MIL PRF 38534 CERTIFIED
M.S.KENNEDY CORP.
RAD TOLERANT ULTRA LOW
DROPOUT ADJUSTABLE
POSITIVE LINEAR REGULATOR
5921RH
4707 Dey Road Liverpool, N.Y. 13088
(315) 701-6751
FEATURES:
Total Dose Tested to 300K RAD
Ultra Low Dropout for Reduced Power Consumption
External Shutdown
Latching Overload Protection
Adjustable Output Using Two External Resistors
Output Current Limit
Available in 3 Lead Form Options: Straight, Up and Down
Available to DSCC SMD # 5962-05220
DESCRIPTION:
The MSK 5921RH is a rad tolerant adjustable linear regulator typically capable of delivering 5.0 amps of output
current. The typical dropout is only 0.30 volts with a 3.0A 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 5921RH is radiation tolerant 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
PIN-OUT INFORMATION
TYPICAL APPLICATIONS
Satellite System Power Supplies
Switching Power Supply Post Regulators
Constant Voltage/Current Regulators
Microprocessor Power Supplies
1
2
3
4
5
1
VIN
GND
VOUT
SHUTDOWN
ADJUST
Rev. C
1/06
ABSOLUTE MAXIMUM RATINGS
+VIN
IOUT
TC
8
Supply Voltage
+10V
Output Current 7
5A
Case Operating Temperature Range
MSK5921K/H/E RH
-55°C to +125°C
MSK5921RH
-40°C to +85°C
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TST
TLD
PD
TC
Storage Temperature Range -65°C to +150°C
Lead Temperature Range
300°C
(10 Seconds)
Power Dissipation
See SOA Curve
Junction Temperature
150°C
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ELECTRICAL SPECIFICATIONS
Group A
Test Conditions 1 11
Parameter
Input Voltage Range 2
Feedback Voltage
10mA ≤ IOUT ≤ 1.0A
MSK5921K/H/E
Subgroup
Min.
1
Typ.
Min.
2.9
6.5
2.9
2,3
2.9
6.5
1.265
1
1.225
2,3
1.225
1.305
VFB=1.265V 10mA ≤ IOUT ≤ 3.0A
1,2,3
0
5.0
VIN=6.5V
1
Not Including IOUT
2,3
IOUT=50mA
1
VOUT+0.4V ≤ VIN ≤ IOUT+1.3V
2,3
Load Regulation 9
10mA ≤ IOUT ≤ 3.0A
1
Dropout Voltage 10
Delta FB=1% IOUT=2.5A
IOUT=3.0A R1=187Ω
Feedback Pin Current 2
Quiescent Current
Line Regulation 9
20
14
20
Output Voltage Range 2
Output Current Limit
7
Shutdown Threshold
Ripple Rejection 2
6.5
1.265
1.328
0
14
µA
20
mA
±0.60 %VOUT
%VOUT
0.06
±1.0 %VOUT
0.22
0.45
%VOUT
±0.80
2,3
0.26
0.40
2.8V ≤ VIN ≤ 6.5V
1
8
10
R1=187Ω
2,3
9
1.5
8
10
1.5
3.0
4.0
5.0
2,3
3.0
4.0
5.0
VOUT ≤ 0.2V (OFF)
1
1.0
1.3
1.6
VOUT=Nominal (ON)
2,3
1.0
1.3
1.6
f=120Hz
4
65
IOUT =50mA
mA
mA
10
3.0
V
V
6.0
1
V
mA
0.01
±0.06 ±0.80
0.40
V
5.0
±0.50
0.22
VIN=3.5V VOUT=2.5V
Units
Max.
V
±0.01 ±0.50
1
VIN=6.5V
Typ.
V
1.305 1.202
14
2,3
Minimum Output Current 2
MSK5921
Max.
4.0
6.0
V
5.0
A
A
1.0
1.3
1.6
V
V
65
dB
5,6
65
Phase Margin 2
4,5,6
30
70
30
70
degrees
Gain Margin 2
4,5,6
10
18
10
18
dB
Equivalent Noise Voltage 2
Thermal Resistance 2
dB
4,5,6
Referred to Feedback Pin
Junction to Case @ 125°C Output Device
50
2.2
4.0
2.2
50
µVRMS
4.0
°C/W
NOTES:
1
2
3
4
5
6
7
8
9
10
11
Unless otherwise specified, VIN=5.0V, R1=1.62K, VSHUTDOWN=0V and IOUT=10mA. See Figure 2.
Guaranteed by design but not tested. Typical parameters are representative of actual device performance but are for reference only.
Industrial grade and "E" suffix 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 TC=+25°C
Subgroup 2,5 TC=+125°C
Subgroup 3,6 TA= 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.
VIN shall be as specified or VIN Min, whichever is greater.
Not applicable when VOUT<VIN Min dropout voltage maximum.
