TCA505BG Datasheet, PDF (17/18 Pages) Siemens Semiconductor Group – IC for Inductive Proximity Switches with Short-Circuit Protection

TCA 505 BG
Application Circuit 3
Output Circuitry (Use of pins VREF, B, SC, Q1 through Q4, CD)
N-switch, short-circuit-proof, LED indicator, configurable as normally closed or
normally open
Short-circuit-current sampling:
0.3 V
RSC =
max. load current
Constant base current: ¹⁾
2V
RQ =
max. base current + IRR
For dimensioning of CD see characteristics. CD is usually between 1 and 10 nF. Filtering of
VREF is for noise immunity. CREF can be 10 nF for example. RREF serves for discharging residual
current of outputs Q2, 4.
1) _{When IQ > 10 mA, a resistor RREF on pin VREF will improve the constant current operation.}
Semiconductor Group
17