MIL-PRF-38534 AND 38535 CERTIFIED FACILITY
RAD HARD 2.0A
SWITCHING REGULATOR
M.S.KENNEDY CORP.
5053RH
4707 Dey Road Liverpool, N.Y. 13088
(315) 701-6751
FEATURES:
Manufactured using
Space Qualified RH3480 Dice
Total Dose Hardened 100 Krad (Method 1019.7 Condition A)
Programmable Fixed Frequency or Synchronizable up to 2MHz
2.0A Integrated Switch
Internal Slope Compensation
Input Voltage Range from 3.6V to 36V
Cycle by Cycle Current Limit
Output Voltages Down to 0.79V
External Compensation
Power Good Indicator
RUN/SS Pin for Power Sequencing and Rise Time Control
DESCRIPTION:
The MSK 5053RH is a radiation hardened 2MHz adjustable output voltage switching regulator. A wide input and output
voltage range with a 2.0A output current capability make these regulators suitable for a wide variety of applications. The
adjustable switching frequency allows the end user to select the frequency that maximizes the device performance in the
given application. The switching frequency can be fixed at a chosen frequency with a single resistor or synchronized via the
SYNC pin. The MSK 5053RH simplifies design of high efficiency radiation hardened switching regulators that use a minimum amount of board space. The MSK 5053RH is hermetically sealed in a 40 pin flatpack with straight or Gull wing leads
and is specifically designed for space/satellite applications.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
PIN-OUT INFORMATION
1-9
10
11
12-20
21
22
23
POL Applications
Satellite System Power Supply
Step Down Switching Regulator
Microprocessor, FPGA Power Source
High Efficiency low Voltage
Subsystems Power Supply
1
POWER GND
CASE
NC
VIN
SIGNAL GND
RUN/SS
SYNC
30-40
28-29
27
26
25
24
VOUT
BD
RT
COMP
FB
PGOOD
8548-28 Rev. D 10/13
ABSOLUTE MAXIMUM RATINGS
VIN
Input Voltage
RUN/SS Volatge
Output Current
BOOST Voltage
BOOST Above SW Voltage
FB, RT, VC Pin Voltage
PG, BD, SYNC Pin Voltage
ESD Rating
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IOUT
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9
TST Storage Temperature Range
-65°C to +150°C
TLD Lead Temperature Range
(10 Seconds)
300°C
TJ Junction Temperature
+150°C
PD Power Dissipation
2.4
TC Case Operating Temperature Range
MSK 5053K/H RH
-55°C to +125°C
MSK 5053RH
-40°C to +85°C
36V
36V
2.0A
56V
30V
5.0V
30V
Class 2
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7
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ELECTRICAL SPECIFICATIONS
NOTES:
Unless otherwise specified VIN=5V, VOUT=2.5V, VBD=VIN, IOUT=10mA, VPG=5V, RUN/SS=5V
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 subgroup 1 and 4 unless otherwise specified.
Military grade devices ("H" and "K" Suffix) shall be 100% tested to subgroups 1,2,3 and 4.
Subgroup 5 & 6 testing available on request.
Subgroup 1,4 TC=+25°C
2,5 TC=+125°C
3,6 TC=-55°C
7 Continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle.
8 Pre and Post irradiation limits, up to 100 Krad TID, are identical unless otherwise specified.
9 Internal solder reflow temperature is 180°C, do not exceed.
1
2
3
4
5
6
2
8548-28 Rev. D 10/13
APPLICATION NOTES
PIN FUNCTIONS
SYNC - The SYNC pin is the input for an external clock source
to control the regulators switching frequency. The recommended clock source is a square-wave with 20% to 80%
duty cycle. The clock source rise and fall times must be faster
than 1uS. The Synchronization range is from 250KHz to 2MHz.
The RT pin resistor must be set to a frequency which is 20%
below the lowest synchronized frequency. Reference the
PGOOD pin description. Tie the SYNC pin to ground when
not used.
VIN - The VIN pins connect to the collector of the internal
power switch and provide power to the internal control circuitry and internal regulator. Very high di/dt is seen at these
pins during switch on and off transitions. High frequency
decoupling capacitors are recommended to minimize voltage spikes. The VIN pins should be connected to a low
impedance source for best operation.
