DS1216B Maxim, DS1216B Datasheet - Page 13

• Manufacturer Part Number: DS1216B
• Description: The DS1216 SmartWatch RAM and SmartWatch ROM sockets are 600-mil-wide DIP sockets with a built-in CMOS watch function, an NV RAM controller circuit, and an embedded lithium energy source
• Manufacturer: Maxim

WARNING:
Under no circumstances should negative undershoots of any amplitude be allowed when the device is in
battery-backup mode. Water washing for flux removal will discharge internal lithium source because
exposed voltage pins are present.
NOTES:
1) Pin locations are designated “U” when a parameter definition refers to the socket receptacle and “L”
2) No memory inserted in the socket.
3) Pin 26L can be connected to V
4) SmartWatch sockets can be successfully processed through some conventional wave-soldering
5) t
6) V
7) Input pulse rise and fall times equal 10ns.
8) Applies to pins RST L, A2 L, A0 L, CE L, OE L, and WE L.
9) t
10) t
11) t
12) t
13) RST (Pin 1) has an internal pullup resistor.
14) Expected data retention is based on using an external SRAM with a data retention current of less than
15) The DS1216 products are shipped with the battery-backup power off. First power-up switches backup
when a parameter definition refers to the socket pin.
techniques as long as temperature exposure to the lithium energy source contained within does not
exceed +85°C. However, post-solder cleaning with water-washing techniques is not permissible.
Discharge to the lithium energy source can result, even if deionized water is used. It is equally
imperative that ultrasonic vibration is not used in order to avert damage to the quartz crystal resonator
employed by the oscillator circuit.
is the maximum voltage drop from V
0.5µA at +25°C. Expected data-retention time (time while on battery) for a given RAM battery
current can be calculated using the following formula:
battery on to clock and RAM V
CE
WR
DH
AS
AH
CCO
max must be met to ensure data integrity on power loss.
is a function of the first occurring edge of OE or CE.
and t
is a function of the latter occurring edge of OE or CE.
is a functions of the latter occurring edge of WE or CE.
1 is the maximum voltage drop from V
DS
are a function of the first occurring edge of WE or CE.
0.045 / (current in amps) = data-retention time in hours
CC
CC
or left disconnected at the PC board.
pin upon power-down.
BAT
to V
CC
CC
13 of 15
(L) to V
(U) while the part is in battery backup.
CC
(U) while Vcc(L) is supplying power. V
CCO
2