DS1213B ,SmartSocket 16k/64kPIN DESCRIPTIONCE - Conditioned Chip EnableV - Switched VCC CCGND - GroundAll pins pass through exc ..
DS1213C ,SmartSocket 256kFEATURES PIN ASSIGNMENT Accepts standard 32K x 8 CMOS static128 VCCRAMs2 27 Embedded lithium ..
DS1213-C ,SmartSocket 256kDS1213CSmartSocket 256kwww.dalsemi.com
DS1213D ,SmartSocket 256k/1MFEATURES PIN ASSIGNMENT Accepts standard 32K x 8 or 128K x 8132 VCCCMOS static RAMs2 31 Embed ..
DS1213D ,SmartSocket 256k/1MFEATURES PIN ASSIGNMENT Accepts standard 32K x 8 or 128K x 8132 VCCCMOS static RAMs2 31 Embed ..
DS1213-D ,SmartSocket 256k/1MDS1213DSmartSocket 256k/1Mwww.dalsemi.com
DTA114TM , Built-In Bias Resistors Enable The Configuration of An Inverter Circuit Without Connecting External Input Resistors
DTA114TS , DTA/DTC SERIES
DTA114TS , DTA/DTC SERIES
DTA114WE , -100mA / -50V Digital transistors (with built-in resistors)
DTA114WUA , -100mA / -50V Digital transistors (with built-in resistors)
DTA114YCA ,Conductor Holdings Limited - Digital Transistor
DS1213B
SmartSocket 16k/64k
FEATURESAccepts standard 2K x 8 or 8K x 8 CMOS
static RAMsEmbedded lithium energy cell retains RAM
dataSelf-contained circuitry safeguards dataData retention time is greater than 10 years
with proper RAM selectionIC socket permits upgrading from 2K x 8 to
8K RAMProven gas-tight socket contactsOperating temperature range 0°C to 70°C
PIN ASSIGNMENT
PIN DESCRIPTION- Conditioned Chip Enable
VCC - Switched VCC
GND - Ground
All pins pass through except 20, 26 and 28.
DESCRIPTIONThe DS1213B SmartSocket is a 28-pin, 600 mil DIP socket with a built-in CMOS controller circuit and
an embedded lithium energy source. It accepts either 24-pin 2K x 8 (lower-justified) or 28-pin 8K x 8
JEDEC bytewide CMOS static RAM. When the socket is mated with a CMOS RAM, it provides a
complete solution to problems associated with memory volatility. The Smart-Socket monitors incomingVCC for an out-of-tolerance condition. When such a condition occurs, the internal lithium energy source is
automatically switched on and write protection is unconditionally enabled to prevent data corruption.
Using the SmartSocket saves printed circuit board space since the SRAM/SmartSocket combination
occupies no more area than the SRAM alone. The SmartSocket modifies only pins 20, 26 and 28, tononvolatize the RAM. All other pins are passed straight through.
DS1213B
SmartSocket 16k/64k28-Pin Intelligent Socket
26 VCC3
28 VCC
20 CEGND 14
DS1213B
OPERATIONThe DS1213B SmartSocket performs five circuit functions required to battery back up a CMOS memory.
The first function involves switching between the battery and the VCC supply, depending on which is
greater. The switch has a voltage drop of less than 0.2 volts.
The second function is power-fail detection. The DS1213B constantly monitors the VCC supply. WhenVCC falls below 4.75 volts, a precision comparator detects the condition and inhibits the RAM chip
enable.
The third function, write protection, is accomplished by holding the RAM chip enable signal to within 0.2
volts of VCC or the battery supply whichever is greater. If the incoming chip enable signal is active at thetime power fail detection occurs, write protection is delayed until after the current memory cycle is
complete to avoid corruption of data. Power fail detection occurs in the range of 4.75 to 4.5 volts. During
nominal power supply conditions the chip enable signal will be passed through from the socket pin to the
socket contact with a maximum propagation delay of 20 ns.
The fourth function the DS1213B performs is to check battery status to warn of potential data loss. Each
time that VCC power is restored to the SmartSocket the battery voltage is checked with a precision
comparator. If the battery supply is less than 2.0 volts, the second memory access to the SmartSocket is
inhibited. Battery status can, therefore, be determined by a three-step process. First, a read cycle is
performed to any location in the memory, in order to save the contents of that location. A subsequentwrite 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 battery voltage is less than 2.0V and data is in danger of being
corrupted.
The fifth function the SmartSocket provides is battery redundancy. In many applications, data integrity isparamount. In these applications it is desirable to use two batteries to ensure reliability. The DS1213B
SmartSocket provides two batteries and an internal isolation switch to select between them. During
battery back up, the battery with the highest voltage is selected for use. If one battery fails, the other
automatically takes over. The switch between batteries is transparent to the user. A battery status warning
will occur if both batteries are less than 2.0 volts. Each of the two internal lithium cells has a 45 mAhcapacity.
NOTE:As shipped from Dallas Semiconductor, battery voltage cannot be measured on the VCC socket contact.
Only after VCC has been applied to the device for the first time and then removed will the battery voltage
be present on socket contacts 28, 26 and 20.
DS1213B
ABSOLUTE MAXIMUM RATINGS*Voltage on Any Pin Relative to Ground -0.3V to +7.0V
Operating Temperature 0°C to 70°C
Storage Temperature -40°C to +70°C
Soldering Temperature See J-STD-020A SpecificationThis is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS (0°°°°C to 70°°°°C)
DC ELECTRICAL CHARACTERISTICS (0°°°°C to 70°°°°C; VCC = 4.75 to 5.5V)
DC ELECTRICAL CHARACTERISTICS (0°°°°C to 70°°°°C; V
CC < 4.5V)
CAPACITANCE (TA = 25°°°°C)
DS1213B
AC ELECTRICAL CHARACTERISTICS (0°°°°C to 70°°°°C; VCC = 4.75 to 5.5V)
AC ELECTRICAL CHARACTERISTICS (0°°°°C to 70°°°°C; VCCI < 4.75 V)
TIMING DIAGRAM: POWER-DOWN
DS1213B
TIMING DIAGRAM: POWER-UP
WARNINGS:Under no circumstances are negative undershoots, of any amplitude, allowed when device is in batterybackup mode.
Water washing for flux removal will discharge internal lithium source because exposed voltage pins
are present.
NOTES:1. All voltages are referenced to ground.
2. Measured with a load as shown in Figure 1.
3. Pin locations are designated “U” (for upper) when a parameter definition refers to the socket
receptacle and “L” (for lower) when a parameter definition refers to the socket pin.
4. No memory inserted in the socket.
5. Pin 26 L may be connected to VCC or left disconnected at the PC board.
6. IBAT is the maximum load current which a correctly installed memory can use in the data retention
mode and meet data retention expectations of more than 10 years at 25°C.
7. tCE max. must be met to ensure data integrity on power loss.
8. VCC is within nominal limits and a memory is installed in the socket.
DS1213B
OUTPUT LOAD Figure 1
