ATA5278 ATMEL Corporation, ATA5278 Datasheet - Page 21

• Manufacturer Part Number: ATA5278
• Description: Stand-alone Antenna Driver
• Manufacturer: ATMEL Corporation

Figure 3-15. Fault Shutdown Timing
3.17
4832D–RKE–12/07
MODACTIVE pin
Boost converter
Driver output
Internal fault
CLKO Output Pin
QSC gate
operation
signal
signal
stage
Note: Internal fault signal rises as soon as a fault (overtemperature, short circuit or open load) is detected
Figure 3-15
active. If a critical condition persists for a time shorter than the debouncing time (e.g., caused by
interferences), no shutdown will occur.
The diagnosis bits are based in the status register and are encoded as shown in
Table 3-4.
The clock output pin CLKO of the ATA5278 can be used to supply an on-board microcontroller
with a clock signal (either 4 MHz or 8 MHz). This signal is not suited to supply any device
beyond the PCB boundaries.
The clock signal is directly derived from the clock source connected to the OSCI/OSCO pins of
the ATA5278 and is available as long as the ATA5278 is not in power-down mode. The fre-
quency can be selected with the prescaler (PS) bit in configuration register 2, which is 0 for the
full-clock rate (f
t < t
Bit Position
X
deb,min
7 (MSB)
0 (LSB)
1
2
3
4
5
6
shows the sequence of a fault shutdown during the antenna driver-stage being
Diagnosis Bits (Status Register)
CLKO
Bit Name
= f
SH
CH
OT
OL
SL
IC
-
-
OSCI
) or 1 for the half clock-rate (f
Fault Type
Overtemperature detected
Antenna driver output pin has overload to Ground
Antenna driver output pin has overload to VDS (VBATT)
Open load detected (no oscillation at VSHUNT pin)
Overcurrent at antenna return line (QSC drain input) detected
Illegal command in the SPI input register found
Not defined
Not defined
t > t
1
X
1
1
1
deb,min
CLKO
= f
OSCI
/2).
Fault is latched in status
register afterwards
ATA5278
Table
Z
0
0
0
3-4.
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