MIL-PRF-38534 CERTIFIED M.S.KENNEDY CORP. RAD HARD ULTRA LOW VOLTAGE ADJUSTABLE POSITIVE LINEAR REGULATOR 5950RH 4707 Dey Road Liverpool, N.Y. 13088 (315) 701-6751 FEATURES: 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 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. EQUIVALENT SCHEMATIC TYPICAL APPLICATIONS TYPICAL APPLICATIONS PIN-OUT INFORMATION Satellite System Power Supplies Switching Power Supply Post Regulators Constant Voltage/Current Regulators Microprocessor Power Supplies 1 2 3 4 5 6 7 8 9 10 1 VINA VINB VINC VIND VINE VBIAS GND1 GND1 Latch Shutdown 20 19 18 17 16 15 14 13 12 11 VOUTE VOUTD VOUTC VOUTB VOUTA VREF GND2 GND2 GND2 FB Rev. C 12/09 8 ABSOLUTE MAXIMUM RATINGS +VBIAS +VIN IVREF IOUT TC Bias Supply Voltage 10.0V Supply Voltage 10.0V Reference Sink Current 20mA Output Current 7 5A Case Operating Temperature Range MSK5950K/H/E RH -55C to +125C MSK5950RH -40C to +85C TST TLD PD TC Storage Temperature Range -65C to +150C Lead Temperature Range 300C (10 Seconds) Power Dissipation See SOA Curve Junction Temperature 150C ELECTRICAL SPECIFICATIONS NOTES: 1 2 3 4 5 6 Unless otherwise specified, VBIAS=VIN=3.3V, R1=61.9, RREF=249 (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=+25C Subgroup 2,5 TC=+125C Subgroup 3,6 TA=-55C 7 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. 8 Continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle. 9 Pre and post irradiation limits @25C, up to 300 Krad TID, are identical unless otherwise specified. 2 Rev. C 12/09 APPLICATION NOTES PIN FUNCTIONS 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 7.2A (nominal) current source. Exceeding the thermal 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. Momentarily 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 recharge 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 disabled and the current limit feature will force the output voltage to droop but remain active if excessive current is drawn. 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 stability. This reference voltage is used along with the feedback voltage to configure the desired output voltage. The reference will maintain good regulation as long as 0.4ISHUNT10mA. The shunt current is derived from a resistor tied to VIN or VBIAS. The resistor must supply both the minimum shunt current of 400A (1mA recommended) and the current required by the output voltage 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. 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. Resistor calculation example: VBIAS=3.3V10% VOUT=0.9V First determine the required current by selecting R2 in the feed back divider, typically between 1.0 and 1.2K; see the output voltage selection paragraph. Using standard value 0.1% tolerance resistors, the nominal output will be 0.9V with R2=1.07K and R1=316. The current in the divider will be equal to (VREFVFDBK)/R2 or 1.154mA nominal and 1.2mA worst-case in this example. FB - The FB 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 FB pin to 1.265V. An external resistor divider is connected to the output, FB pin, VREF and VIN to set the output voltage. The total current required is the sum of the worst-case divider current plus the VREF shunt current. The minimum shunt current is 400A but 1mA is recommended. Using the recommended 1mA the minimum current required in RREF is 2.2mA. POWER SUPPLY BYPASSING To maximize transient response and minimize power supply transients it is recommended that a 33F minimum tantalum capacitor is connected between VIN and ground. A 0.1F ceramic capacitor should also be used for high frequency bypassing. The maximum resistor value to source the required current is equal to (VBIAS min-VREF)/2.2mA or 218 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. OUTPUT CAPACITOR SELECTION 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 90 resistor will sink 10mA during operation and pull the output well below 200mV when the regulator is disabled in this application. Typically, large bulk capacitance is required at the output of a linear regulator to maintain good load transient response. However, with the MSK 5950RH this is not the case. A 47F surface mount tantalum capacitor in parallel with a 0.1F 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. 