Consult factory for post radiation limits.
2
Rev. C
1/06
APPLICATION NOTES
PIN FUNCTIONS
OUTPUT CAPACITOR SELECTION
Output capacitors are required to maintain regulation
and stability. A 220µF surface mount tantalum capacitor
in parallel with a 1.0µF ceramic capacitor from the output to ground should suffice under most conditions. 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. ESR of the output capacitors should
be maintained at 0.1Ω to 1Ω.
VIN - This pin provides power to all internal circuitry
including 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 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 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 connected to an internal 1.265V reference. This error amplifier 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.
OVERCURRENT LATCH
Overcurrent protection is provided by the MSK5921RH
series through the use of a timed latch off circuit. The
internal latch timeout is triggered by an overcurrent condition. To allow for start up surge currents, the timeout
is approximately 5.5mS at 25°C. If the overcurrent condition remains at the end of the timeout cycle, the regulator will latch off until the latch is reset. The latch condition can be reset 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 5921RH current limit function is directly affected by the input and output voltages. Figure 1 illustrates the relationship between VIN and ICL for various
output voltages. It is very important for the user to consult the SOA curve when using input voltages which
result 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 a 100µF tantalum capacitor is connected between VIN and ground. A
0.1µF ceramic capacitor should also be used for high
frequency bypassing.
3
Rev. C
1/06
APPLICATION NOTES CONT.
THERMAL LIMITING
The MSK 5921RH control circuitry has a thermal shutdown temperature of approximately 150°C. This thermal 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 conditions.
TYPICAL APPLICATIONS CIRCUIT
HEAT SINK SELECTION
To select a heat sink for the MSK 5921RH, the following formula for convective heat flow may be used.
Governing Equation:
TJ = PD X (RθJC + RθCS + RθSA) + TA
Where
TJ
PD
RθJC
RθCS
RθSA
TA
=
=
=
=
=
=
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
R1
VOUT=1.265 1+
R2
Power Dissipation=(VIN-VOUT) x IOUT
Next, the user must select a maximum junction temperature. The absolute maximum allowable junction temperature is 150°C. The equation may now be rearranged
to solve for the required heat sink to ambient thermal
resistance (RθSA).
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.
Example:
Table 1 below lists some of the most probable resistor
combinations based on industry standard usage.
An MSK 5921RH is connected for VIN=+3.3V and
VOUT=+2.5V. IOUT is a continuous 3A DC level. The ambient temperature is +25°C. The maximum desired junction temperature is +125°C.
R1=R2
VOUT -1
1.265
TABLE 1
RθJC=4.0°C/W and RθCS=0.15°C/W for most thermal
greases
Power Dissipation=(3.3V-2.5V) x (3A)
=2.4Watts
Solve for RθSA:
RθSA= 125°C - 25°C -4.0°C/W - 0.15°C/W
2.4W
= 36.5°C/W
In this example, a heat sink with a thermal resistance
of no more than 36.5°C/W must be used to maintain a
junction temperature of no more than 125°C.
4
OUTPUT
VOLTAGE
(V)
R2
(Ω
Ω)
R1 (nearest 1%)
(Ω
Ω)
1.5
1K
187
1.8
1K
422
2.0
1K
576
2.5
1K
976
2.8
1K
1.21K
3.3
1K
1.62K
4.0
1K
2.15K
5.0
1K
2.94K
Rev. C
1/06
TYPICAL PERFORMANCE CURVES
5
Rev. C
1/06
RADIATION PERFORMANCE CURVES
NOTE: All radiation performance curve test conditions are in accordance with the electrical specifications table (page 2).
6
Rev. C
1/06
MECHANICAL SPECIFICATIONS
WEIGHT=7.7 GRAMS TYPICAL
ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.
ESD Triangle indicates pin 1.
ORDERING INFORMATION
MSK5921 K RH U
LEAD CONFIGURATIONS
S= STRAIGHT; U= BENT UP; D= BENT DOWN
RADIATION HARDENED
SCREENING
BLANK= INDUSTRIAL; E=EXTENDED RELIABILITY
H=MIL-PRF-38534 CLASS H; K= MIL-PRF-38534 CLASS K
GENERAL PART NUMBER
The above example is an adjustable Class K regulator with leads bent up.
NOTE: See DSCC SMD 5962-05220 for DSCC part number options.
M.S. Kennedy Corp.
4707 Dey Road, Liverpool, New York 13088
Phone (315) 701-6751
FAX (315) 701-6752
www.mskennedy.com
The information contained herein is believed to be accurate at the time of printing. MSK reserves the right to make
changes to its products or specifications without notice, however, and assumes no liability for the use of its products.
Please visit our website for the most recent revision of this datasheet.
Contact MSK for MIL PRF 38534 Class H, Class K and Appendix G (radiation) status.
7
Rev. B 11/05