SPM and Security Subsystem
FX651
1.4
External Components
Component
C1, C2
R1, R3
R2, R4
C3, C4
R5
C5
3.3V
33pF ±10%
1.1MΩ ±1%
270kΩ ±1%
0.1µF ±20%
51kΩ ±1%
100pF ±10%
5.0V
68pF ±10%
1.0MΩ ±1%
330kΩ ±1%
Notes
1. The device's sensitivity is approximately proportional to its power supply (V
DD
) voltage. The input
gain must compensate for this and also prevent the input circuitry saturating. It is recommended
that the amplifier components (R1 to R4, C1 and C2) are used to set the gain between -10dB (if
V
DD
is 5.0V) and -13dB (if V
DD
is 3.3V).
Figure 2 Recommended External Components (D4)
©
1997 Consumer Microcircuits Limited
6
D/651/4