RC4190 RAYTHEON | Alldatasheet
Document overview
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Technical content
Features
- High efficiency – 85% typical
- Low quiescent current – 215 m A
- Adjustable output – 1.3V to 30V
- High switch current – 200 mA
- Bandgap reference – 1.31V
Description
The RC4190 monolithic IC is a low power switch mode reg- ulator intended for miniature power supply applications. This DC-to-DC converter IC provides all of the active com- ponents needed to create supplies for micropower circuits (load power up to 400 mW, or up to 10W with an external power transistor). Contained internally are an oscillator, switch, reference, comparator, and logic, plus a discharged battery detection circuit. Application areas include on-card circuits where a non-standard voltage supply is needed, or in battery operated instruments where an RC4190 can be used to extend battery lifetime. These regulators can achieve up to 85% efficiency in most applications while operating over a wide supply voltage range, 2.2V to 30V , at a very low quiescent current drain of 215 m The standard application circuit requires just seven external components for step-up operation: an inductor, a steering diode, three resistors, a low value timing capacitor, and an electrolytic filter capacitor. The combination of simple appli- cation circuit, low supply current, and small package make the RC4190 adaptable to a wide range of miniature power supply applications. The RC4190 is most suited for single ended step-up OUT > V IN ) circuits because the NPN internal switch tran- sistor is referenced to ground. It is complemented by another Raytheon micropower switching regulator, the RC4391, which is dedicated to step-down (V OUT < V IN ) and inverting V OUT = –V IN ) applications. Between the two devices the ability to create all three basic switching regulator configura- tions is assured. Refer to the RC4391 data sheet for step- down and inverting applications. With some optional external components the application circuit can be designed to signal a display when the battery has decayed below a predetermined level, or designed to signal a display at one level and then shut itself off after the battery decays to a second level. See the applications section for these and other unique circuits. The RC4190 micropower switching regulator series consists of three devices, each with slightly different specifications. The RM4190 has a 1.5% maximum output voltage tolerance, 0.2% maximum line regulation, and operation to 30V . The RC4190 has a 5.0% maximum output voltage tolerance, 0.5% maximum line regulation, and operation to 24V . Other specifications are identical. Each type is available in plastic and ceramic DIPs, or SO-8 packages.
- Accurate oscillator frequency – 10%
- Remote shutdown capability
- Low battery detection circuitry
- Low component count
- 8-lead packages including small outline (SO-8) Block Diagram 1.31V REF OSC BIAS LBR VFB +V S IC LX C X Gnd 4190 +1.2V LBD 65-3464-01 +1.31V RC4190 Micropower Switching Regulator Rev. 1.0.0
PRODUCT SPECIFICATION RC4190 Absolute Maximum Ratings (beyond which the device may be damaged)1 Note: 1. Functional operation under any of these conditions is NOT implied. Operating Conditions Parameter Min Typ Max Units Supply Voltage (Without External Transistor) RM4190 30 V RC4190 24 V P D T A < 50 C SOIC 300 mW PDIP 468 mW CerDIP 833 mW Operating Temperature RM4190 -55 125 C RC4190 0 70 C Storage Temperature -65 150 C Junction Temperature SOIC, PDIP 125 C CerDIP 175 C Switch Current Peak 375 mA For T A > 50 C Derate at SOIC 4.17 mW/ C PDIP 6.25 mW/ C CerDIP 8.33 mW/ C Parameter Min Typ Max Units q JC Thermal resistance CerDIP 45 C/W q JA Thermal resistance SOIC 200 C/W PDIP 160 C/W CerDIP 120 C/W Pin Assignments LBR C X GND LX LBD V FB IC +V S 65-3464-02 Pin Definitions Pin Name Pin Number Pin Function Description LBR 1 Low Battery (Set) Resistor C X
2 Timing Capacitor
L X
4 External Inductor
S
5 Positive Supply Voltage
I C
6 Reference Set Current
V FB
7 Feedback Voltage
LBD 8 Low Battery Detector Output
RC4190 PRODUCT SPECIFICATION
Electrical Characteristics
(+V S = +6.0V, I C = 5.0 m A over the full operating temperature range unless otherwise noted.) Symbol Parameters Conditions RM4190 RC4190 UnitsMin Typ Max Min Typ Max S Supply Voltage 2.6 30 2.6 24 V V REF Reference Voltage (Internal) I SY Supply Current Measure at Pin 5 I = 0 235 350 235 350 m A Line Regulation 0.5 V OUT < V S V OUT O L I Load Regulation V S = 0.5 V OUT P L = 150 mW O I C Reference Set Current 1.0 5.0 50 1.0 5.0 50 m A I CO Switch Leakage CurrentV = 24V (RC4190) 30V (RM4190) 30 30 m A I SO Supply Current (Disabled) V C 200 mV 30 30 m A I LBD Low Battery Output Current V = 0.4V, V = 1.1V 500 1200 500 1200 m A Oscillator Frequency Temperature Drift 200 200 ppm/ C
