MSK5950ERH - M.S. Kennedy Corp. - Datasheet.Directory

VOUTE

VOUTD

VOUTC

VOUTB

VOUTA

VREF

GND2

TYPICAL APPLICATIONS

4707 Dey Road Liverpool, N.Y. 13088 (315) 701-6751

MIL-PRF-38534 CERTIFIED 5950RH

M.S.KENNEDY CORP.

FEATURES:

Satellite System Power Supplies

Switching Power Supply Post Regulators

Constant Voltage/Current Regulators

Microprocessor Power Supplies

RAD HARD ULTRA LOW

VOLTAGE ADJUSTABLE

POSITIVE LINEAR REGULATOR

EQUIVALENT SCHEMATIC

TYPICAL APPLICATIONS

DESCRIPTION:

The MSK 5950RH is a radiation hardened adjustable linear regulator capable of delivering 5.0 amps of output current.

The typical dropout is only 0.11 volts at 1 amp. An external shutdown/reset function is ideal for power supply sequencing.

This device also has latching overload protection that requires no external current sense resistor. The MSK 5950RH is

radiation hardened and specifically designed for many space/satellite applications. The device is packaged in a hermetically

sealed 20 pin flatpack that can be lead formed for surface mount applications.

PIN-OUT INFORMATION

VINA

VINB

VINC

VIND

VINE

VBIAS

GND1

Latch

Shutdown

Manufactured using Space Qualified RH1009 and RH1573 Die

Total Dose Tested to 450 Krad (Method 1019.7 Condition A)

Output Adjustable Down to Near Zero

External Shutdown/Reset Function

Latching Overload Protection

Adjustable Output Using External Resistors

Output Current Limit

Surface Mount Package Available with Lead Forming

Low Input Voltage for Maximum Efficiency

Up to 5A Output Current

Contact MSK for MIL-PRF-38534 Qualification Status

10 Rev. C 12/091

Storage Temperature Range

Lead Temperature Range

(10 Seconds)

Power Dissipation

Junction Temperature

ABSOLUTE MAXIMUM RATINGS

10.0V

20mA

-55°C to +125°C

-40°C to +85°C

Bias Supply Voltage

Supply Voltage

Reference Sink Current

Output Current

Case Operating Temperature Range

MSK5950K/H/E RH

MSK5950RH

-65°C to +150°C

300°C

See SOA Curve

150°C

TST

TLD

+VBIAS

+VIN

IVREF

IOUT

Unless otherwise specified

, VBIAS=VIN=3.3V, R1=61.9Ω, RREF=249Ω (see figure 1), VSHUTDOWN=0V and IOUT=10mA.

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 tested with a low duty cycle pulse to minimize junction heating and is dependent on the values of VIN, VOUT and case

temperature. See Typical Performance Curves.

Continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle.

Pre and post irradiation limits @25°C, up to 300 Krad TID, are identical unless otherwise specified.

NOTES:

○○○○○○○○○○○○○○ ○○○○○○○○○

○○○ ○○○○○○○○

○○○○

ELECTRICAL SPECIFICATIONS

○○○○○○○○○

○○○○○○○○○○○○○○○○ ○○○○○○○○

○○○○○○○○○○○

○○○○○○○○

Rev. C 12/09

APPLICATION NOTES

VIN A,B,C,D,E - These pins provide the input power connection

to the MSK 5950RH. This is the supply that will be regulated to

the output. All five pins must be connected for proper operation.

VBIAS - This pin provides power to all internal circuitry including

bias, start-up, thermal limit and overcurrent latch. VBIAS voltage

range is 2.9V to 7.5V. VBIAS should be kept greater than or

equal to VIN.

VREF - Internal general purpose 2.5V shunt regulator that will

operate over a wide current range while maintaining good stabil-

ity. This reference voltage is used along with the feedback volt-

age to configure the desired output voltage. The reference will

maintain good regulation as long as 0.4≤ISHUNT≤10mA. The

shunt current is derived from a resistor tied to VIN or VBIAS. The

resistor must supply both the minimum shunt current of 400µA

(1mA recommended) and the current required by the output volt-

age feedback divider network, between 2 and 2.5mA total is

typically sufficient. A constant current diode (CCR) may be used

in place of the resistor to minimize variations in ISHUNT due to

line voltage variations.

Resistor calculation example:

VBIAS=3.3V±10%

VOUT=0.9V

First determine the required current by selecting R2 in the feed

back divider, typically between 1.0 and 1.2KΩ; see the output

voltage selection paragraph. Using standard value 0.1% toler-

ance resistors, the nominal output will be 0.9V with R2=1.07K

and R1=316Ω. The current in the divider will be equal to (VREF-

VFDBK)/R2 or 1.154mA nominal and 1.2mA worst-case in this

example.

The total current required is the sum of the worst-case divider

current plus the VREF shunt current. The minimum shunt current

is 400µA but 1mA is recommended. Using the recommended

1mA the minimum current required in RREF is 2.2mA.

The maximum resistor value to source the required current is

equal to (VBIAS min-VREF)/2.2mA or 218Ω for this example.