VOUT - The VOUT pins are the power output of the regulator. Output capacitance must be connected between the
VOUT pins and POWER ground to maintain stability and minimize output ripple voltage, see "Selecting the Output Capacitors". Provide a low impedance path between VOUT
and the load to minimize voltage drops.
PG - The PG pin is power good flag. It is an open collector
output that transitions from low to high when the output rises
to within 14% of it's programmed value.
RT - The RT pin is used to program the oscillator frequency.
A single resistor from RT to ground is all that is required to
program the oscillator frequency. Use the table below to select the require resistor for the desired switching frequency.
SIGNAL GND - The SIGNAL GND pin provides a return path
for all internal control current and acts as the reference to
the error amplifier. It is important that it is at the same
voltage potential as the load return to ensure proper regulation. Keep current on the ground between the load and the
MSK 5053RH to a minimum and use large copper traces to
minimize voltage drops an regulation error.
POWER GND- The POWER GND provides the high current
load return path to the MSK 5053RH's internal catch diode.
High speed switching transitions occur on the power ground
with every switching cycle. The load return current commutates between the input bus return and the POWER GND
pins. Place a minimum of 0.1uF to 1.0uF of high frequency
ceramic capacitance physically close to the POWER GND
and VIN pins to maximize performance.
BD- The BD pin connects to the anode of the internal boost
diode and supplies current to the internal regulator. Connect
BD to the VIN supply for typical applications. Slight efficiency improvements can be realized for applications with
high input voltages and output voltages greater than or equal
to 3.3V by connecting the BD pin to the output.
FB - The FB (feedback) pin's primary function is to set the
output voltage. Use a resistive divider from VOUT to GND
to set the voltage at the feedback pin to 0.79V when the
output voltage is at the desired level.
Switching Frequency
Resistor Value
200KHz
300KHz
187KΩ
121KΩ
400KHz
500KHz
600KHz
700KHz
88.7KΩ
68.1KΩ
800KHz
40.2KΩ
900KHz
1.0MHz
1.2MHz
34KΩ
29.4KΩ
23.7KΩ
1.4MHz
19.1KΩ
1.6MHz
16.2KΩ
1.8MHz
2.0MHz
13.3KΩ
11.5KΩ
56.2KΩ
46.4KΩ
SETTING THE OUTPUT VOLTAGE
The output voltage of the MSK 5053RH is set with a simple
resistor divider network: see Figure 1 (Typical Application
Circuit). Select the resistor values to divide the desired output down to equal VREF (0.790V nominal) at the FB pin.
COMP - The COMP pin is the output of the error amplifier
and the input of the peak current comparator. This pin is
used for frequency compensation. Tie an RC network between the VC pin and ground to adjust the frequency response of the loop.
VOUT=VREF*(1+R1/R2)
R1=R2*(VOUT/VREF-1)
RUN/SS - The RUN/SS pin has two shutdown functions. The
first function disables the regulator when the voltage on the
pin is pulled low. Tie to 2.5V or greater for normal operation. The second function is softstart. Use an RC network
to control the rise time of the RUN/SS pin to limit the rise
time of the current supplied to the load. The resistor must
be chosen such that the RUN/SS pin will rise above and
remain above 2.5V under all operating conditions and while
sourcing the RUN/SS pin worst case sink current.
3
8548-28 Rev. D 10/13
APPLICATION NOTES CONT'D
SELECTING THE SWITCHING FREQUENCY
COMPENSATING THE LOOP
The MSK 5053RH can be set to operate over a frequency
range of 400KHz to 2.0MHz but 800KHz to 1MHz works
well for most applications. The output ripple voltage and
efficiency will vary with frequency and input voltage. Higher
frequency increases switching losses but reduces output
current ripple and core losses while lower frequency reduces switching losses and increases output current ripple
and core losses. Higher voltages tend to increase output
current ripple so higher frequencies may be preferred to
reduce the ripple in applications in higher voltage applications. Care must be taken when increasing the frequency
to ensure that the required switch on time is greater than
the control circuit's minimum on time for low noise systems, the same is true for the minimum off time. The
output will still regulate if the minimum on or off time is
violated but the output ripple will increase. The typical
minimum off time is 60nS. Reference the minimum on time
curve in the typical performance curves section for typical minimum on time information.
The current mode power stage from the VC node to the SW
node can be modeled as a transconductance of gm=3.5A/V.
