MAX619
Regulated 5V Charge-Pump
DC-DC Converter
6 ________________________________________________________________________________________
Table 1. Capacitor Suppliers
* Note: (SM) denotes surface-mount component, (TH) denotes through-hole component.
__________Applications Information
Capacitor Selection
Charge-Pump Capacitors C1 and C2
The values of charge-pump capacitors C1 and C2 are
critical to ensure adequate output current and avoid
excessive peak currents. Use values in the range of
0.22µF to 1.0µF. Larger capacitors (up to 50µF) can
be used, but larger capacitors will increase output rip-
ple. Ceramic or tantalum capacitors are recommend-
ed.
Input and Output Capacitors, C3 and C4
The type of input bypass capacitor (C3) and output fil-
ter capacitor (C4) used is not critical, but it does affect
performance. Tantalums, ceramics, or aluminum elec-
trolytics are suggested. For smallest size, use Sprague
595D106X0010A2 surface-mount capacitors, which
measure 3.7mm x 1.8mm (0.146in x 0.072in). For low-
est ripple, use large, low effective-series-resistance
(ESR) ceramic or tantalum capacitors. For lowest cost,
use aluminum electrolytic or tantalum capacitors.
Figure 2 shows the component values for proper oper-
ation using minimal board space. The input bypass
capacitor (C3) and output filter capacitor (C4) should
both be at least 10µF when using aluminum electrolyt-
ics or Sprague’s miniature 595D series of tantalum chip
capacitors.
When using ceramic capacitors, the values of C3 and
C4 can be reduced to 2µF and 1µF, respectively. If the
input supply source impedance is very low, C3 may not
be necessary.
Many capacitors exhibit 40% to 50% variation over
temperature. Compensate for capacitor temperature
coefficient by selecting a larger nominal value to
ensure proper operation over temperature. Table 1 lists
capacitor suppliers.
MAX619
C4
10µF
IN
C1+
C1–
OUT
SHDN
C2+
C2–
GND
7
4
5
6
2
1
8
3
C3
10µF
2
CELLS
C1
0.22µF
C2
0.22µF
5V ±4%
@ 20mA
Figure 2. Two-Cell to 5V Application Circuit
10µF tantalum (SM)
595D106X0010A2
(603) 224-1430
(207) 324-7223
(603) 224-1961
(207) 327-4140
Sprague Electric
(smallest size)
0.1µF ceramic (TH)
RPE121Z5U104M50V
(814) 238-0490(814) 237-1431Murata Erie
1.0µF ceramic (TH)
RPI123Z5U105M50V
0.22µF ceramic (SM)
GRM42-6Z5U22M50
0.1µF ceramic (SM)
GRM42-6Z5U10M50
CAPACITOR TYPE*CAPACITORFAX NUMBERPHONE NUMBERSUPPLIER
(20 paginas)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comentarios a estos manuales