The maximum current in the reference must not exceed 10mA,

the absolute maximum allowable bias voltage is

10mA*RREF+VREF(min) or 4.67V for this application.

The designer must also consider that the feedback divider will

provide a resistive connection from the source (VIN or VBIAS) to

the output even when the regulator is disabled. A minimum load

resistor can be used to draw the voltage down in the event this

poses a problem. A 90Ω resistor will sink 10mA during opera-

tion and pull the output well below 200mV when the regulator is

disabled in this application.

VREF can be used as a precision 2.5V reference for other parts of

the circuit as long as circuit loading, shunt current and parasitics

are carefully considered.

GND1 - Internally connected to input ground, these pins should

be connected externally by the user to the circuit ground and the

GND2 pins.

VOUT A,B,C,D,E - These are the output pins for the device. All

five pins must be connected for proper operation.

GND2 - Internally connected to output ground, these pins should

be connected externally by the user to the circuit ground and the

GND1 pins. 3

PIN FUNCTIONS

Rev. C 12/09

LATCH - The MSK 5950RH LATCH pin is used for both current

limit and thermal limit. A capacitor between the LATCH pin and

ground sets a time out delay in the event of an over current or

short circuit condition. The capacitor is charged to approximately

1.6V from a 7.2µA (nominal) current source. Exceeding the ther-

mal limit will charge the latch capacitor from a larger current

source for a near instant shutdown. Once the latch capacitor is

charged the device latches off until the latch is reset. Momen-

tarily pull the LATCH pin low, toggle the shutdown pin high

then low or cycle the power to reset the latch. Toggling the

shutdown pin or cycling the bias power both disable the device

during the reset operation (see SHUTDOWN pin description).

Pulling the LATCH pin low immediately enables the device for as

long as the LATCH pin is held low plus the time delay to re-

charge the latch capacitor whether or not the fault has been

corrected. Disable the latch feature by tying the LATCH pin low.

With the LATCH pin held low the thermal limit feature is dis-

abled and the current limit feature will force the output voltage

to droop but remain active if excessive current is drawn.

SHUTDOWN - There are two functions to the SHUTDOWN pin.

It may be used to disable the output voltage or to reset the

LATCH pin. To activate the shutdown/reset functions the user

must apply a voltage greater than 1.3V 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.

FB - The FB pin is the inverting input of the internal error ampli-

fier. The non-inverting input is connected to an internal 1.265V

reference. This error amplifier controls the drive to the output

transis

tor to force the FB pin to 1.265V. An external resistor

divider is

connected to the output, FB pin, VREF and VIN to

set the output

voltage.

POWER SUPPLY BYPASSING

To maximize transient response and minimize power supply

transients it is recommended that a 33µF minimum tantalum

capacitor is connected between VIN and ground. A 0.1µF ce-

ramic capacitor should also be used for high frequency by-

passing.

Typically, large bulk capacitance is required at the output of a

linear regulator to maintain good load transient response. How-

ever, with the MSK 5950RH this is not the case. A 47µF sur-

face mount tantalum capacitor in parallel with a 0.1µF 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. See typical gain and phase curves.

OUTPUT CAPACITOR SELECTION

THERMAL LIMITING

The MSK 5950RH control circuitry has a thermal shutdown

temperature of approximately 150°C. This thermal shutdown

can be used as a protection feature, but for continuous opera-

tion, the junction temperature of the pass transistor must be

maintained below 150°C. Proper heat sink selection is essen-

tial to maintain these conditions. Exceeding the thermal limit

activates the latch feature of the MSK 5950RH. See LATCH pin

description for instructions to reset the latch or disable the latch

feature.

APPLICATION NOTES CONT.

4 Rev. C 12/09

START UP OPTIONS

The MSK 5950RH starts up and begins regulating immediately

when VBIAS and VIN are applied simultaneously. Applying VBIAS

before VIN starts the MSK 5950RH up in a disabled or latched

state. When starting in a latched state the device output can be

enabled either by pulling the latch pin low to drain the latch capaci-

tor or pulsing the shutdown pin high. The shutdown pulse dura-

tion is partially dependent upon the size of the latch capacitor and

should be characterized for each application; 30uS is typically ad-

equate for a 1uF latch capacitor at 25°C. A momentary high pulse

on the shutdown pin can be achieved using the RC circuit below if

VIN rises rapidly. The resistor and capacitor must be selected based

on the required pulse duration, the rise characteristic of VIN and

the shutdown pin threshold (see shutdown pin threshold and cur-

rent curves).

The shutdown pin can be held high and pulled low after VIN comes

up or the latch pin held low and released after VIN comes up to

ensure automatic startup when applying VBIAS before VIN. Either

of the basic circuits below can be adapted to a variety of applica-

tions for automatic start up when VBIAS rises before VIN.

HEAT SINK SELECTION

To select a heat sink for the MSK 5950RH, the follow-

ing formula for convective heat flow may be used.

