SP6641BEK-L-5-0 Datasheet, PDF (10/13 Pages) Sipex Corporation – 500mA Alkaline DC/DC Boost Regulator in SOT-23

APPLICATION INFORMATION: continued
+0.9V to +3.3V Input
V_BATT
L1
+
C1
22µF
22µH
®
1
LX
U1 ^VBATT ⁵
2
SP6641
D1
GND
1
3
V_OUT
SHDN ^{4 2} J1
3
C2 ⁺
22µF
V_OUT
+3.3V
1 _VIN
® _VOUT 5
2 _{GND SP6201}
3 _ENABLE
4
RESET
Figure 15. SP6641A 3.3V Evaluation Board with SP6201 LDO Regulator
V_OUT
+3.0V
C3
1µF
SuperCap Application on the
SP6641 Output
When the battery input to SP6641A is removed,
the SP6641A output will end up in the charge
mode and will slowly discharge a Supercap
connected to the output. The typical Supercap
of 0.22F will go from fully charged at 3.3V to
less than 2V in 5 minutes. The following appli-
cation circuit in figure 16 is recommended to
disconnect the SP6641 output from the SuperCap
when the battery is removed. The small SOT23-
3pin MOS switches are an inexpensive addition
to the SP6641 circuit and work well to maintain
SuperCap voltage to retain Non-Volatile CMOS
Memory while a battery is changed.
TABLE 2. SP6641A Resistive Load Current in Startup - low cost inductors
SP6641A APPLICATION CIRCUIT WITH PANASONIC INDUCTOR SP6641A APPLICATION CIRCUIT WITH TDK INDUCTOR
L1 = ELJ-PB220KF 22µH, IDCmax = 300mA, DCR = 1.0Ω L1 = NLC453232T-220K 22µH, IDCmax = 370mA, DCR = 0.9Ω
Startup
V_OUT
I_OUT
Startup
Startup
V_OUT
I_OUT
Startup
Load
after
after
then
Load
after
after
then
V_IN
R_OUT (min) Startup
Startup
Load
V_IN
R_OUT (min) Startup Startup
Load
V
Ω
V
mA
mA (max)
V
Ω
V
mA
mA (max)
0.86 16000 3.31
0.2
37
0.86 16000 3.30
0.2
42
0.88 1500 3.31
2
39
0.88 1500 3.30
2
43
0.90
800
3.30
4
40
0.90
900
3.30
4
44
0.95
230
3.30
14
44
0.95
260
3.30
13
48
1.00
125
3.30
26
48
1.00
126
3.30
26
52
1.10
73
3.29
45
56
1.10
66
3.29
50
60
1.20
58
3.29
57
63
1.20
49
3.29
67
69
1.30
50
3.28
66
71
1.30
43
3.29
77
77
1.40
43
3.28
76
78
1.40
39
3.29
84
84
1.50
39
3.28
84
86
1.50
36
3.29
91
91
Rev. 5/26/05, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
10
© Copyright 2002 Sipex Corporation