ISL28134_1107 Datasheet, PDF (13/24 Pages) Intersil Corporation – 5V Ultra Low Noise, Zero Drift Rail-to-Rail Precision Op Amp

ISL28134
Typical Performance Curves T_A =+25°C, V_CM = 0V Unless otherwise specified. (Continued)
1.2
1.0
0.8
INPUT
0.10
0.08
0.06
OUTPUT
0.6
0.4
OUTPUT
0.2
0
0
V_s = 5V_DC
A_V = 1V
R_L = 100k
V_IN = 0.1V to 1.1V
2
4
6
8
10
TIME (µs)
FIGURE 39. LARGE SIGNAL STEP RESPONSE (1V)
60
55
50
- OS
45
40
+OS
35
30
25
20
15
10
10
V_s = ±2.5V
A_V = 1V
R_L = 100k
V_OUT = 100mVpp
100
LOAD CAPACITANCE (pF)
1000
FIGURE 41. SMALL SIGNAL OVERSHOOT vs LOAD CAPACITANCE,
Vs = ±2.5V
0.04
INPUT
0.02
0
-0.02
-0.04
0
V_s = ±2.5V_DC
A_V = 1V
R_L = 100k
V_IN = 0V to 0.1V
2
4
6
8
10
TIME (µs)
FIGURE 40. SMALL SIGNAL STEP RESPONSE (100mV)
55
50
45
- OS
40
35
+OS
30
25
20
V_s = ±1.25V
A_V = 1V
15
R_L = 100k
V_OUT = 100mVpp
10
10
100
1000
LOAD CAPACITANCE (pF)
FIGURE 42. SMALL SIGNAL OVERSHOOT vs LOAD CAPACITANCE,
Vs = ±1.25V
Applications Information
Functional Description
The ISL28134 is a single 5V rail-to-rail input/output amplifier
that operates on a single or dual supply. The ISL28134 uses a
proprietary chopper-stabilized technique that combines a 3.5MHz
main amplifier with a very high open loop gain (174dB) chopper
amplifier to achieve very low offset voltage and drift (0.2µV,
0.5nV/°C) while having a low supply current (675µA). The very low
1/f noise corner <0.1Hz and low input noise voltage (8nV/√Hz @
100Hz) of the amplifier makes it ideal for low frequency precision
applications requiring very high gain and low noise.
This multi-path amplifier architecture contains a time continuous
main amplifier whose input DC offset is corrected by a
parallel-connected, high gain chopper stabilized DC correction
amplifier operating at 100kHz. From DC to ~10kHz, both
amplifiers are active with the DC offset correction active with
most of the low frequency gain provided by the chopper
amplifier. A 10kHz crossover filter cuts off the low frequency
chopper amplifier path leaving the main amplifier active out to
the -3dB frequency (3.5MHz GBWP).
The key benefits of this architecture for precision applications are
rail-to-rail inputs/outputs, high open loop gain, low DC offset and
temperature drift, low 1/f noise corner and low input noise
voltage. The noise is virtually flat across the frequency range
from a few mHz out to 100kHz, except for the narrow noise peak
at the amplifier crossover frequency (10kHz).
Power Supply Considerations
The ISL28134 features a wide supply voltage operating range. The
ISL28134 operates on single (+2.25V to +6.0V) or dual (±1.125 to
±3.0V) supplies. Power supply voltages greater than the +6.5V
absolute maximum (specified in the “Absolute Maximum Ratings”
on page 4) can permanently damage the device. Performance of
the device is optimized for supply voltages greater than 2.5V. This
makes the ISL28134 ideal for portable 3V battery applications that
require the precision performance. It is highly recommended that a
0.01µF or larger high frequency decoupling capacitor is placed
across the power supply pins of the IC to maintain high performance
of the amplifier.
13
FN6957.2
July 25, 2011