Governing Equation:

TJ = PD X (RθJC + RθCS + RθSA) + TA

Where

TJ= Junction Temperature

PD= Total Power Dissipation

RθJC = Junction to Case Thermal Resistance

RθCS = Case to Heat Sink Thermal Resistance

RθSA = Heat Sink to Ambient Thermal Resistance

TA= Ambient Temperature

Power Dissipation=(VIN-VOUT) x IOUT

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 re-

sistance (RθSA).

Example:

An MSK 5950RH is connected for VIN=+3.3V and

VOUT=+1.2V. IOUT is a continuous 1A DC level. The am-

bient temperature is +25°C. The maximum desired junc-

tion temperature is +125°C.

RθJC=8.4°C/W and RθCS=0.15°C/W for most thermal

greases Power Dissipation=(3.3V-1.2V) x (1A)

=2.1Watts

Solve for RθSA:

125°C - 25°C

2.1W

= 39°C/W

In this example, a heat sink with a thermal resistance

of no more than 39°C/W must be used to maintain a junc-

tion temperature of no more than 125°C.

RθSA= -8.4°C/W - 0.15°C/W

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 are located in the MSK

5950RH radiation test report. The complete radiation test

report is available in the RAD HARD PRODUCTS section

on the MSK website.

TOTAL DOSE RADIATION TEST

PERFORMANCE

OVERCURRENT LATCH-OFF/LATCH PIN

CAPACITOR SELECTION

As previously mentioned, the LATCH pin provides over current/

output short circuit protection with a timed latch-off circuit. Refer-

ence the LATCH pin description note. The latch off time out is

determined with an external capacitor connected from the LATCH

pin to ground. The time-out period is equal to the time it takes to

charge this external capacitor from 0V to 1.6V. The latch charging

current is provided by an internal current source. This current is a

function of bias voltage and temperature (see latch charging current

curve). For instance, at 25°C, the latch charging current is 7.2µA

at VBIAS=3V and 8µA at VBIAS=7V.

In the latch-off mode, some additional current will be drawn from

the bias supply. This additional latching current is also a function

of bias voltage and temperature (see typical performance curves).

The MSK 5950RH current limit function is directly affected by

the input and output voltages. Custom current limit is available;

contact the factory for more information. http://www.mskennedy.com/store.asp?pid=9951&catid=19680

APPLICATION NOTES CONT.

OUTPUT VOLTAGE SELECTION

The MSK 5950RH output voltage can be adjusted from 0 to 2V.

Three different resistor network schemes are used depending on

the required output voltage level.

For output voltages below the minimum feedback voltage toler-

ance of 1.225V, R3 as shown in Figure 1 can be omitted. Out-

put voltage can be calculated as follows:

Given:

VFB=1.265V

VREF=2.5V

VOUT=VFB-((VREF-VFB)/R2)R1

For convenience Table 1 below provides standard 0.1% toler-

ance resistor values required to achieve several output voltages

based on nominal feedback voltage, R3 is ommitted.

TYPICAL APPLICATIONS CIRCUIT

FIGURE 1

Rev. C 12/09

FIGURE 2

For output voltages above the feedback voltage the unit should

be configured as shown in Figure 2.

For output voltages close to the feedback voltage tolerance of

1.225V-1.305V, a three resistor network may be used to im-

prove adjustment capabilities and trim out initial feedback volt-

age tolerances. Reference Figure 1.

VOUT= (R2R3VFB+R1R3(VFB-VREF)+R1R2VFB)/(R2R3)

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 set to

R2=1K. By rearranging the formula it is simple to calculate the

final R1 value.

R1=R2((VOUT/1.265)-1)

Table 3 below lists some of the most probable resistor combina-

tions based on industry standard usage, R3 is ommitted.

VOUT=1.265(1+R1/R2)

VREF can be used as a precision 2.5V reference as long as circuit

loading and shunt current are carefully considered. If VREF is not

used the pin should be pulled to ground.

TYPICAL PERFORMANCE CURVES

6 Rev. C 12/09

TYPICAL PERFORMANCE CURVES

Rev. C 12/09

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.

INDUSTRIAL

EXTENDED RELIABILITY

NOTE: ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.

ESD Triangle indicates pin 1.

ORDERING INFORMATION

MSK5950RH

MSK5950ERH

MSK5950HRH

SCREENING LEVEL

MIL-PRF-38534 CLASS H

MIL-PRF-38534 CLASS K

MSK5950KRH

WEIGHT=3.5 GRAMS TYPICAL

MECHANICAL SPECIFICATIONS

LEADS

STRAIGHT

PART NUMBER

Rev. C 12/09

ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.

ESD Triangle indicates pin 1.

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 status.

M.S. Kennedy Corp.

4707 Dey Road, Liverpool, New York 13088

Phone (315) 701-6751

FAX (315) 701-6752

www.mskennedy.com

ORDERING INFORMATION

WEIGHT=3.3 GRAMS TYPICAL

MECHANICAL SPECIFICATIONS CONTINUED

INDUSTRIAL

EXTENDED RELIABILITY

MSK5950RHG

MSK5950ERHG

MSK5950HRHG

SCREENING LEVEL

MIL-PRF-38534 CLASS H

MIL-PRF-38534 CLASS K

MSK5950KRHG

LEADS

GULL

WING

PART NUMBER

Rev. C 12/09