MIL-PRF-38534 CERTIFIED
M.S.KENNEDY CORP.
FEATURES:
RAD HARD ULTRA LOW
DROPOUT ADJUSTABLE
POSITIVE LINEAR REGULATOR
5821RH
(315) 701-6751
4707 Dey Road Liverpool, N.Y. 13088
Manufactured using
Space Qualified RH1573 Die
New "Harder" Version of MSK 5921RH
Total Dose Tested to 450K RAD (Method 1019.7 Condition A)
Ultra Low Dropout for Reduced Power Consumption
External Shutdown
Latching Overload Protection
Adjustable Output Using Two External Resistors
Output Current Limit
Available in 4 Lead Form Options: Straight, Up, Down and Gull Wing
Available to DSCC SMD 5962F09216
ELDRS Tested to 100 Krads(Si) (Method 1019.7 Condition D)
Neutron Tested to 1.0x10¹² n/cm² (Method 1017.2)
DESCRIPTION:
The MSK 5821RH is a radiation hardened adjustable linear regulator typically capable of delivering 5.0 amps of
output current. The typical dropout is only 0.22 volts with a 2.5A load. An external shutdown function is ideal for
power supply sequencing. This device also has latching overload protection that requires no external current sense
resistor. The MSK 5821RH is radiation hardened and specifically designed for space/satellite applications. The device
is packaged in a hermetically sealed space efficient 5 pin SIP that is electrically isolated from the internal circuitry
allowing for direct heat sinking.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
TYPICAL APPLICATIONS
Satellite System Power Supplies
Switching Power Supply Post Regulators
Constant Voltage/Current Regulators
Microprocessor Power Supplies
PIN-OUT INFORMATION
1
2
3
4
5
1
VIN
GND
VOUT
SHUTDOWN
ADJUST
Rev. G
1/11
ABSOLUTE MAXIMUM RATINGS
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8
ELECTRICAL SPECIFICATIONS
Parameter
Input Voltage Range
2
Test Conditions
1 11
10mA
≤
I
OUT
≤
1.0A
I
OUT
=1A R1=187Ω
Post 100K
RAD
(Si)
Post 300K
RAD
(Si)
Feedback Pin Current
2
Quiescent Current
V
FB
=1.265V 10mA
≤
I
OUT
≤
3.0A
VIN=6.5V
Not Including I
OUT
Line Regulation
9
I
OUT
=50mA
VOUT+0.4V
≤
VIN
≤
VOUT +1.3V
Load Regulation
9
50mA
≤
I
OUT
≤
3.0A
Delta FB=1% I
OUT
=2.5A
Group A
Subgroup
1
2,3
Feedback Voltage
1
2,3
1
1
1,2,3
1
2,3
1
2,3
1
2,3
Dropout Voltage
10
Minimum Output Current
2
1
2,3
2.9V
≤
VIN
≤
6.5V
R1=187Ω
Output Voltage Range
2
Output Current Limit
7
MSK5821K/H
Min.
2.9
2.9
1.225
1.225
1.225
1.225
0
-
-
-
-
-
-
-
-
-
-
1.5
3.0
3.0
1.0
1.0
65
65
30
10
-
-
Typ.
-
-
1.265
-
-
-
-
14
14
Max.
6.5
6.5
Min.
2.9
-
MSK5821
Typ.
-
-
1.265
-
-
-
-
14
-
0.01
-
0.06
-
0.22
-
8
-
-
4.0
-
1.3
-
-
-
-
18
-
2.5
Max.