PRODUCT SPECIFICATION RC4190 (+V S = +6.0V, I C = 5.0 m A, and T A = +25 C unless otherwise noted.) RM4190 RC4190 Symbol Parameters Conditions Min Typ Max Min Typ Max Units S Supply Voltage 2.2 30 2.2 24 V V REF Reference Voltage (Internal) I SW Switch Current V = 400 mV 100 200 100 200 mA I SY Supply Current Measure at Pin 5 I = 0 215 300 215 300 m A ef Efficiency 85 85 % Line Regulation 0.5 V OUT < V S V OUT 0.04 0.2 0.04 0.5 % V O L I Load Regulation V S = +0.5 V OUT P L = 150 mW O F O Operating Frequency Range 0.1 25 75 0.1 25 75 kHz I C Reference Set Current 1.0 5.0 50 1.0 5.0 50 m A I CO Switch Leakage Current V4 = 24V (RC4190) 30V (RM4190, RC4190A) 0.01 5.0 0.01 5.0 mA I SO Supply Current (Disabled) VC £ 200 mV 0.1 5.0 0.1 5.0 mA I1 Low Battery Bias Current V1 = 1.2V 0.7 0.7 mA ICX Capacitor Charging Current 8.6 8.6 mA Oscillator Frequency Tolerance –10 –10 % +V THX Capacitor Threshold Voltage + 1.4 1.4 V -VTHX Capacitor Threshold Voltage – 0.5 0.5 V IFB Feedback Input Current V7 = 1.3V 0.1 0.1 mA ILBD Low Battery Output Current V8 = 0.4V, V1 = 1.1V 500 1500 500 1500 mA
Figure 12. Step-Down Regulator Greater Than 30V nominal oscillator frequency. tions for ripple are at +VS (max). value is between 50 mA and 100 mA).
- Select an operating frequency and timing capacitor as
shown above (10 kHz to 40kHz is typical).
- Find the maximum on time (add 5 mS for the turn-off
- Calculate the peak inductor current IMAX (if this value
PRODUCT SPECIFICATION RC4190 4. Find an inductance value for LX : 5. The inductor chosen must exhibit approximately this value at a current level equal to IMAX . 6. Calculate a value for the output filter capacitor: where V R = ripple voltage (peak) Step-Down Design Procedure 1. Select an operating frequency. 2. Determine the maximum on time (TON ) as in the step- up design procedure. 3. Calculate IMAX : 4. Calculate LX : 5. Calculate a value for the output filter capacitor: Alternate Design Procedure The design equations above will not work for the certain input/output voltage ratios, and for these circuits another method of defining component values must be used. If the slope of the current discharge waveform is much less than the slope of the current charging waveform, then the inductor current will become continuous (never discharging com- pletely), and the equations will become extremely complex. So, if the voltage applied across the inductor during the charge time is greater than during the discharge time, used the design procedure below . For example, a step-down circuit with 20V input and 5V output will have approxi- mately 15V across the inductor when charging, and approxi- mately 5V when discharging. So in this example, the inductor current will be continuous and the alternate procedure will be necessary. 1. Select an operating frequency (a value between 10 kHz and 40 kHz is typical). 2. Build the circuit and apply the worst case conditions to it, i.e., the lowest battery voltage and the highest load current at the desired output voltage. 3. Adjust the inductor value down until the desired output voltage is achieved, then go a little lower (approxi- mately 20%) to cover manufacturing tolerances. 4. Check the output voltage with an oscilloscope for ripply, at high supply voltages, at voltages as high as are expected. Also check for efficiency by monitoring sup- ply and output voltages and currents [eff = (V OUT ) (IOUT )/(+VS)(ISY ) x 100%$]. 5. If the efficiency is poor, go back to (1) and start over. If the ripple is excessive, then increase the output filter capacitor value or start over. Compensation When large values (>50 kW ) are used for the voltage setting resistors, R2 and R3 of Figure 7, stray capacitance at the V FB input can add a lag to the feedback response, destabiliz- ing the regulator, increasing low frequency ripple, and lower- ing efficiency. This can often be avoided by minimizing the stray capacitance at the V FB node. It can also be remedied by adding a lead compensation capacitor of 100 pF to 10 nF in parallel with R2 in Figure 7. Inductors Efficiency and load regulation will improve if a quality high Q inductor is used. A ferrite pot core is recommended; the wind-yourself type with an air gap adjustable by washers or spacers is very useful for breadboarding prototypes. Care must be taken to choose a permeable enough core to handle the magnetic flux produced at IMAX ; if the core saturates, then efficiency and output current capability are severely degraded and excessive current will flow though the switch transistor. A pot core inductor design section is provided later in this datasheet. An isolated A C current probe for an oscilloscope (example: Tektronix P6042) is an excellent tool for saturation prob- lems; with it the inductor current can be monitored for non- linearity at the peaks (a sign of saturation). Low Battery Detector An open collector signal transistor Q2 with comparator C2 provides the designer with a method of signaling a display or computer whenever the battery voltage falls below a pro- grammed level (see Figure 8). This level is determined by the +1.3V reference level and by the selection of two external resistors according to the equation: Where V TH = Threshold Voltage for Detection L X H enries( ) V S V S W– IM A X æ öT O N= C F m F( ) T O N V S IM A X V O U T æ ö V R IM A X 2IL FO( ) T O N( ) V S V O U T– æ ö 1+ L X V S V O U T– IM A X æ ö T O N( )= C F m F( ) T O N V S V O U T–( )IM A X V O U T æ ö V R V T H V R E F R 4 æ ö=
Figure 15. Battery Back-Up Circuit Figure 16. 9.0V Battery Life Extender Figure 17. Bootstrapped Operation (Step-Up)
4190 V FB
910 R5*
Where C is in pF and FO is in Hz.
