VRE107

VRE107DS

3

P r o d u c t I n n o v a t i o n F r o m

VRE107M

VRE107MA

QUIESCENT CURRENT VS. TEMP

JUNCTION TEMP. RISE VS. OUTPUT CURRENT

Output Current (mA)

PSRR VS. FREQUENCY

Frequency (Hz)

POSITIVE OUTPUT

NEGATIVE OUTPUT

QUIESCENT CURRENT VS. TEMP

JUNCTION TEMP. RISE VS. OUTPUT CURRENT

Output Current (mA)

PSRR VS. FREQUENCY

Frequency (Hz)

-0.7

0.7

-0.6

0.6

TYPICAL PERFORMANCE GRAPHS

2. THEORY OF OPERATION

The following discussion refers to the block diagram in Figure 1. A FET current source is used to bias a 6.3 V zener

diode. The zener voltage is divided by the resistor network R1 and R2. This voltage is then applied to the noninvert-

ing input of the operational amplifier which amplifies the voltage to produce a 5 V output. The gain is determined by

the resistor networks R3 and R4: G=1 + R4/R3. The 6.3 V zener diode is used because it is the most stable diode

over time and temperature.

The current source provides a closely regulated zener current, which determines the slope of the reference’s volt-

age vs. temperature function. By trimming the zener current, a lower drift over temperature can be achieved. But

since the voltage vs. temperature function is nonlinear, this method leaves a residual error over wide temperature

ranges.

To remove this residual error, a nonlinear compensation network of thermistors and resistors is used in the VRE107