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. THERMAL LIMITING GND1 - Internally connected to input ground, these pins should be connected externally by the user to the circuit ground and the GND2 pins. The MSK 5950RH control circuitry has a thermal shutdown temperature of approximately 150C. 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 150C. Proper heat sink selection is essential 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. 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 Rev. C 12/09 APPLICATION NOTES CONT. HEAT SINK SELECTION 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 capacitor or pulsing the shutdown pin high. The shutdown pulse duration is partially dependent upon the size of the latch capacitor and should be characterized for each application; 30uS is typically adequate for a 1uF latch capacitor at 25C. 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 current curves). To select a heat sink for the MSK 5950RH, the following formula for convective heat flow may be used. Governing Equation: TJ = PD X (RJC + RCS + RSA) + TA Where TJ PD RJC RCS RSA 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 Power Dissipation=(VIN-VOUT) x IOUT Next, the user must select a maximum junction temperature. The absolute maximum allowable junction temperature is 150C. The equation may now be rearranged to solve for the required heat sink to ambient thermal resistance (RSA). 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 applications for automatic start up when VBIAS rises before VIN. Example: An MSK 5950RH is connected for VIN=+3.3V and VOUT=+1.2V. IOUT is a continuous 1A DC level. The ambient temperature is +25C. The maximum desired junction temperature is +125C. RJC=8.4C/W and RCS=0.15C/W for most thermal greases Power Dissipation=(3.3V-1.2V) x (1A) =2.1Watts Solve for RSA: RSA= 125C - 25C 2.1W -8.4C/W - 0.15C/W = 39C/W In this example, a heat sink with a thermal resistance of no more than 39C/W must be used to maintain a junction temperature of no more than 125C. 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. Reference 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 25C, the latch charging current is 7.2A at VBIAS=3V and 8A 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. 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 throughout 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. http://www.mskennedy.com/store.asp?pid=9951&catid=19680 4 Rev. C 12/09 APPLICATION NOTES CONT. TYPICAL APPLICATIONS CIRCUIT For output voltages above the feedback voltage the unit should be configured as shown in Figure 2. FIGURE 1 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 tolerance of 1.225V, R3 as shown in Figure 1 can be omitted. Output voltage can be calculated as follows: FIGURE 2 VOUT=1.265(1+R1/R2) Given: VFB=1.265V VREF=2.5V As noted in the above typical applications circuit, the formula for output voltage selection is: VOUT=VFB-((VREF-VFB)/R2)R1 VOUT=1.265(1+(R1/R2)) For convenience Table 1 below provides standard 0.1% tolerance resistor values required to achieve several output voltages based on nominal feedback voltage, R3 is ommitted. 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 combinations based on industry standard usage, R3 is ommitted. For output voltages close to the feedback voltage tolerance of 1.225V-1.305V, a three resistor network may be used to improve adjustment capabilities and trim out initial feedback voltage tolerances. Reference Figure 1. 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. VOUT= (R2R3VFB+R1R3(VFB-VREF)+R1R2VFB)/(R2R3) 5 Rev. C 12/09 TYPICAL PERFORMANCE CURVES 6 Rev. C 12/09 TYPICAL PERFORMANCE CURVES 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. 7 Rev. C 12/09 MECHANICAL SPECIFICATIONS WEIGHT=3.5 GRAMS TYPICAL NOTE: ALL DIMENSIONS ARE 0.010 INCHES UNLESS OTHERWISE LABELED. ESD Triangle indicates pin 1. ORDERING INFORMATION PART NUMBER SCREENING LEVEL MSK5950RH INDUSTRIAL MSK5950ERH EXTENDED RELIABILITY MSK5950HRH MIL-PRF-38534 CLASS H MSK5950KRH MIL-PRF-38534 CLASS K 8 LEADS STRAIGHT Rev. C 12/09 MECHANICAL SPECIFICATIONS CONTINUED WEIGHT=3.3 GRAMS TYPICAL ALL DIMENSIONS ARE 0.010 INCHES UNLESS OTHERWISE LABELED. ESD Triangle indicates pin 1. ORDERING INFORMATION PART NUMBER SCREENING LEVEL MSK5950RHG INDUSTRIAL MSK5950ERHG EXTENDED RELIABILITY MSK5950HRHG MIL-PRF-38534 CLASS H MSK5950KRHG 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. Contact MSK for MIL-PRF-38534 Class H, Class K status. 9 Rev. C 12/09