50mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
Table 5. Product Selection Guide
+V
IN
8
2
C1
3
4
7
D1, D2 = 1N4148
D1
5
C2
D2
C3
C4
V
OUT
= (2V
IN
) -
(V
FD1
) - (V
FD2
)
V
OUT
= -V
IN
MAX860/MAX861
PART
NUMBER
MAX660
MAX665
MAX860
MAX861
ICL7660
OUTPUT
CURRENT
(mA)
100
100
50
50
10
OUTPUT
SWITCHING
RESISTANCE FREQUENCY
(Ω)
(kHz)
6.5
6.5
12
12
55
5/40
5/40
6/50/130
13/100/250
5
MAX860
MAX861
Figure 3. Combined Doubler and Inverter
Compatibility with
MAX660/MAX665/ICL7660
The MAX860/MAX861 can be used in sockets
designed for the MAX660, MAX665, and ICL7660 with
a minimum of one wiring change. This section gives
advice on installing a MAX860/MAX861 into a socket
designed for one of the earlier devices.
The MAX660, MAX665, and ICL7660 have an OSC pin
–— –
— —
instead of SHDN. MAX660, MAX665, and ICL7660 nor-
mal operation is with OSC floating (although –
– — OSC can
— —
be overdriven). If OSC is floating, pin 7 (SHDN ) should
be jumpered to V
DD
to enable the MAX860/MAX861
–— –
— —
permanently. Do not leave SHDN on the MAX860/
MAX861 floating.
The MAX860/MAX861 operate with FC either floating or
connected to V
DD
, OUT, or GND; each connection
defines the oscillator frequency. Thus, any of the nor-
mal MAX660, MAX665, or ICL7660 connections to pin 1
will work with the MAX860/MAX861, without modifica-
tions. Changes to the FC connection are only required
if you want to adjust the operating frequency.
___________________Chip Topography
FC
V
DD
C1+
GND
0.084"
(2.13mm)
SHDN
C1-
LV
OUT
0.058"
(1.47mm)
TRANSISTOR COUNT: 101
SUBSTRATE CONNECTED TO V
DD
_______________________________________________________________________________________
9
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
