x45620 Intersil Corporation, x45620 Datasheet - Page 11

• Manufacturer Part Number: x45620
• Description: Dual Voltage Monitor With Integrated System Battery Switch And Eeprom
• Manufacturer: Intersil Corporation

System Battery Switch
As long as V
old V
(typical) switch. When the V
then V
greater than V
than V
through an 80Ω (typical) switch. V
plies the system static RAM voltage, so the switchover
circuit operates to protect the contents of the static
RAM during a power failure. Typically, when V
failed, the SRAMs go into a lower power state and
draw much less current than in their active mode.
When V
V
sis around this battery switch threshold to prevent
oscillations between supplies.
While V
pulled LOW. The signal can drive external pass ele-
ments to provide additional current to the external cir-
cuits during normal operation.
Figure 2. Example System Connection
CC
exceeds V
TRIP1
BATT
Unregulated
V2MON
Provides
Early Detection
of Power Failure
CC
CC
CC
Supply
, V
is applied to V
is connected to V
returns, V
- 0.03V, then V
CC
OUT
BATT
BATT
exceeds the low voltage detect thresh-
is connected to V
+ 0.03V. When V
+0.03V. There is a 60mV hystere-
OUT
11
switches back to V
OUT
OUT
CC
OUT
Supercap
Reg
5V
has fallen below V
if V
is connected to V
the BATT-ON pin is
CC
OUT
CC
CC
+
is equal to or
through a 5Ω
typically sup-
drops to less
CC
CC
V
V
V2MON
V
when
CC
BATT
SS
TRIP
BATT
has
SDA, SCL
BATT-ON
X45620
,
V2FAIL
RESET
Dual P-channel FET
Examples: IRF 7756, FDS9733A
V
OUT
Operation
The device is in normal operation with V
V
when V
Manual Reset
By connecting a push-button from MR to ground or
driven by logic, the designer adds manual system reset
capability. The RESET pins is asserted when the push-
button is closed and remain asserted for t
push-button is released. This pin is debounced so a
push-button connected directly to the device will have
both clean falling and rising edges on MR.
V
V
V
0 ≤ V
and V
CC
CC
CC
BATT
Condition
> V
> V
> V
CC
CC
CC
= 0
TRIP1
TRIP1
TRIP1
< V
< V
goes away.
TRIP1
Enable
BATT
. It switches to the battery backup mode
&
Address
Decode
Normal Operation.
Normal Operation without battery
back up capability.
Battery Backup Mode; RESET
signal is asserted. No communica-
tion to the device is allowed.
NMI
RESET
2-Wire µC
SRAM
Mode of Operation
Addr
V
CC
PURST
CC
as long as
July 29, 2005
after the
FN8250.0