ZXCL200 View Datasheet(PDF) - Zetex => Diodes
Part Name
Description
Manufacturer
ZXCL200 Datasheet PDF : 9 Pages
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APPLICATIONS INFORMATION
Enable Control
A TTL compatible input is provided to allow the
regulator to be shut down. A low voltage on the Enable
pin puts the device into shutdown mode. In this mode
the regulator circuit is switched off and the quiescent
current reduces to virtually zero (typically less than
10nA). A high voltage on the Enable pin ensures
normal operation.
The Enable pin can be connected to VIN or driven from
an independent source of up to 10V maximum. (e.g.
CMOS logic) for normal operation. There is no clamp
diode from the Enable pin to VIN, so the VIN pin may be
at any voltage within its operating range irrespective of
the voltage on the Enable pin.
Current Limit
The ZXCL200 device includes a current limit circuit
which restricts the maximum output current flow to
typically 200mA. Practically the range of over-current
should be considered as minimum 105mA to
maximum 750mA. The device’s robust design means
that an output short circuit to any voltage between
ground and VOUT can be tolerated for an indefinite
period.
Thermal Overload
Thermal overload protection is included on chip. When
the device junction temperature exceeds a minimum
125°C the device will shut down. The sense circuit will
re-activate the output as the device cools. It will then
cycle until the overload is removed. The thermal
overload protection will be activated when high load
currents or high input to output voltage differentials
cause excess dissipation in the device.
Start up delay
A small amount of hysteresis is provided on the Enable
pin to ensure clean switching. This feature can be used
to introduce a start up delay if required. Addition of a
simple RC network on the Enable pin provides this
function. The following diagram illustrates this circuit
connection. The equation provided enables calculation
of the delay period.
ZXCL200
R
C
Figure 1
Circuit Connection
Td
Figure 2
Start up delay (Td)
Td(NOM)
=
RCIn
VIN
VIN − 1.5
Calculation of start up delay as above
ISSUE 1 - SEPTEMBER 2001
7
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