TMS320 SECOND-GENERATION

DEVICES

SPRS010B Ð MAY 1987 Ð REVISED NOVEMBER 1990

TYPICAL SUPPLY CURRENT CHARACTERISTICS FOR TMS320C25

ICC vs f(CLKIN) and VCC

ICC vs f(CLKIN) and VCC

Normal Operating Mode

Powerdown Mode

ICC, mA

170

160TA = 25°C

140

130

120

110

100

90

80

70

60

50

40

30

20

10

48 12 16 20 24 28 32 36 40 44 48 52 f(CLKIN), MHz

VCC = 5.50 V VCC = 5.25 V VCC = 5.00 V VCC = 4.75 V VCC = 4.50 V

ICC, mA

80

70

60

50

40

30

20

10

0

48 12 16 20 24 28 32 36 40 44 48 52 f(CLKIN), MHz

VCC = 5.50 V VCC = 5.25 V VCC = 5.00 V VCC = 4.75 V VCC = 4.50 V

ADVANCE INFORMATION

TMS320C25FNL (PLCC) reflow soldering precautions

Recent tests have identified an industry-wide problem experienced by surface mounted devices exposed to reflow soldering temperatures. This problem involves a package cracking phenomenon sometimes experienced by large (e.g., 68-lead) plastic leaded chip carrier (PLCC) packages during surface mount manufacturing. This phenomenon occur if the TMS320C25FNL is exposed to uncontrolled levels of humidity prior to reflow solder. This moisture can flash to steam during solder reflow, causing sufficient stress to crack the package and compromise device integrity. If the TMS320C25FNL is being socketed, no special handling precautions are required. In addition, once the device is soldered into the board, no special handling precautions are required.

In order to minimize moisture absorption, TI ships the TMS320C25FNL in ªdry packº shipping bags with a RH indicator card and moisture-absorbing desiccant. These moisture-barrier shipping bags will adequately block moisture transmission to allow shelf storage for 12 months from date of seal when stored at less than 60% relative humidity (RH) and less than 30°C. Devices may be stored outside the sealed bags indefinitely if stored at less than 25% RH and 30°C.

Once the bag seal is broken, the devices should be stored at less than 60% RH and 30°C as well as reflow soldered within two days of removal. In the event that either of the above conditions is not met, TI recommends these devices be baked in a clean oven at 125°C and 10% maximum RH for 24 hours. This restores the devices to their ªdry packedº moisture level.

NOTE

Shipping tubes will not withstand the 125°C baking process. Devices should be transferred to a metal tray or tube be- fore baking. Standard ESD precautions should be followed.

In addition, TI recommends that the reflow process not exceed two solder cycles and the temperature not exceed 220°C.

If you have any additional questions or concerns, please contact your local TI representative.

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Texas Instruments Typical Supply Current Characteristics for TMS320C25, TMS320C25FNL Plcc reflow soldering precautions