MAT02 Analog Devices, Inc., MAT02 Datasheet - Page 11

• Manufacturer Part Number: MAT02
• Description: Low Noise, Matched Dual Monolithic Transistor
• Manufacturer: Analog Devices, Inc.

Transistors Q2 and Q3 form a 2 mA current source (0.65 V/
330 Ω ~ 2 mA). Each collector of Q1 operates at 1 mA. The
OP184 inputs are 3 V below the positive supply voltage (R
~ 3 V). Input stage gain is g
when operating at I
OP184 has a minimum open-loop gain of 500,000, total
open-loop gain for the composite amplifier is over 50 million.
Even at closed-loop gain of 1000, the gain error due to finite
open-loop gain will be negligible. The OP184 features excellent
symmetry of slew-rate and very linear gain. Signal distortion is
minimal.
Dynamic range of this amplifier is excellent; the OP184 has an
output voltage swing of ± 14.8 V with a ± 15 V supply.
Input characteristics are outstanding. The MAT02F has offset
voltage of less than 150 µV at 25°C and a maximum offset drift
of 1 µV/°C. Nulling the offset will further reduce offset drift.
This can be accomplished by slightly unbalancing the collector
load resistors. This adjustment will reduce the drift to less than
0.1 µV/°C.
REV. E
C
of 1 mA with R
m
R
L
, which is approximately 100
L
of 3 kΩ. Since the
L
I
C
–11–
Input bias current is relatively low due to the high current gain
of the MAT02. The minimum β of 400 at 1 mA for the
MAT02F implies an input bias current of approximately 2.5 µA.
This circuit should be used with signals having relatively low
source impedance. A high source impedance will degrade offset
and noise performance.
This circuit configuration provides exceptionally low input noise
voltage and low drift. Noise can be reduced even further by
raising the collector currents from 1 mA to 3 mA, but power
consumption is then increased.
MAT02