6.5
-
1.328
-
1.328
1.328
5.0
20
-
1.305 1.202
1.305
-
1.305 1.202
1.310 1.202
5.0
20
20
0
-
-
-
-
-
-
-
-
-
-
1.5
3.0
-
1.0
-
65
-
30
10
-
-
±0.01 ±0.50
-
±2.5
±0.06 ±0.80
-
0.22
0.26
8
9
-
4.0
4.0
1.3
1.3
-
-
-
18
-
2.5
±2.5
0.40
0.40
10
10
6.0
5.0
5.0
1.6
1.6
-
-
-
-
50
2.9
±0.60 %V
OUT
-
%V
OUT
±1.0 %V
OUT
-
0.45
-
10
-
6.0
5.0
-
1.6
-
-
-
-
-
50
2.9
%V
OUT
V
V
mA
mA
V
A
A
V
V
dB
dB
degrees
dB
μV
RMS
°C/W
1
2,3
-
1
2,3
VIN=6.5V
VIN=3.5V VOUT=2.5V
Shutdown Threshold
VOUT
≤
0.2V (OFF)
VOUT=Nominal (ON)
f=120Hz
I
OUT
=50mA
1
2,3
4
5,6
4
4
Ripple Rejection
2
Phase Margin
2
Gain Margin
2
Equivalent Noise Voltage
2
Thermal Resistance
2
Referred to Feedback Pin
Junction to Case @ 125°C Output Device
4
-
NOTES:
1
2
3
4
5
6
7
8
9
10
11
12
Unless otherwise specified, VIN=5.0V, R1=1.62K, V
SHUTDOWN
=0V and I
OUT
=10mA. See Figure 2, typical application circuits.
Guaranteed by design but not tested. Typical parameters are representative of actual device performance but are for reference only.
Industrial grade devices shall be tested to subgroups 1 and 4 unless otherwise requested.
Military grade devices ("H" suffix) shall be 100% tested to subgroups 1,2,3 and 4.
Subgroup 5 and 6 testing available upon request.
Subgroup 1,4 T
C
=+25°C
Subgroup 2,5 T
C
=+125°C
Subgroup 3,6 T
A
=-55°C
Output current limit is dependent upon the values of VIN and VOUT. See Figure 1 and typical performance curves.
Continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle.
V
IN
shall be as specified or VIN Min, whichever is greater.
Not applicable when VOUT<VIN Min - dropout voltage maximum.
Pre and post irradiation limits, up to 300Krad TID, are identical unless otherwise specified.
Reference DSCC SMD 5962F09216 for electrical specification for devices purchased as such.
2
Rev. G
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P
D
T
C
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+V
IN
I
OUT
T
C
Supply Voltage
+10V
7
Output Current
5A
Case Operating Temperature Range
MSK5821K/H RH
-55°C to +125°C
MSK5821RH
-40°C to +85°C
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T
ST
T
LD
Storage Temperature Range -65°C to +150°C
300°C
Lead Temperature Range
(10 Seconds)
See SOA Curve
Power Dissipation
150°C
Junction Temperature
Units
V
V
V
V
V
V
μA
mA
mA
1/11
APPLICATION NOTES
PIN FUNCTIONS
VIN -
This pin provides power to all internal circuitry in-
cluding bias, start-up, thermal limit and overcurrent latch.
Input voltage range is 2.9V to 6.5V.
GND -
Internally connected to ground, this pin 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.
VOUT -
This is the output pin for the device.
ADJUST -
The ADJUST pin is the inverting input of the
internal error amplifier. The non-inverting input is con-
nected to an internal 1.265V reference. This error ampli-
fier controls the drive to the output transistor to force the
ADJUST pin to 1.265V. An external resistor divider is
connected to the output, ADJUST pin and ground to set
the output voltage.
OUTPUT CAPACITOR SELECTION
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 final
design is recommended to ensure stability requirements
are met.
OVERCURRENT LATCH
Overcurrent protection is provided by the MSK5821RH
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 5.5mS 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. Reset the latch by
pulling the shutdown pin high or cycling VIN off then back
on. A thermal limit condition will trigger the latch with no
time out delay.
FIGURE 1
CURRENT LIMIT AND SOA
The MSK 5821RH current limit function is directly af-
fected by the input and output voltages. Figure 1 illus-
trates the relationship between VIN and ICL for various
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 4.5 Amps. When
using input voltages which result in current limit above
4.5 Amps, the user must maintain output current within
the SOA curve to avoid damage to the device. Note that 5
Amp maximum is due to current carrying capability of the
internal wirebonds.
