Datasheet
MAX4506/MAX4507
Fault-Protected, High-Voltage
Signal-Line Protectors
_______________________________________________________________________________________ 7
8-Pin
DIP/SO
18-Pin
DIP/SO
NAME*
1, 2, 3 1, 2, 3 IN1, IN2, IN3
PIN
— 4–8 IN4, IN5, IN6, IN7, IN8
4 9 V-
— — N.C.
8 18 V+
5, 6, 7 15, 16, 17 OUT3, OUT2, OUT1
— 10–14 OUT8, OUT7, OUT6, OUT5, OUT4
Pin Description
FUNCTION
Signal Inputs 1, 2, 3
Signal Inputs 4, 5, 6, 7, 8
Negative Supply Voltage Input
No Connection. Not internally connected.
Positive Supply-Voltage Input
Signal Outputs 3, 2, 1
Signal Outputs 8, 7, 6, 5, 4
20-Pin
SSOP
1, 2, 4
5–9
10
3, 18
20
16, 17, 19
11–15
MAX4506 MAX4507
* Connect all unused inputs to a hard voltage within the supply range (e.g., V+, V-, or GND).
Detailed Description
The MAX4506/MAX4507 protect other ICs from over-
voltage by clamping its output voltage to the supply
rails. If the power supplies to the device are off, the
device clamps the output to 0V. The MAX4506/
MAX4507 provide protection for input signals up to
±36V with the power supplies on and ±40V with the
power supplies off.
The MAX4506/MAX4507 protect other integrated cir-
cuits connected to its output from latching up. Latchup
is caused by parasitic SCR(s) within the IC turning on,
and can occur when the supply voltage applied to the
IC exceeds the specified operating range. Latchup can
also occur when signal voltage is applied before the
power-supply voltage. When in a latchup state, the cir-
cuit draws excessive current and may continue to draw
excessive current even after the overvoltage condition
is removed. A continuous latchup condition may dam-
age the device permanently. Such “faults” are com-
monly encountered in modular control systems where
power supplies to interconnected modules may be
interrupted and reestablished at random. Faults can
happen during production testing, maintenance, start-
up, or a power failure.
Figure 1 shows the normal complementary pair (N1 and
P1) found in many common analog switches. In addi-
tion to these transistors, the MAX4506/MAX4507 also
contain comparators and sensing and clamping circuitry
to control the state of N1 and P1. During normal opera-
tion, N1 and P1 remain on with a typical 65Ω on-resis-
tance between IN and OUT.
The on-board comparators and sensing circuitry moni-
tor the input voltage for possible overvoltage faults.
-15V
-15V
+15V
P-CHANNEL
DRIVER
N-CHANNEL
DRIVER
+15V
N3
P3
IN
N1
CLAMP
OUT
CLAMP
+V(+15V)
-V(-15V)
N2
P2
P1
COMPARATOR
COMPARATOR
SENSE
SWITCH
SENSE
SWITCH
Figure 1. Simplified Internal Structure