MAX660MJA Maxim Integrated Products, MAX660MJA Datasheet - Page 6

• Manufacturer Part Number: MAX660MJA
• Description: Charge Pumps
• Manufacturer: Maxim Integrated Products

Specifications of MAX660MJA

• Function: Inverting, Step Up
• Output Voltage: - 1.5 V to - 5.5 V, 3 V to 11 V
• Output Current: 100 mA
• Maximum Operating Temperature: + 125 C
• Package / Case: CDIP-8
• Minimum Operating Temperature: - 55 C
• Mounting Style: Through Hole
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

CMOS Monolithic Voltage Converter
The MAX660 capacitive charge-pump circuit either
inverts or doubles the input voltage (see Typical
Operating Circuits). For highest performance, low
effective series resistance (ESR) capacitors should be
used. See Capacitor Selection section for more details.
When using the inverting mode with a supply voltage
less than 3V, LV must be connected to GND. This
bypasses the internal regulator circuitry and provides
best performance in low-voltage applications. When
using the inverter mode with a supply voltage above
3V, LV may be connected to GND or left open. The part
is typically operated with LV grounded, but since LV
may be left open, the substitution of the MAX660 for the
ICL7660 is simplified. LV must be grounded when over-
driving OSC (see Changing Oscillator Frequency sec-
tion). Connect LV to OUT (for any supply voltage) when
using the doubling mode.
The most common application of the MAX660 is as a
charge-pump voltage inverter. The operating circuit
uses only two external capacitors, C1 and C2 (see
Typical Operating Circuits).
Even though its output is not actively regulated, the
MAX660 is very insensitive to load current changes. A
typical output source resistance of 6.5Ω means that
with an input of +5V the output voltage is -5V under
light load, and decreases only to -4.35V with a load of
100mA. Output source resistance vs. temperature and
supply voltage are shown in the Typical Operating
Characteristics graphs.
Output ripple voltage is calculated by noting the output
current supplied is solely from capacitor C2 during
Table 1. Single-Output Charge Pumps
6
Package
Op. Current
(typ, mA)
Output Ω
(typ)
Pump Rate
(kHz)
Input (V)
__________Applications Information
______________Detailed Description
_______________________________________________________________________________________
1.25 to 5.5
MAX828
SOT 23-5
0.06
20
12
Negative Voltage Converter
1.25 to 5.5
MAX829
SOT 23-5
0.15
20
35
1.4 at 130kHz
0.6 at 50kHz,
0.2 at 6kHz,
MAX860
6, 50, 130
1.5 to 5.5
SO-8,
µMAX
12
1.1 at 100kHz,
2.5 at 250kHz
0.3 at 13kHz,
13, 100, 150
MAX861
1.5 to 5.5
µMAX
SO-8,
12
one-half of the charge-pump cycle. This introduces a
peak-to-peak ripple of:
For a nominal f
10kHz oscillator frequency) and C2 = 150µF with an
ESR of 0.2Ω, ripple is approximately 90mV with a
100mA load current. If C2 is raised to 390µF, the ripple
drops to 45mV.
The MAX660 operates in the voltage-doubling mode as
shown in the Typical Operating Circuit. The no-load
output is 2 x V
Please refer to Table 1, which shows Maxim’s charge-
pump offerings.
Four modes control the MAX660’s clock frequency, as
listed below:
When FC and OSC are unconnected (open), the oscil-
lator runs at 10kHz typically. When FC is connected to
V+, the charge and discharge current at OSC changes
from 1.0µA to 8.0µA, thus increasing the oscillator
FC
Open
FC = V+
Open or
Open
FC = V+
0.12 at 5kHz,
1 at 40kHz
MAX660
1.5 to 5.5
Other Switched-Capacitor Converters
SO-8
5, 40
6.5
V
RIPPLE
IN
OSC
Open
Open
External
Capacitor
External
Clock
Changing Oscillator Frequency
.
PUMP
=
MAX1044
1.5 to 10
µMAX
SO-8,
0.03
2(f
6.5
5
of 5kHz (one-half the nominal
Positive Voltage Doubler
PUMP
I
OUT
Oscillator Frequency
10kHz
80kHz
See Typical Operating
Characteristics
External Clock Frequency
) (C2)
ICL7662
1.5 to 10
SO-8
0.25
125
10
+ I
OUT
(ESR
ICL7660
1.5 to 10
µMAX
SO-8,
0.08
55
10
C2
)