INPUT POWER SUPPLY BYPASSING
To maximize transient response and minimize power
supply transients it is recommended that two 47μF tanta-
lum capacitors are connected between VIN and ground.
A 0.1μF ceramic capacitor should also be used for high
frequency bypassing. See typical application circuit.
3
Rev. G
1/11
APPLICATION NOTES CONT.
THERMAL LIMITING
The MSK 5821RH control circuitry has a thermal shut-
down temperature of approximately 150°C. This ther-
mal shutdown can be used as a protection feature, but
for continuous operation, the junction temperature of the
pass transistor must be maintained below 150°C. Proper
heat sink selection is essential to maintain these condi-
tions. Exceeding the thermal limit activates the latch fea-
ture of the MSK 5821RH. Toggle the shutdown pin high
then low or cycle power to reset the latch. See SHUT-
DOWN pin description and overcurrent latch description
for more information.
TYPICAL APPLICATIONS CIRCUIT
HEAT SINK SELECTION
To select a heat sink for the MSK 5821RH, the follow-
ing formula for convective heat flow may be used.
FIGURE 2
Governing Equation:
T
J
=
P
D
X (R
θJC
+ R
θCS
+ R
θSA
) + T
A
Where
T
J
P
D
R
θJC
R
θCS
R
θSA
T
A
=
=
=
=
=
=
Junction Temperature
Total Power Dissipation
Junction to Case Thermal Resistance
Case to Heat Sink Thermal Resistance
Heat Sink to Ambient Thermal Resistance
Ambient Temperature
OUTPUT VOLTAGE SELECTION
As noted in the above typical applications circuit, the
formula for output voltage selection is
VOUT=1.265 1+ R1
R2
A good starting point for this output voltage selection is
to set R2=1K. By rearranging the formula it is simple to
calculate the final R1 value.
R1=R2 VOUT -1
1.265
Table 1 below lists some of the most probable resistor
combinations based on industry standard usage.
Power Dissipation=(VIN-VOUT) x I
OUT
Next, the user must select a maximum junction tem-
perature. The absolute maximum allowable junction tem-
perature is 150°C. The equation may now be rearranged
to solve for the required heat sink to ambient thermal
resistance (R
θSA
).
START UP CURRENT
The MSK 5821RH sinks increased current during startup
to bring up the output voltage. Reference the "Saturated
Drive Current vs. Input Voltage" graph in the typical per-
formance curves of this data sheet and the "Understand-
ing Startup Surge Current With MS Kennedy's RH1573
Based Rad Hard LDO Regulators" application note in the
application notes section of the MS Kennedy Web site
for more information.
http://www.mskennedy.com/
Example:
An MSK 5821RH is connected for VIN=+3.3V and
VOUT=+2.5V. I
OUT
is a continuous 3A DC level. The
ambient temperature is +25°C. The maximum desired
junction temperature is +125°C.
R
θJC
=4.0°C/W and R
θCS
=0.15°C/W for most thermal
greases
Power Dissipation=(3.3V-2.5V) x (3A)
=2.4Watts
Solve for R
θSA:
R
θSA
=
125°C - 25°C
- 2.9°C/W - 0.15°C/W
2.4W
TOTAL DOSE RADIATION TEST
PERFORMANCE
Radiation performance curves for TID testing have been
generated for all radiation testing performed by MS
Kennedy. These curves show performance trends through-
out the TID test process and can be located in the MSK
5810RH radiation test report. The complete radiation test
report is available in the RAD HARD PRODUCTS section
on the MSK website.
http://www.mskennedy.com/store.asp?pid=9951&catid=19680
Reference the MSK 5826RH RAD REPORT for ELDRS
and Neutron results.
4
= 38.6°C/W
In this example, a heat sink with a thermal resistance
of no more than 38.6°C/W must be used to maintain a
junction temperature of no more than 125°C.
Rev. G
1/11
TYPICAL PERFORMANCE CURVES
5
Rev. G
1/11
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