iC-GF
TRANSCEIVER
Rev C1, Page 22/26
APPLICATION NOTES
VCC
Setup for medium and small currents at VCC/VCC3
For medium output currents at VCC/VCC3 the induc-
tor of the switching converter may as well be replaced
by a resistor (see Fig. 14), resulting though in a con-
siderably less efficiency (power dissipation!) and an
elevated noise level at VH and thus at VCC/VCC3.
VCC3
CVCC
1uF
CVCC3
1uF
VCC3
VCC VBR
NUVD/MISO
Status
Output
Undervoltage
NOVL/NDIAG
Toff
1
CVH
1uF
Overload
RSET
ISET
VHR
170
CVBR
1uF
..10mA
VH
8.2K
VCC3
Channel 1
VCC3
VCC3
VCC
VHL
VBR
VCC3
CEM1
QCFG1/NCS
INV1/ESPI
100pF
SENSOR
VBO
VBO
DC/DC
Converter
CEM2
100pF
IN1/TX
VBO < VN
CVBO
100nF
Lin. Regulator
Bias
Input Interface
VCC3
Channel 2
QCFG2/SCLK
Figure 14: LVH replaced by a resistor
IN2/MOSI
OEN
For small output currents the switching converter can
be bypassed completely (see Fig. 15).
Figure 16: SPI Mode in extremely noisy environ-
ments
CVBR
1uF
..50mA
VCC3
VCC
VH
VHL
Output protection
Figures 17 to 20 show some common configurations
with different wire counts and the respective additional
protective circuitry against transients on the transmis-
sion line; suggested values as follows:
VBO
VBO
DC/DC
Converter
VBO < VN
CVBO
100nF
Lin. Regulator
Bias
CQx:
1 nF
1 nF
100 nF
Figure 15: Switching converter bypassed
CCFI:
CVBO:
TVSx:
In extremely noisy environments, additional blocking
capacitors (CEM1, CEM2) can be used to ensure SPI
mode (see Fig. 16).
TVS diodes (eg. Vishay GSOT36C)
ICHAUS [ IC-HAUS GMBH ]
