DS1210SN+ Maxim Integrated Products, DS1210SN+ Datasheet - Page 2

IC CNTRLR CHIP NV IND 16-SOIC

DS1210SN+

Manufacturer Part Number
DS1210SN+
Description
IC CNTRLR CHIP NV IND 16-SOIC
Manufacturer
Maxim Integrated Products
Datasheet

Specifications of DS1210SN+

Controller Type
Nonvolatile RAM
Voltage - Supply
4.75 V ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Package / Case
16-SOIC (0.300", 7.5mm Width)
Manual Reset
No
Watchdog
No
Battery Backup Switching
Yes
Supply Voltage (max)
5.5 V
Supply Voltage (min)
4.75 V
Supply Current (typ)
5 mA
Mounting Style
SMD/SMT
Maximum Operating Temperature
+ 85 C
Chip Enable Signals
Yes
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
OPERATION
The DS1210 nonvolatile controller performs five circuit functions required to battery back up a RAM.
First, a switch is provided to direct power from the battery or the incoming supply (V
which is greater. This switch has a voltage drop of less than 0.3V. The second function which the
nonvolatile controller provides is power-fail detection. The DS1210 constantly monitors the incoming
supply. When the supply goes out of tolerance a precision comparator detects power-fail and inhibits chip
enable (
within 0.2 volts of the V
the
the current memory cycle is completed prevents the corruption of data. Power-fail detection occurs in the
range of 4.75 volts to 4.5 volts with the tolerance Pin 3 grounded. If Pin 3 in connected to V
power-fail detection occurs in the range of 4.5 volts to 4.25 volts. During nominal supply conditions
performs is a battery status warning so that potential data loss is avoided. Each time that the circuit is
powered up the battery voltage is checked with a precision comparator. If the battery voltage is less than
2.0 volts, the second memory cycle is inhibited.
performing a read cycle after power-up to any location in memory, verifying that memory location
content. A subsequent write cycle can then be executed to the same memory location altering the data. If
the next read cycle fails to verify the written data, then the batteries are less than 2.0V and data is in
danger of being corrupted. The fifth function of the nonvolatile controller provides for battery
redundancy. In many applications, data integrity is paramount. In these applications it is often desirable to
use two batteries to ensure reliability. The DS1210 controller provides an internal isolation switch which
allows the connection of two batteries. During battery backup operation the battery with the highest
voltage is selected for use. If one battery should fail, the other will take over the load. The switch to a
redundant battery is transparent to circuit operation and to the user. A battery status warning will occur
when the battery in use falls below 2.0 volts. A grounded V
warning. In applications where battery redundancy is not required, a single battery should be connected to
the BAT1 pin. The BAT2 battery pin must be grounded. The nonvolatile controller contains circuitry to
turn off the battery backup. This is to maintain the battery(s) at its highest capacity until the equipment is
powered up and valid data is written to the SRAM. While in the freshness seal mode the
will be forced to V
provide battery back-up until V
Figure 1 shows a typical application incorporating the DS1210 in a microprocessor-based system. Section
A shows the connections necessary to write protect the RAM when V
up the supply with batteries. Section B shows the use of the DS1210 to halt the processor when V
less than 4.75 volts and to delay its restart on power-up to prevent spurious writes.
CEO
CEO
will follow
CEO
output is kept in its present state until
). The third function of write protection is accomplished by holding the
OL
CE
. When the batteries are first attached to one or both of the V
with a maximum propagation delay of 20ns. The fourth function the DS1210
CCI
or battery supply. If
CCI
exceeds V
CCTP
CE
, as set by the T
CE
2 of 6
is returned high. The delay of write protection until
input is low at the time power-fail detection occurs,
Battery status can, therefore, be determined by
BAT2
OL
pin, and then falls below V
CC
pin will not activate a battery-fail
is less than 4.75 volts and to back
BAT
CEO
pins, V
CCI
output signal to
) depending on
CEO
CCO
BAT
and V
CCO
.
will not
, then
CC
CCO
is

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