1V
S
V
IN
L
= ±15V
= 100
= 10k
= 200mV
360
P-P
V
400
S
ISL28177
16
14
12
10
8
6
4
2
0
-2
= ±15V, V
CM
The series resistors limit the high feed-through currents that can
occur in pulse applications when the input dv/dt exceeds the
0.2V/µs slew rate of the amplifier. Without the series resistors, the
input can forward-bias the anti-parallel diodes causing current to
flow to the output, resulting in severe distortion and possible diode
failure. Figure 17 provides an example of distortion free large signal
response using a 10V
The series resistors enable the input differential voltage to be equal
to the maximum power supply voltage (40V) without damage.
In applications where one or both amplifier input terminals are at
risk of exposure to high voltages beyond the power supply rails,
current limiting resistors may be needed at the input terminal to
limit the current through the power supply ESD diodes to
20mA max.
Output Current Limiting
The output current is internally limited to approximately ±30mA
at +25°C and can withstand a short circuit to either rail as long
as the power dissipation limits are not exceeded. Continuous
operation under these conditions may degrade long term
reliability.
Output Phase Reversal
Output phase reversal is a change of polarity in the amplifier
transfer function when the input voltage exceeds the supply
voltage. The ISL28177 is immune to output phase reversal.
= 0V, R
V
280
240
200
160
120
FIGURE 20. NEGATIVE OUTPUT OVERLOAD RESPONSE TIME
-40
-80
IN
80
40
0
L
0
FIGURE 21. INPUT ESD DIODE CURRENT LIMITING
= Open, unless otherwise specified. (Continued)
40
80
P-P
120
+
-
V-
V+
500Ω
input pulse with an input rise time of <1ns.
500Ω
OUTPUT
INPUT
160 200 240
TIME (µs)
280
V
A
R
V
OVERDRIVE = 1V
S
V
L
IN
= 100
= 10k
= ±15V
R
= 200mV
L
320
October 31, 2011
360
P-P
V
OUT
400
FN7859.0
2
0
-2
-4
-6
-8
-10
-12
-14
-16