VRE210_1 Datasheet, PDF (3/4 Pages) Cirrus Logic – Precision Voltage Reference

Product Innovation From
VRE210
2. TYPICAL PERFORMANCE CURVES
V_OUT vs. TEMPERATURE
V_OUT vs. TEMPERATURE
V_OUT vs. TEMPERATURE
V_OUT vs. TEMPERATURE
1.2
0.8
0.6
1.0
-0.6
-0.8
-1.0
-1.2
Temperature ^oC
VRE210C
Temperature ^oC
VRE210CA
Temperature ^oC
VRE210M
Temperature ^oC
VRE210MA
QUIESCENT CURRENT VS. TEMP JUNCTION TEMP. RISE VS. OUTPUT CURRENT
PSRR VS. FREQUENCY
Temperature ^oC
Output Current (mA)
Frequency (Hz)
3. THEORY OF OPERATION
The following discussion refers to the block diagram in Figure 1. In operation, approximately 6.3 volts is applied to
the noninverting input of the op amp. The voltage is amplified by the op amp to produce a 10 V output. The gain is
determined by the networks R1 and R2: G=1 + R2/R1. The 6.3V zener diode is used because it is the most stable
diode over time and temperature.
The zener operating current is derived from the regulated output voltage through R3. This feedback arrangement
provides a closely regulated zener current. This current determines the slope of the references’ voltage vs. tempera-
ture function. By trimming the zener current a lower drift over temperature can be achieved. But since the voltage
vs. temperature function is nonlinear this compensation technique is not well suited for wide temperature ranges.
A nonlinear compensation network of thermistors and resistors that is used in the VRE series voltage references.
This proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. By then adjust-
ing the slope, Thaler Corporation produces a very stable voltage over wide temperature ranges. This network is less
than 2% of the overall network resistance so it has a negligible effect on long term stability. By using highly stable
resistors in our network, we produce a voltage reference that also has very good long term stability.
VRE210DS
3