Application Information (continues)
Error Flag
Large output capacitors are not required to obtain this
performance. standard 10uF output capacitor,
TS39101 versions feature an Error Flag, which looks
at the output voltage and signals an error condition
when this voltage drops 5% below its expected value.
The error flag is an open-collector output that pulls low
under fault conditions. It may sink 10mA. Low output
voltage signifies a number of possible problems,
including an over-current fault (the device is in current
limit) or low input voltage. The flag output is
inoperative during over temperature shutdown
conditions. A pull-up resistor from error flag to either
Vin or Vout is required for proper operation. For
information regarding the minimum and maximum
values of pull-up resistance, refer the graph as follow:
A
preferably tantalum, is all that is required. Larger values
help to improve performance even further.
By virtue of its low dropout voltage, this device does not
saturate into dropout as readily as similar NPN base
designs. When converting from 3.3V to 2.5V or 2.5V to
1.8V, the NPN based regulators are already operating
in dropout, with typical dropout requirements of 1.2V or
greater,. To convert down to 2.5V or 1.8V without
operating in dropout, NPN based regulators require an
input voltage of 3.7V at the very least.
The TS39100 regulator will provide excellent
performance with an input as low as 3.0V or 2.5V
respectively. This gives the PNP based regulators a
distinct advantage over older, NPN based linear
regulators.
Power SOP-8 Thermal Characteristics
TS39101/2 series’ performance is its power SOP-8
package featuring half the thermal resistance of a
standard SOP-8 package. Lower thermal resistance
means more output current or higher input voltage for a
given package size.
Lower thermal resistance is achieved by connect the
four ground pins with the die attached pad to create a
single piece electrical and thermal conductor. This
concept have been used by MOSFET production for
years, proving very reliable and cost effective for the
user. As under:
Enable Input
TS39101/2/3 versions feature an active-high enable
(EN) input that allows ON/OFF control of the regulator.
Current drain reduces to “zero” when the device is
shutdown, with only micro-amperes of leakage current.
The EN input has TTL/CMOS compatible thresholds
for simple interfacing with logic interfacing. EN may be
directly tied to Vin and pulled up to the maximum
supply voltage.
Transient Response and 3.3V to 2.5V
or 2.5V to 1.8V Conversion
TS39101/2/3 has excellent transient response to
variations in input voltage and load current. The device
have been designed to respond quickly to load current
variations and input voltage variations.
TS39100/1/2/3
7-10
2004/06 rev. E
TSC [ TAIWAN SEMICONDUCTOR COMPANY, LTD ]
