MAX860CSA+ Maxim Integrated Products, MAX860CSA+ Datasheet - Page 7

• Manufacturer Part Number: MAX860CSA+
• Description: IC VOLT CONV SW-CAP 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Switched Capacitor (Charge Pump), Doubler, Invertingr

Specifications of MAX860CSA+

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: -1.5 ~ -5.5 V, 3 ~ 11 V
• Current - Output: 50mA
• Frequency - Switching: 6kHz, 50kHz, 130kHz
• Voltage - Input: 1.5 ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Power - Output: 471mW
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX860/MAX861 are tested using 10µF capacitors
for both C1 and C2, although smaller or larger values
can be used (Table 3). Smaller C1 values increase the
output resistance; larger values reduce the output
resistance. Above a certain point, increasing the
capacitance of C1 has a negligible effect (because the
output resistance becomes dominated by the internal
switch resistance and the capacitor ESR). Low-ESR
capacitors provide the lowest output resistance and
ripple voltage. The output resistance of the entire circuit
(inverter or doubler) is approximately:
where R
MAX861’s internal switches) is approximately 8
is the switching frequency. R
using capacitors with 0.2
ues suggested in Table 3. When C1 and C2 are so
large (or the switching frequency is so high) that the
internal switch resistance dominates the output resis-
tance, estimate the output resistance as follows:
Table 2. Switching-Frequency Trade-Offs
Table 4. Low-ESR Capacitor Manufacturers
__________Applications Information
Output Ripple
C1, C2 Values
Supply Current
MANUFACTURER–Series
AVX TPS Series
AVX TAG Series
Matsuo 267 Series
Sprague 595 Series
Sanyo MV-GX Series
Sanyo CV-GX Series
Nichicon PL Series
United Chemicon (Marcon)
TDK
ATTRIBUTE
R
OUT
O
= R
R
(the effective resistance of the MAX860/
OUT
O
+ 4 x ESR
= R
_______________________________________________________________________________________
O
Switched-Capacitor Voltage Converters
FREQUENCY
+ 4 x ESR
LOWER
Smaller
Larger
Larger
C1
ESR and f
+ ESR
OUT
[phone]
[phone]
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Capacitor Selection
C1
is typically 12
C2
+ ESR
S
+ 1 / (f
, C1, and C2 val-
PHONE
FREQUENCY
C2
HIGHER
Smaller
Smaller
Larger
S
50mA, Frequency-Selectable,
x C1)
and f
when
S
[phone]
[phone]
[phone]
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[phone]
[phone]
[phone]
[phone]
A typical design procedure is as follows:
1) Choose C1 and C2 to be the same, for convenience.
2) Select f
3) Choose a capacitor based on Table 3, although
*In addition to Table 3, four graphs in the Typical
Operating Characteristics section show typical output
current for C1 and C2 capacitances ranging from
0.33µF to 22µF. Output current is plotted for inputs of
4.5V (5V - 10%) and 3.0V (3.3V - 10%), and also for
10% and 20% output droop from the ideal -V
Table 3. Suggested Capacitor Values*
NOMINAL FREQUENCY (kHz)
a) If you want to avoid a specific noise frequency,
b) If you want to minimize capacitor cost and size,
c) If you want to minimize current consumption,
higher or lower values can be used to optimize per-
formance. Table 4 lists manufacturers who provide
low-ESR capacitors.
choose f
choose a high f
choose a low f
FAX
S
:
S
100
130
250
13
50
6
appropriately.
S
S
.
.
Low-ESR tantalum, SMT
Low-cost tantalum, SMT
Low-cost tantalum, SMT
Low-ESR tantalum, SMT
Aluminum electrolytic, through hole
Aluminum electrolytic, SMT
Aluminum electrolytic, through hole
Ceramic SMT
Ceramic SMT
COMMENTS
C1, C2 (µF)
4.7
4.7
2.2
68
47
10
IN
value.
7