Table 3. component selection guide, Table 4. component suppliers – Rainbow Electronics MAX1765 User Manual
Page 17
where I
LIM
is the peak inductor current limit, f
SW
is the
operating frequency (typically 1.2MHz), L is the induc-
tance of the chosen inductor, L
RESR
is the resistance of
the chosen inductor, R
NCH
and R
PCH
are the resis-
tances of the internal N-channel and P-channel,
respectively.
Table 5 lists the typical available output current when oper-
ating with one or more NiCd/NiMH cells or one Li+ cell.
Adding a Manual Power Reset
A momentary pushbutton switch can be used to turn
the MAX1765 on and off (Figure 11). ONA is pulled low
and ONB is pulled high to turn the device off. When the
momentary switch is pressed, ONB is pulled low and
I
I
I
I D
I
f
D
L
V
I
R
L
D
V
V
I
R
L
V
I
R
R
OUT MAX
LIM
RIPPLE
RIPPLE
SW
IN
LIM
NCH
ESR
OUT
IN
LIM
NCH
ESR
OUT
LIM
PCH
NCH
,
=
−
−
( )
=
Ч
Ч
−
Ч
+
(
)
[
]
=
−
+
Ч
+
(
)
+
−
(
)
2
1
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
______________________________________________________________________________________
17
Figure 9. Soft-Start, Maximum Current Limit
C
SS
R
SS
I
LIM
= 1.25A
t
SS
=
R
SS
C
SS
500k
Ω <
R
SS
<
1M
Ω
MAX1765
REF
ISET
0.22
µF
Figure 8. Soft-Start, Reduced Current Limit
C
SS
MAX1765
REF
ISET
0.22
µF
R
SS1
R
SS2
I
LIM
= 1.25A
t
SS
= (
R
SS1
||
R
SS2
)
C
SS
(
)
R
SS2
R
SS1
+
R
SS2
Table 3. Component Selection Guide
PRODUCTION
3.3
µH INDUCTORS
CAPACITORS
SCHOTTKY DIODES
Surface Mount
Coilcraft DS3316P
Coilcraft LPT3305
AVX TPS series
Kemet T510 series
Sanyo POSCAP series
Motorola MBR0520L
Nihon EP10QY03
Table 4. Component Suppliers
SUPPLIER
COUNTRY
PHONE
AVX
USA
843-448-9411
Coilcraft
USA
847-639-6400
Kemet
USA
810-287-2536
USA
408-629-4789
Motorola
Japan
81-45-474-7030
USA
847-956-0666
Sumida
Japan
81-3-3607-3302
Note: Please indicate that you are using the MAX1765 when
contacting these component suppliers.