LD6938_SER All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Objective data sheet Rev. 1 — 11 July 2013 10 of 15
NXP Semiconductors
LD6938 series
Dual low-dropout regulators, low noise, 300 mA
12. PCB assembly guidelines for Pb-free soldering
Table 11. Assembly recommendations
Parameter Value or specification
Solder screen thickness 100 m (0.004 inch)
Solder paste: Pb-free SnAg (3 % to 4 %); Cu (0.5 % to 0.9 %)
Solder to flux ratio 50 : 50
Solder reflow profile see Figure 6
The device can withstand at least three reflows at this profile.
Fig 6. Pb-free solder reflow profile
Table 12. Characteristics
Symbol Parameter Conditions Min Typ Max Unit
T
reflow(peak)
peak reflow temperature 230 - 260 C
t
1
time 1 soak time 60 - 180 s
t
2
time 2 time during T 250 C--30s
t
3
time 3 time during T 230 C10-50s
t
4
time 4 time during T > 217 C 30 - 150 s
t
5
time 5 - - 540 s
dT/dt rate of change of
temperature
cooling rate - - 6 C/s
preheat 2.5 - 4.0 C/s
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T
reflow(peak)
250
230
217
T
(°C)
cooling rate
preheat
t
1
t
5
t
4
t
3
t
2
t (s)
