H6006 EMMICRO [EM Microelectronic - MARIN SA], H6006 Datasheet - Page 5

• Manufacturer Part Number: H6006
• Description: Failsafe Watchdog
• Manufacturer: EMMICRO [EM Microelectronic - MARIN SA]

Pin Description
Functional Description
Supply Lines
The circuit is powered through the V
monitors both its own V
V
V
During power-up the V
soon as V
depend on the watchdog timer and the volt-age at V
to the thresholds (see Fig. 3 and 4). If the supply voltage V
falls back below V
monitoring are disabled and the outputs SAVE and RES are
active low. The V
V
The analog voltage comparators compare the voltage applied
to V
with the stabilized supply voltage V
with the bandgap voltage (versions A3, B3) (see Fig. 7). At
power-up, when V
level, the SAVE output goes high, and the timer starts
running, setting RES high after the time T
falls below V
V
V
sequence. The RES output may however be influenced
independently of the voltage V
section “Combined Voltage and Timer Action”. Monitoring the
rough DC side of the regulator as shown in Fig. 12 is the only
way to have advanced warning at power-down. Spikes on V
should be filtered if they are likely to drop below V
The combination of V
system security: if V
device starts the power-on sequence only when V
V
be detected.
Voltage Thresholds on V
The H6006 is available with 3 different sets of thresholds :
Copyright © 2004, EM Microelectronic-Marin SA
SAVE stay active low as long as V
RES output will go low and the on-chip timer will stop. When
IN
DD
IN
IN
IN
ON
Pin
1
2
3
4
5
6
7
8
input.
rises again above V
Monitoring
rises again above V
Monitoring
IN
(Fig. 3). Short circuits on the regulated supply voltage can
(typically connected to the input of the voltage regulator)
Name
SAVE
RES
TCL
V
V
RC
DD
V
TO
DD
SS
IN
SL
reaches the V
R
, the SAVE output goes low and stays low until
DD
OFF
Function
Voltage monitoring input
Timer clear input signal
RC oscillator tuning input
GND terminal
Reset output
Save output
Timer output signal
Positive supply voltage terminal
DD
line should be free of spikes.
IN
(1.5 V) the watchdog timer and the V
reached V
IN
SH
rises much faster than V
DD
IN
monitoring is disabled and RES and
SH
. If V
IN
supply and a voltage applied to the
and V
, the timer will initiate a power-up
ON
IN
level, the state of the outputs
falls below the voltage V
ON
IN
DD
DD
DD
by the timer action, see
and V
monitoring provide high
is below V
(versions B1, A2, B2) or
DD
TO
IN
and V
(see Fig. 4). If V
reaches the V
ON
SL.
DD
(3.5 V). As
DD
SS
, then the
IN
Table 6
reached
relative
pins. It
RL
, the
DD
SH
IN
IN
IN
5
Version B1: with internal voltage divider, resulting in
thresholds for direct monitoring of the unregulated voltage
without external components.
Version A2, B2: for monitoring of all unregulated voltage,
where custom programming is required. Fixed resistor
values can be used for programming.
Version A3, B3: for monitoring of regulated voltage, where
no unregulated voltage is available (the tolerance is ± 10 %,
see Table 4. For tighter tolerances, trimming can be used,
see Fig. 10).
Note : the internal threshold levels are 2.25 / 2.00 / 1.75 V
Note:
5 V ± 10%
Note: the internal threshold levels are 2.00 / 1.95 / 1.90 V
any voltage
> 9 V
reference)
(thresholds dependent on the internal bandgap
at V
R
VIN
The threshold levels are 9/8/7 V normally.These
are divided internally by 4 to give internal thres-
holds of 2.25 / 2 / 1.75 V. V
dependent on V
= ~ 100 MΩ.
DD
Regulator
= 5 V (thresholds dependent on V
Voltage
Regulator
Voltage
R
VIN
= ~ 100 MΩ.
DD
). R
5 V
VIN
V
V
5 V
V
V
V
V
= ~ 100 kΩ.
IN
SS
IN
SS
IN
SS
DD
www.emmicroelectronic.com
= 5 V (thresholds
SAVE
H6006
SAVE
SAVE
DD
RES
RES
V
V
RES
V
DD
)
DD
DD
Fig. 9
Fig. 10
Fig. 8