ISL76627 Datasheet, PDF (10/18 Pages) Intersil Corporation – Precision Low Noise Operational Amplifier

ISL76627
Typical Performance Curves V_S = ±15V, V_CM = 0V, R_L = Open, unless otherwise specified. (Continued)
90
80
V_S = ±15V
R_L = 10k
70 ^{AV = 1}
V_OUT = 100mV_P-P
60
50
40
30
20
OVERSHOOT ⁺
OVERSHOOT ^-
10
0
10
100
1000
10000
CAPACITANCE (pF)
FIGURE 27. % OVERSHOOT vs LOAD CAPACITANCE, V_S = ±15V
Applications Information
Functional Description
The ISL76627 is a single, low noise 10MHz BW precision op amp.
The device is fabricated in a new precision 40V complementary
bipolar DI process. A super-beta NPN input stage with input bias
current cancellation provides low input bias current (1nA typical),
low input offset voltage (10µV typ), low input noise voltage
(3nV/√Hz), and low 1/f noise corner frequency (5Hz). The
amplifier also features high open loop gain (1500V/mV) for
excellent CMRR (120dB) and THD+N performance (0.0002% @
3.5V_RMS, 1kHz into 2kΩ). A complementary bipolar output stage
enables high capacitive load drive without external
compensation.
Operating Voltage Range
The device is designed to operate over the 4.5V (±2.25V) to 40V
(±20V) range and are fully characterized at 10V (±5V) and 30V
(±15V). Parameter variation with operating voltage is shown in
the “Typical Performance Curves” beginning on page 6.
Input ESD Diode Protection
The input terminals (IN+ and IN-) have internal ESD protection
diodes to the positive and negative supply rails, and an additional
anti-parallel diode pair across the inputs (see Figures 28 and 29).
• The amplifier input is supplied from a low impedance source.
• The input voltage rate-of-rise (dV/dt) exceeds the maximum
slew rate of the amplifier (±3.6V/µs).
If the output lags far enough behind the input, the anti-parallel
input diodes can conduct. For example, if an input pulse ramps
from 0V to +10V in 1µs, then the output of the ISL76627 will reach
only +3.6V (slew rate = 3.6V/µs), while the input is at 10V. The
input differential voltage of 6.4V will force input ESD diodes to
conduct, dumping the input current directly into the output stage
and the load. The resulting current flow can cause permanent
damage to the ESD diodes. The ESD diodes are rated to 20mA,
and in the previous example, setting R_IN to 1k resistor (see
Figure 28) would limit the current to < 6.4mA, and provide
additional protection up to ±20V at the input.
In applications where one or both amplifier input terminals are at
risk of exposure to high voltage, current limiting resistors may be
needed at each input terminal (see Figure 29 R_IN+, R_IN-) to limit
current through the power supply ESD diodes to 20mA.
V_IN-
V_IN+
V+
R_IN-
-
R_IN+
+
V_OUT
R_L
V+
V-
-
V_IN
R_IN
+
V_OUT
R_L
V-
FIGURE 28. INPUT ESD DIODE CURRENT LIMITING- UNITY GAIN
For unity gain applications (see Figure 28) where the output is
connected directly to the non-inverting input, a current limiting
resistor (R_IN) will be needed under the following conditions to
protect the anti-parallel differential input protection diodes.
FIGURE 29. INPUT ESD DIODE CURRENT LIMITING - DIFFERENTIAL
INPUT
Output Current Limiting
The output current is internally limited to approximately ±45mA
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.
10
FN7725.0
July 12, 2011