The DC output gain will be the transconductance times the load
resistance. As frequency increases the output capacitance rolls
off the gain until the ESR zero is reached. The error amplifier
can be modeled as a transconductance of 400u-mho with an
output impedance of about 3M-ohm. Typically a single RC network from VC to ground works well for applications with mostly
ceramic capacitance. An additional capacitor from VC to ground
may be needed to cancel the ESR zero in applications with mostly
tantalum bulk capacitance.
LOW RIPPLE BURST MODE
The MSK 5053RH can be operated in low ripple burst mode to
maximize efficiency at very light loads. In low ripple burst mode
the control circuitry delivers single bursts of current to maintain regulation followed by periods of no switching or sleep periods. The quiescent current draw is minimized during the sleep
periods increasing overall efficiency. Tie the SYNC pin to ground
to enable low ripple burst mode at light loads. Low ripple burst
mode is not available when using the SYNC feature. If the MSK
5053RH is being synchronized to an external clock source the
control circuitry will skip pulses at light loads to improve efficiency.
SELECTING THE OUTPUT CAPACITOR
The output capacitor filters the ripple current from the
inductor to an acceptable ripple voltage seen by the load.
The primary factor in determining voltage ripple is the ESR
of the output capacitor. The voltage ripple can be approximated as follows:
TOTAL DOSE RADIATION TEST
PERFORMANCE
VP-P=IP-P*ESR
Radiation performance curves for TID testing have been generated for all radiation testing performed by MS Kennedy. These
curves show performance trends throughout the TID test process and can be located in the MSK 5053RH radiation test report. The complete test report is available in the RAD HARD
PRODUCTS section of the MSK website.
The typical ESR range for an MSK 5053RH application is
between 0.05 and 0.20 ohm. Capacitors within these ESR
ranges typically have enough capacitance value to make
the capacitive term of the ripple equation insignificant.
The capacitive term of the output voltage ripple lags the
ESR term by 90° and can be calculated as follows:
ADDITIONAL APPLICATION INFORMATION
For additional applications information, please reference Linear
Technology's® LT3480 data sheet.
VP-P(CAP)=IP-P/(8*F*C)
Where
C=Output capacitance in Farads
TYPICAL APPLICATION CIRCUIT
Select a capacitor or combination of capacitors that can
tolerate the worst-case ripple current with sufficient derating. When using multiple capacitors in parallel to achieve
ESR and/or total capacitance, sharing of ripple current
between capacitors will be approximately equal if all of
the capacitors are the same type and preferably from the
same lot. Low ESR tantalum capacitors are recommended
over aluminum electrolytic. The zero created by the ESR
of the capacitor is necessary for loop stabilty. A small
amount of ceramic capacitance close to the load to
decouple high frequency is acceptable but it should not
cancel the ESR zero. Additional ceramic capacitance may
be required at switching frequencies above 1MHz where
some tantalum capacitors begin to act inductive.
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8548-28 Rev. D 10/13
TYPICAL PERFORMANCE CURVES
5
8548-28 Rev. D 10/13
TYPICAL PERFORMANCE CURVES CONT'D
GAIN AND PHASE RESPONSE
The gain and phase response curves are for the MSK typical application circuit and are representative of typical device
performance, but are for reference only. The performance should be analyzed for each application to insure individual
program requirements are met. External factors such as temperature, input and output voltages, capacitors, etc. all can be
major contributors. Please consult factory for additional details.
6
8548-28 Rev. D 10/13
MECHANICAL SPECIFICATIONS
ESD TRIANGLE INDICATES PIN 1
WEIGHT=12.2 GRAMS TYPICAL
ORDERING INFORMATION
PART NUMBER
SCREENING LEVEL
MSK5053RH
INDUSTRIAL
MSK5053HRH
MIL-PRF-38534 CLASS H
MSK5053KRH
MIL-PRF-38534 CLASS K
7
LEADS
STRAIGHT
8548-28 Rev. D 10/13
MECHANICAL SPECIFICATIONS
ESD TRIANGLE INDICATES PIN 1
WEIGHT=12.2 GRAMS TYPICAL
ORDERING INFORMATION
PART NUMBER
SCREENING LEVEL
MSK5053RHG
INDUSTRIAL
MSK5053HRHG
MIL-PRF-38534 CLASS H
MSK5053KRHG
MIL-PRF-38534 CLASS K
LEADS
GULL
WING
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.
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8548-28 Rev. D 10/13