- Choose resistor values so R5 = R3 and R4 = R2, and make
- The inductor and capacitor values were chosen to achieve
in temperature and line voltage. Figure 21. Step-Down Regulator with Protection
PRODUCT SPECIFICATION RC4190 Simplified Schematic Diagram 65-2665 +VS (5) Q3 Q4 IC (6) 81.5K 34.4K 147K 3.5K 14.2pF Q5 Q6 Q10 23K 29.4pF Q13 Q17 Q15 Q14 Q11 Q12 Q16 131K (8) LBD Q24 Q23 Q22 Q21 Q25 Q26 Q19 Q20 Q18 Q27 Q50 Q28 Q29 LX (4) VFB (7) Q30 Q36 Q31 Q32 Q34 Q33 Q35 (1) LBR (3) Gnd Q37 C X (2) Q38 Q48 Q49 Q42 Q43 Q44 Q41 24K Q39 Q40 Q45 Q46 Q47 R10 80K 70K
PRODUCT SPECIFICATION RC4190 Troub leshooting Chart Symptom Possible Problem Draws excessive supply current on start-up Battery not "stiff" — inadequate supply bypass capacitor. Inductance value too low. Operating frequency (F O ) too low. Output voltage is low. Inductance value too high for FO or core saturating. Inductor "sings" with audible hum. Not potted well or bolted loosely. LX in appears noisy — scope will not synchronize.Normal operating condition. Inductor current shows nonlinear waveform. Inductor is saturating: 1. Core too small. 2. Core too hot. 3. Operating frequency too low. Inductor current shows nonlinear waveform. Waveform has resistive component: 1. Wire size too small. 2. Power transistor lacks base drive. 3. Components not rated high enough. 4. Battery has high series resistance. Inductor current is linear until high current is reached. External transistor lacks base drive or beta is too low. Poor efficiency. Core saturating. Diode or transistor: 1. Not fast enough. 2. Not rated for current level (high V CE SAT). High series resistance. Operating frequency too high. Motorboating (erratic current pulses). Loop stability problem — needs feedback capacitor from V OUT to VFB (pin 7), 100 to 1000 pF. 65-3464-04 ILX -IMAX Time 65-3464-05 ILX -IMAX Time 65-3464-06 ILX -IMAX Time
destructive inductor current.
- They are available in a wide range of sizes. RC4190
pot core can be chosen to meet the circuit requirements.
- Pot cores are easily mounted. They can be bolted
directly to the PC card adjacent to the regulator IC.
- Pot cores can be easily air-gapped. The length of the
- Electromagnetic interference (EMI) is kept to a
millimeter sizes including the sizes shown.
- From the application requirement, determine the induc-
tor value (L) and the required peak current (IMAX ).
- Observe the curves of the design aid graph and deter-
Figure 27. Inductor Design Aid
24 Gauge
70 Turns
26 Gauge
28 Gauge
60 Turns
30 Gauge
50 Turns
- Note the approximate air gap at IMAX for the selected
- If the required inductance is equal to the indicated value
easily wound in the cores winding area.
- If the required inductance is less than the value indicated
index) for a specific air gap.
- W ind and gap the core as per calculations, and measure
inductor lead and monitor the current in the inductor.
- After the operation in circuit has been checked,
recommended by the manufacturer. for any core geometry, such as an E-E core.
