MSK5824RH M. S Kennedy, MSK5824RH Datasheet - Page 3

• Manufacturer Part Number: MSK5824RH
• Description: Rad Hard Ultra Low Dropout Positive Adjustable Linear Regulator
• Manufacturer: M. S Kennedy

PIN FUNCTIONS
V
including bias, start-up, thermal limit and overcurrent latch.
Input voltage range is 2.9V to 6.5V but the MSK 5824RH
is optimized for 3.3V input. See MSK 5826RH for 5V
input version.
GND - Internally connected to ground, these pins should
be connected externally by the user to the circuit ground.
SHUTDOWN - There are two functions to the SHUTDOWN
pin. It may be used to disable the output voltage or to
reset a current latch condition. To activate the shutdown/
reset functions the user must apply a voltage greater than
1.6V to the SHUTDOWN pin. The output voltage will turn
on when the SHUTDOWN pin is pulled below the thresh-
old voltage. If the SHUTDOWN pin is not used, it should
be connected to ground. It should be noted that with the
shutdown pin tied to ground, a current latch condition
can only be reset by cycling power off, then on.
V
ADJUST - This pin is used to set the output voltage. Con-
nect a resistor between the adjust pin (4) and the output
pins (5 and 6) to fix the output voltage at the desired
value. Use the following equations to determine the nomi-
nal value of the adjust resistor (RADJ).
series through the use of a timed latch off circuit. The
internal latch timeout is triggered by an overcurrent con-
dition. To allow for start up surge currents, the timeout is
approximately TBDmS at 25°C. If the overcurrent condi-
tion remains at the end of the timeout cycle, the regulator
will latch off until the latch is reset. To reset the latch,
toggle the shutdown pin high then low or cycle V
then back on. A thermal limit condition will trigger the
latch with no time out delay.
input capacitor, type CWR19HB475CBB. The capacitor
is rated for 15V maximum applied voltage and has been
surge tested in accordance with condition B of MIL-PRF-
55365. The system designer must ensure proper de-rat-
ing in accordance with their system requirements. To maxi-
mize transient response and minimize power supply tran-
sients it is recommended that a 100µF tantalum capaci-
tor is connected between V
ramic capacitor should also be used for high frequency
bypassing.
OVERCURRENT LATCH
INPUT POWER SUPPLY BYPASSING
Overcurrent protection is provided by the MSK 5824RH
IN
OUT
The MSK 5824RH contains an internal 4.7µF tantalum
APPLICATION NOTES
- These pins provide power to all internal circuitry
- These are the output pins for the device.
V
R
ADJ
OUT
=(V
=V
REF
OUT
x (1 + R
/V
REF
- 1) x 1K
IN
ADJ
and ground. A 0.1µF ce-
/1K )
IN
off
3
OUTPUT CAPACITOR SELECTION
CURRENT LIMIT AND SOA
fected by the input and output voltages. Figure 1 illus-
trates the relationship between V
output voltages. It is very important for the user to con-
sult the SOA curve when using input voltages which re-
sult in current limit conditions beyond 3.5 Amps. When
using input voltages which result in current limit above
3.5 Amps, the user must maintain output current within
the SOA curve to avoid damage to the device. The cur-
rent limit is adjusted internally for an input voltage of 3.3V.
lum output capacitors, type CWR19HB475KCBB.The ca-
pacitor are rated for 15V maximum applied voltage and
have been surge tested in accordance with condition B of
MIL-PRF-55365. The system designer must ensure proper
de-rating in accordance with their system requiremenets.
Output capacitors are required to maintain regulation and
stability. A 220µF surface mount tantalum capacitor from
the output to ground should suffice under most condi-
tions. Ceramic output capacitors (0.1µF typical) should
be placed directly across the load power connections as
close to the load as possible. If the user finds that tighter
voltage regulation is needed during output transients, more
capacitance may be added. If more capacitance is added
to the output, the bandwidth may suffer.
The MSK 5824RH contains three internal 4.7µF tanta-
The MSK 5824RH current limit function is directly af-
FIGURE 1
IN
and I
CL
Rev. A 1/09
for various