APPLICATION NOTE 5756

How to Replace a DS1216 SmartSocket with an Equivalent-Density Phantom Clock Module


Abstract: With the diminishing availability of plastic dual-in-line package (PDIP) static random access memory (SRAMs), the DS1216 SmartWatch products are rapidly approaching end-of-life. Most of the SmartWatch products can be replaced using a pin-compatible, equivalent-density 5V Phantom clock module. This replacement module provides the customer with a drop-in, one-piece solution with an expected data retention life of at least 10 years.

With the diminishing availability of plastic dual-in-line package (PDIP) static random access memory (SRAMs), the DS1216 SmartWatch products are rapidly approaching end-of-life. Populating new sockets with low-power memory devices has already become a procurement challenge that can be easily avoided.
As shown in Table 1, most of the SmartWatch products can be replaced using a pin-compatible, equivalent-density 5V Phantom clock module. This provides the customer with a drop-in, one-piece solution that is guaranteed to at least 10 years of data retention life.1
In existing applications, a DS1216 SmartWatch and some version of a customer-procured SRAM provide the nonvolatile memory functionality for data storage in the absence of external power. The SRAM is the load that eventually consumes the internal battery’s charge capacity. Without knowing how much current that SRAM is actually consuming, when you arbitrarily move that SRAM to the new socket, the life expectancy of that new socket becomes unknown. The dead battery in the old DS1216 socket was merely a symptom of the problem, but the root cause (SRAM) is now transferred to a new socket to fail again in time.
The SRAM specification is a good reference for identification of the memory density, as well as the memory performance-based information to determine which speed grade of module to purchase. The customer should initially research the presently installed memory component and refer to Table 1 to select an appropriate replacement. ROM-based products (DS1216E and DS1216F) have no known replacements.
Table 1. SmartWatch Replacement Products
SmartWatch SRAM Density/Configuration Drop-In Replacement
Phantom Clock Module
DS1216B 16kb/2k x 8 Not available
64kb/8k x 8 DS1243Y-120+
DS1216C 64kb/8k x 8 DS1243Y-120+
256kb/32k x 8 DS1244Y-70+
DS1216D 256kb/32k x 8 DS1244Y-70+
1Mb/128k x 8 DS1248Y-70+
DS1216H 1Mb/128k x 8 DS1248Y-70+
4Mb/512k x 8 DS1251Y-70+
DS1216 SmartWatch components are rated for 0°C to +70°C operation, which is matched by the DS12xx-family of commercial-temperature products. If desired, industrial temperature range (-40°C to +85°C) module products, designated as “IND”, are also available in any Phantom clock module density. Refer to the ordering information for that specific module product.
DS1216 SmartWatch products are manufactured using TinLead solder (SnPb 63/37) to attach the internal components. If desired, Pb-free/RoHS-compliant (100% Matte Tin) module products, designated by a plus sign (“+”), are also available in every memory density except 16kb. Refer to the ordering information for that specific module product.
Due to the internal battery, neither the DS1216 SmartWatch, nor any listed DS12xx-family of Phantom clock modules can tolerate convection reflow soldering. Wave or hand soldering is acceptable. Or, alternatively, install the module component into a socket.
For additional technical literature see Maxim’s SmartWatch or Phantom Clock Module products.
Notes:
  1. DS1216 tDR (Timekeeping and Memory Data Retention Life) may achieve up to 10 years if the customer’s SRAM load is below 0.5µA
  2. DS1243Y-120+ tDR (Timekeeping and Memory Data Retention Life) will achieve at least 10 years.


Related Parts
DS1216 SmartWatch RAM DS1216B/C/D/H
SmartWatch ROM DS1216E/F
 
DS1243 64K NV SRAM with Phantom Clock Free Samples  
DS1244 256k NV SRAM with Phantom Clock Free Samples  
DS1248 1024K NV SRAM with Phantom Clock Free Samples  
DS1251 4096K NV SRAM with Phantom Clock Free Samples  


Next Steps
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© Oct 01, 2013, Maxim Integrated Products, Inc.
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APP 5756: Oct 01, 2013
APPLICATION NOTE 5756, AN5756, AN 5756, APP5756, Appnote5756, Appnote 5756