AS1751/AS1752/AS1753
Data Sheet
- A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
Power Supply Sequencing
Proper power-supply sequencing is critical for proper switch operation. The power supplies should be started up in the
following sequence:
1. V+
2. NO
x,
NC
x,
COM
x
Note:
Do not exceed the absolute maximum ratings
Overvoltage Protection
ON-resistance increases slightly at lower supply voltages.
Figure 12. Overvoltage Protection using 2 External Blocking Diodes
AS1751/AS1752/AS1753
D1
V+
V+
COMx
V
GEN
NOx
GND
D2
Adding diode D2 to the circuit shown in
causes the logic threshold to be shifted relative to GND. Diodes D1
and D2 also protect against overvoltage conditions.
For example, in the circuit shown in
if the supply voltage goes below the absolute maximum rating, and if a
fault voltage up to the absolute maximum rating is applied to an analog signal pin, no damage will result.
Power Supply Bypass
Power supply connections to the devices must maintain a low impedance to ground. This can be done using a bypass
capacitor, which will also improve noise margin and prevent switching noise propagation from the V+ supply to other
components.
A 0.1µF bypass capacitor, connected from V+ to GND
is adequate for most applications.
Logic Inputs
Driving IN
x
Rail-to-Rail will help minimize power consumption.
Layout Considerations
High-speed switches require proper layout and design procedures for optimum performance.
!
!
!
Short, wide traces should be used to reduce stray inductance and capacitance.
Bypass capacitors should be as close to the device as possible.
Large ground planes should be used wherever possible.
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