BZA420A NXP Semiconductors, BZA420A Datasheet - Page 7

• Manufacturer Part Number: BZA420A
• Description: Monolithic transient voltage suppressor diode in a six leadSOT457 (SC-74) package for 4-bit wide ESD transientsuppression at 20 V level
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Device placement and printed-circuit board layout
Circuit board layout is of extreme importance in the
suppression of transients. The clamping voltage of the
BZA420A is determined by the peak transient current and
the rate of rise of that current (di/dt). Since parasitic
inductances can further add to the clamping voltage
(V = L di/dt) the series conductor lengths on the
printed-circuit board should be kept to a minimum. This
includes the lead length of the suppression element.
In addition to minimizing conductor length the following
printed-circuit board layout guidelines are recommended:
1. Place the suppression element close to the input
2. Keep parallel signal paths to a minimum
3. Avoid running protection conductors in parallel with
4. Minimize all printed-circuit board loop areas including
5. Minimize the length of the transient return path to
6. Avoid using shared transient return paths to a common
1999 May 20
Quadruple ESD transient voltage
suppressor
terminals or connectors
unprotected conductors
power and ground loops
ground
ground point.
7
Product data sheet
BZA420A