MAX4507EAP+ Maxim Integrated Products, MAX4507EAP+ Datasheet - Page 8

• Manufacturer Part Number: MAX4507EAP+
• Description: IC SIGNAL LINE PROTECTOR 20-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Overvoltage protectionr

Specifications of MAX4507EAP+

• Applications: Control systems
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Two clamp circuits limit the output voltage to within the
supply voltages. When the power supplies are off, any
input voltage applied at IN turns off both N1 and P1,
and OUT is clamped to 0V.
When power is applied, each protector acts as a resis-
tor in series with the signal path. Any voltage source on
the “input” side of the switch will be conducted through
the protector to the output (Figure 2).
When the output load is resistive, it draws current
through the protector. The internal resistance is typically
less than 100Ω. High-impedance loads are relatively
unaffected by the presence of the MAX4506/MAX4507.
The protector’s path resistance is a function of the supply
voltage and the signal voltage (see Typical Operating
Characteristics).
When power is off (i.e., V+ = V- = 0), the protector is a
virtual open circuit. With up to ±40V applied to the input
pin, the output pin will be 0V.
A fault condition exists when the voltage on the IN_
exceeds either supply rail. This definition is valid when
power is on or off, as well as during all states while
power ramps up or down.
The MAX4506/MAX4507 have low supply currents
(<250µA), which allows the supply pins to be driven by
other active circuitry instead of connected directly to
the power sources. In this configuration, the parts can
be used as driven fault-protected switches with V+ or
V- used as the control pins. For example, with the V-
pin grounded, the output of a CMOS gate can drive the
V+ pin to turn the device on and off. This can effectively
connect and disconnect three (MAX4506) or eight
(MAX4507) separate signal lines at once. Ensure that
the driving source(s) does not drive the V+ pin more
negative than the V- pin.
Figure 3 shows a simple turn-on delay that takes
advantage of the MAX4506’s low power consumption.
The two RC networks cause gradual application of
power to the MAX4506, which in turn applies the input
signals smoothly after the amplifier has stabilized. The
Fault-Protected, High-Voltage
Signal-Line Protectors
8
_______________________________________________________________________________________
Supplying Power Through External ICs
Applications Information
Fault Protection, Power Off
Fault Protection, Power On
Normal Operation
two diodes discharge the two capacitors rapidly when
the power turns off. Note that the IC used to supply
power to the MAX4506/MAX4507 must be able to sup-
ply enough current to maintain the load voltage at the
supply rail in a fault condition.
Figure 2. Application Circuit
Figure 3. Turn-On Delay
1
2
3
4
V
IN1
IN2
IN3
V-
V-
IN
MAX4506
4
1
IN1
V-
OUT1
OUT2
OUT3
MAX4506
V+
8
7
6
5
10µF
10µF
OUT1
V+
8
7
100kΩ
100kΩ
V+
R
OP AMP
OUT
+15V
-15V