The on−chip 6.25 V regulator (Pin 7) provides charging current for the oscillator timing capacitor, a reference for the Error Amplifier, and can supply 20 mA of current suitable
for directly powering sensors in low voltage applications. In higher voltage applications it may become necessary to transfer the power dissipated by the regulator off the IC. This
is easily accomplished with the addition of an external pass transistor as shown in Figure 22. A 6.25 V reference level was chosen to allow implementation of the simpler NPN circuit, where Vref − VBE exceeds the minimum voltage required by Hall Effect sensors over temperature. With proper transistor selection, and adequate heatsinking, up to one amp of load current can be obtained.