APPLICATION NOTES

The MSK5824RH contains three internal 4.7μF tantalum

output capacitors, type CWR19HB475KCBB.The capacitor

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.

Low ESR output capacitors are required to maintain regu-

lation and stability. Four CWR29FB227 (AVX PN

TAZH227K010L) tantalum capacitors in parallel with ce-

ramic decoupling capacitors (0.1μF typical) provides suf-

ficient gain and phase margin for most applications. The

maximum ESR specification for the CWR29FB227 capaci-

tor is 180mΩ at 100kHz and is sufficient for many appli-

cations. MSK has found through full WCCA that screen-

ing for a maximum ESR of 57mΩ ensures EOL stability

criteria to be met for many applications with the most

stringent requirements. The typical ESR of the

TAZH227K010L from AVX is 49mΩ . Analysis of the fi-

nal design is recommended to ensure stability require-

ments are met.

INPUT POWER SUPPLY BYPASSING

3

FIGURE 1

Overcurrent protection is provided by the MSK5824RH

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 22mS 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 VIN off

then back on. At elevated temperatures or input voltages

the device may simply limit the output current without

activating the latch feature. A thermal limit condition will

trigger the latch with no time out delay.

OVERCURRENT LATCH

The MSK5824RH contains an internal 4.7μF tantalum in-

put 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 sys-

tem designer must ensure proper de-rating in accordance

with their system requirements. To maximize transient re-

sponse and minimize power supply transients it is recom-

mended that two 47μF tantalum capacitors are connected

between VIN and ground. A 0.1μF ceramic capacitor should

also be used for high frequency bypassing. See typical appli-

cation circuit.

CURRENT LIMIT AND SOA

The MSK5824RH current limit function is directly affected

by the input and output voltages. Figure 1 illustrates the rela-

is very important for the user to consult the SOA curve when

using input voltages which result 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 current limit is adjusted internally for an input voltage of

3.3V.

OUTPUT CAPACITOR SELECTION

VIN- These pins provide power to all internal circuitry includ-

ing bias, start-up, thermal limit and overcurrent latch. Input

voltage range is 2.9V to 6.5V but the MSK5824RH is opti-

mized for 3.3V input. See MSK5826RH 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 voltage applied to the SHUT-

DOWN pin can be greater than the input voltage. The output

voltage will turn on when the SHUTDOWN pin is pulled be-

low the threshold 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 condi-

tion can only be reset by cycling power off, then on.

VOUT - These are the output pins for the device.

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).

PIN FUNCTIONS

8548-58 Rev. H 6/14