MF-USHT Datasheet, PDF (3/4 Pages) –

MF-USHT Series - PTC Resettable Fuses
Solder Reflow Recommendations
TP
TL
TS MAX.
TS MIN.
25
RAMP-UP
ts
PREHEAT
t 25 *C TO PEAK
Time
tp
tL
CRITICAL ZONE
TL TO TP
RAMP-DOWN
8 MINS.
Notes:
• MF-USHT models cannot be wave soldered or hand soldered. Please
contact Bourns for soldering recommendations.
• All temperatures refer to topside of the package, measured on the
package body surface.
• If reflow temperatures exceed the recommended profile, devices may
not meet the published specifications.
• Compatible with Pb and Pb-free solder reflow profiles.
• Excess solder may cause a short circuit, especially during hand
soldering. Please refer to the Multifuse^® Polymer PTC Soldering
Recommendation guidelines.
• Designed for single solder reflow operations.
Profile Feature
Average Ramp-Up Rate (TS_max to T_p)
PREHEAT:
Temperature Min. (TS_min)
Temperature Max. (TS_max)
Time_Pro(t_cs_emssin to ts_max)
TIME_DM_esA_crI_iN_ptT_ioA_nINED ABOVE:
Materials
Temperature
1. App^Tly^es^mol^pde^er^rp^aa^ts^ute^reto^(TL) • Sn 96.5 / Ag 3.0 / Cu 0.5
test^Tbⁱo^mar^ed (⁽8^tL-⁾10 mil thick) Alloy water soluble or no
Room temperature
Peak / Classification Tem^cp_(lsee_eaerⁿa_nst_oou_tledre^e1r)(^pT^as_P^te)
Time within 5 °C of Actu^•a^s(l_GinP_1g0e^le)a_(sUk^idLeT^dae_pem_pprop_oxve^yer_dga_)latu^ssre (t_p)
Ramp-Down Rate
• PC board approx. 4x4x.06 in.
23.._TPR_ila_mamc_eeptu_wesp_it_thun_inits₂o₅nto_°Cbo_ta_ord_PeC6aokunnv_Tite_esc/_{mtbioopnareodrvaenture}
(see note 2)
4. Preheat (TS)
150 °C to 190 °C
5. Time above liquidus (T_L)
6. Peak temperature (TP)
220 °C
7. Ramp down
8. Cleaning water clean profile High pressure deionized
water 65 PSI max.
Room temperature
(see note 2)
72 °F to 160 °F
(22 °C to 71 °C)
Temperature of Lead/Pad Junction
(Derived using 6-zone Convection Oven)
3 °C / second max.
Pb-Free Assembly
150 °C
200 °C
60~180
Time
s_Ie_nsc_po_en_ctd_ss_older
joint
to
determine
if
solder
joint
is
Interval
acceptable (i.e. exhibits wetting of joint’s surface).
217 °C
60~150
Use the following criteria (ref. acceptability
s^be^oc^ao^rdn^ad^ss^{semblies, IPC-A-610):}
of
printed
A) Acceptable (see Figure 1)
260 °C
(1) The solder connection wetting angle (solder to
20~40 seconds^{cdoomespnoontenext} _{caenedds9o0ld°e.r} ^{to PCB termination)}
6 °C / secon₍d₂₎m_Soa_ldx_e._{r balls that do not violate minimum}
2.5 °C ± 0.⁸5 °^m/sⁱeⁿc^u. ^{tes max.e(sleocldtreicreadl )clteoaraamnceetsalasnudrfaarceea. ttached}
90 ± 30 sec.
B) Unacceptable (see Figure 2)
60-90 sec.
250 °C +0 °/-5 °
10-20 sec. within
(1) Solder connection wetting angle exceeding
90 °.
(2) Incomplete reflow of solder paste.
5 °C of peak
(3) Dewetting.
3 °C ± 0.5 °C/sec. If unacceptable, determine cause and correct prior to
next run.
As required
NOTES:
1. Water soluble solder paste only above 100K.
2. Refer to ref. temperature profile. Temperature at
lead/pad junction with “K” type thermocouple.
3. Units that are board mounted for environmental
testing must see a peak temperature in the reflow
zone, as specified. This is to ensure that all test
units will see “worst case conditions”.
4. Ramp down rate to be measured from 245 °C to
150 °C.
5. Process Description 8 does not apply to open
frame trimmers.
MF-USHT SERIES, REV. A 06/17
“freeXpansion Design” is a trademark of Bourns, Inc.
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.