5

Recommended heat profile and reflow soldering

Figure 4. Reflow profile chart

Time

Critical Zone

Ramp-down

t 25°C to Peak

TL

TL to Tp

tp

Ramp-up

Tsmax

Tsmin

Tp

TL

25

ts

Preheat

IPC-020c-5-1

Note:

tp = 20-40 s, ramp-up = 3 °C/s max., tL = 60-150 s, ramp-down = 6 °C/s max., TL = 217 °C, TS max. = 200 °C,

TS min. = 150 °C, ts = 60 - 180 s, from Tj = 25 °C to peak = 8 minutes max., tp = see Table 7.

Table 7. Pb-free process - package classification reflow temperatures (1)

Package thickness

Volume mm3 < 350

Volume mm3 350-2000

Volume mm3 > 2000

< 1.6 mm

260 + 0 °C

260 + 0 °C

260 + 0 °C

1.6 mm - 2.5 mm

250 + 0 °C

245 + 0 °C

≥ 2.5 mm

250 + 0 °C

240 + 0 °C

1. Tolerance: the device manufacturer/supplier shall assure process compatibility up to and including the stated classification

temperature (this means peak reflow temperature + 0 °C. For example 260 °C + 0 °C) at the rated MSL level.

Note:

The profiling tolerance is + 0 °C, -X °C (based on machine variation capability) whatever is required to control

the profile process but at no time will it exceed - 5 °C. The producer assures process compatibility at the peak

reflow profile temperatures.

Note:

Package volume excludes external terminals (balls, bumps, lands, leads) and/or nonintegral heat sinks.

Note:

The maximum component temperature reached during reflow depends on package thickness and volume. The

use of convection reflow processes reduces the thermal gradients between packages. However, thermal

gradients due to differences in thermal mass of SMD packages may still exist.

STAC4932F1MR

Recommended heat profile and reflow soldering

DS9904 - Rev 2

page 8/16