Chip topography – Rainbow Electronics MAX861 User Manual
Page 9
MAX860/MAX861
50mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
_______________________________________________________________________________________
9
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
–
S
—
H
—
D
—
N
–
. MAX660, MAX665, and ICL7660 nor-
mal operation is with OSC floating (although OSC can
be overdriven). If OSC is floating, pin 7 (
–
S
—
H
—
D
—
N
–
) should
be jumpered to V
DD
to enable the MAX860/MAX861
permanently. Do not leave
–
S
—
H
—
D
—
N
–
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.
MAX860
MAX861
8
7
5
V
OUT
= (2V
IN
) -
(V
FD1
) - (V
FD2
)
C2
+V
IN
C1
2
3
4
V
OUT
= -V
IN
C4
D1
D1, D2 = 1N4148
C3
D2
Figure 3. Combined Doubler and Inverter
PART
NUMBER
OUTPUT
CURRENT
(mA)
OUTPUT
RESISTANCE
(
Ω
)
SWITCHING
FREQUENCY
(kHz)
MAX660
100
6.5
5/40
MAX665
100
6.5
5/40
MAX860
50
12
6/50/130
MAX861
50
12
13/100/250
ICL7660
10
55
5
Table 5. Product Selection Guide
TRANSISTOR COUNT: 101
SUBSTRATE CONNECTED TO V
DD
V
DD
SHDN
OUT
LV
FC
C1+
GND
C1-
0.084"
(2.13mm)
0.058"
(1.47mm)
___________________Chip Topography