ISO-9001 CERTIFIED BY DSCC
M.S.KENNEDY CORP.
FEATURES:
RADIATION HARDENED
HIGH EFFICIENCY, 4 AMP
SWITCHING REGULATORS
5046RH
SERIES
(315) 701-6751
4707 Dey Road Liverpool, N.Y. 13088
Up To 92% Conversion Efficiency For 5V Version
4 Amp Output Current
3.1V to 18V Input Range with Startup Bias
12V to 18V Input Range with UVLO (VBias=V
IN
)
Preset 1.5V, 2.5V, 3.0V, 3.3V or 5.0V Output Versions
Custom Output Voltages Available
300KHz Switching Frequency
Hermetic Package with Three Lead Form Options
-55°C to +125°C Operating Temperature Range
Total Dose Rated to TBDK RAD
MIL-PRF-38534 CERTIFIED
DESCRIPTION:
The MSK 5046RH series are high efficiency, 4 amp, radiation hardened switching regulators. The output voltage is
configured for 1.5V, 2.5V, 3.0V, 3.3V or 5.0V internally with a tolerance of 1% at 1.5 amps. The operating frequency
of the MSK 5046RH is 300KHz. A low quiescent current and greater than TBD operating efficiency keep the total
internal power dissipation of the MSK 5046RH down to an absolute minimum. The device is packaged in a hermetic
power package for high reliability applications, and is available fully compliant to MIL-PRF-38534 Class H or K.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
Step-down Switching Regulator
Microprocessor, FPGA Power Source
High Efficiency Low Voltage
Subsystem Power Supply
1
2
3
4
5
6
1
PIN-OUT INFORMATION
COMP
ENABLE
VBOOT
VBIAS
VIN
VIN
12
11
10
9
8
7
SENSE
VOUT
VOUT
VOUT
RETURN
RETURN
PRELIMINARY Rev. B 11/03
ABSOLUTE MAXIMUM RATINGS
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ELECTRICAL SPECIFICATIONS
NOTES:
V
IN
=12V, VBias=12V, I
OUT
=1.5A unless otherwise specified.
Guaranteed by design but not tested. Typical parameters are representative of actual device performance but are for reference only.
All output parameters are tested using a low duty cycle pulse to maintain T
J
= T
C
.
Industrial grade and 'E' suffix devices shall be tested to subgroup 1 unless otherwise specified.
Military grade devices ('H' and 'K' suffix) shall be 100% tested to subgroups 1,2,3 and 4.
Subgroup 1
Subgroup 2
Subgroup 3 T
A
=T
C
=+25°C
8 Alternate output =T
C
=+125°C
T
A
voltages are available. Please contact the factory.
9 VBoot is measured with a 40mA load on the VBoot pin.
T
A
=T
C
=-55°C
10 The device can operate with input voltages as high as 18V, but efficiency is best at lower inputs.
11 With VBias connected to a separate source, V
IN
Min. is approximately 3.1V.
12 Contact factory for post radiation limits.
13 Includes VBias power consumption.
1
2
3
4
5
6
2
PRELIMINARY Rev. B 11/03
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T
J
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Input Voltage
Enable
Output Current
Thermal Resistance (@ 125°C)
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-0.3V, +20V
-0.3V, 10.5V
4.0 Amps
10°C/W
T
ST
T
LD
T
C
Storage Temperature Range
Lead Temperature Range
(10 Seconds)
Case Operating Temperature
MSK5046RH Series
MSK5046RH K/H/E Series
Junction Temperature
-65°C to +150°C
300°C
-40°C to +85°C
-55°C to +125°C
+150°C
APPLICATION NOTES
INPUT BIAS AND UVLO:
The VBias pin of the MSK 5046RH provides bias to the con-
trol circuitry. The Vbias pin can be connected directly to the
input bus for 12V to 16V operation or it can be biased sepa-
rately with a 12V to 16V source to extend the input range of
the device refer to the paragraph titled "INPUT VOLTAGE
RANGE". The MSK 5046RH's built in under voltage lockout
feature prevents damage to downstream devices in the event
of a drop in bias voltage. Under voltage lockout occurs at bias
voltages of approximately 10.3V rising and 9.5V falling. The
internal bias draws approximately 40mA under normal opera-
tion.
OUTPUT CAPACITOR SELECTION:
The MSK 5046RH has an internal 0.1µF ceramic ca-
pacitor between VOUT and RETURN. An additional 1µF
of ceramic capacitance on the output will help suppress
the high frequency switching noise. Use between 100
and 300µF of low ESR bulk capacitance for optimum
performance. Larger output capacitance may require ad-
ditional loop compensation, refer to the paragraph titled
"Compensation".
SENSE:
INPUT VOLTAGE RANGE
The MSK 5046RH's input range of 12V to 16V can be fur-
ther extended down to 3.1V by using a separate bias supply.
In this configuration very efficient low V to low V conversion
can be achieved.
BOOTSTRAPPING:
The MSK 5046RH's Vboot output can be used to supply
bias voltage once the device is operating. Use a diode to "OR"
the startup bias supply with the Vboot output if the startup
supply voltage is less than Vboot. Use a switching scheme if
Vboot is less than or equal to Vstartup. Additional bypass
capacitance is required on the Vbias input pin when
bootstrapping the MSK 5046RH. Since the bootstrap voltage
is stepped up from the output voltage, it will vary with load.
Any voltage drop between the output and the sense pin will
increase the bootstrap voltage. Direct biasing of the VBias
input may be more efficient due to the additional conversion
involved in bootstrapping.
It is very important that the DC voltage returned to the
SENSE pin from the output be as noise and oscillation
free as possible. This voltage helps to determine the final
output and therefore must be a clean voltage. Excessive
noise or oscillation can cause the device to have an incor-
rect output voltage. Proper PC board layout techniques
can help to achieve a noise free voltage at the SENSE
pin.
ENABLE FUNCTION:
The ENABLE pin of the MSK 5046RH is designed for
open collector drive. Leaving the pin open will allow for
normal operation. Pulling the pin low will shut the de-
vice down.
INPUT CAPACITOR SELECTION:
The MSK 5046RH should have an external high frequency
ceramic capacitor (0.1uF) between VIN and GND. Connect a
low-ESR bulk capacitor directly to the input pin of the MSK
5046RH. Select the bulk input filter capacitor according to
input ripple-current requirements and voltage rating, rather than
capacitor value. Electrolytic capacitors that have low enough
ESR to meet the ripple-current requirement invariably have more
than adequate capacitance values. Aluminum-electrolytic ca-
pacitors are preferred over tantalum types, which could cause
power-up surge-current failure when connecting to robust AC
adapters or low-impedance batteries.
COMPENSATION:
When driving large capacitive loads it may be neces-
sary to connect a 10 to 20nF ceramic capacitor between
the V
SENSE
pin and the COMP pin. This will add a zero/
pole pair to the overall loop transfer function to prevent
oscillation and improve bandwidth.
3
PRELIMINARY Rev. B 11/03
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