5083 Kings Highway
186 W ood A venue South
201 Stackpole Street
Figure 28. Inductor Current Waveforms
PRODUCT SPECIFICATION RC4190 Mec hanical DImensions 8-Lead Ceramic DIP Package 5 8 A — .200 — 5.08 Symbol Inches Min. Max. Min. Max. Millimeters Notes b1 .014 .023 .36 .58 .065 1.65b2 .045 1.14 c1 .008 .015 .20 .38 E .220 .310 5.59 7.87 e .100 BSC 2.54 BSC L .125 .200 3.18 5.08 .015 .060 .38 1.52 .005 — .13 — 2, 8 5, 9 eA .300 BSC 7.62 BSC 7 Q 90° 105° 90° 105°α D — .405 — 10.29 Notes: Index area: a notch or a pin one identification mark shall be located adjacent to pin one. The manufacturer's identification shall not be used as pin one identification mark. The minimum limit for dimension "b2" may be .023 (.58mm) for leads number 1, 4, 5 and 8 only. Dimension "Q" shall be measured from the seating plane to the base plane. This dimension allows for off-center lid, meniscus and glass overrun. The basic pin spacing is .100 (2.54mm) between centerlines. Each pin centerline shall be located within –.010 (.25mm) of its exact longitudinal position relative to pins 1 and 8. Applies to all four corners (leads number 1, 4, 5, and 8). "eA" shall be measured at the center of the lead bends or at the centerline of the leads when "α " is 90°. All leads – Increase maximum limit by .003 (.08mm) measured at the center of the flat, when lead finish applied. Six spaces. Note 1 D E Q A e L eA c1α
RC4190 PRODUCT SPECIFICATION Mec hanical DImensions (continued) 8-Lead Plastic DIP Package A — .210 — 5.33 Symbol Inches Min. Max. Min. Max. Millimeters Notes A1 .015 — .38 — .022 .56B .014 .36 B1 .045 .070 1.14 1.78 D .348 .430 8.84 10.92 .300 .325 7.62 8.26 .240 .280 6.10 7.11 E e — .430 — 10.92 .005 — .13 — A2 .115 .195 2.93 4.95 .100 BSC 2.54 BSC eB .115 .160 2.92 4.06L 8° 8° 5N C .008 .015 .20 .38 Notes: Dimensioning and tolerancing per ANSI Y14.5M-1982. "D" and "E1" do not include mold flashing. Mold flash or protrusions shall not exceed .010 inch (0.25mm). Terminal numbers are for reference only. "C" dimension does not include solder finish thickness. Symbol "N" is the maximum number of terminals. D e B A L 5 8 E eB C
PRODUCT SPECIFICATION RC4190 Mec hanical DImensions (continued) 8-Lead SOIC Package 8 5 1 4 D A – C – ccc C LEAD COPLANARITY SEATING PLANEe B L h x 45° C α E H A .053 .069 1.35 1.75 Symbol Inches Min. Max. Min. Max. Millimeters Notes A1 .004 .010 0.10 0.25 .020 0.51B .013 0.33 C .008 .010 0.20 0.25 E .150 .158 3.81 4.01 e .228 .244 5.79 6.20 .010 .020 0.25 0.50 H .050 BSC 1.27 BSC h L .016 .050 0.40 1.27 0° 8° 0° 8° N 8 8 α ccc .004 0.10— — D .189 .197 4.80 5.00 Notes: Dimensioning and tolerancing per ANSI Y14.5M-1982. "D" and "E" do not include mold flash. Mold flash or protrusions shall not exceed .010 inch (0.25mm). "L" is the length of terminal for soldering to a substrate. Terminal numbers are shown for reference only. "C" dimension does not include solder finish thickness. Symbol "N" is the maximum number of terminals.
PRODUCT SPECIFICATION RC4190 12/95 0.0m Stock#DS20004190 © Raytheon Company The information contained in this data sheet has been carefully compiled; howe ver, it shall not by implication or otherwise become part of the terms and conditions of any subsequent sale. Raytheon’s liability shall be determined solely by its standard terms and conditions of sale. No representation as to application or use or that the circuits are either licensed or free from patent infringement is intended or implied. Raytheon reserves the right to change the circuitry and any other data at any time without notice and assumes no liability for errors. LIFE SUPPORT POLICY: Raytheon’s products are not designed for use in life support applications, wherein a failure or malfunction of the component can reasonably be expected to result in personal injury. The user of Raytheon components in life support applications assumes all risk of such use and indemnifies Raytheon Company against all damages. Raytheon Electronics Semiconductor Division
350 Ellis Street
650.968.9211 FAX 650.966.7742
Ordering Information
Note: 1. /883B suffix denotes MIL-STD-883, Level B processing. Product Number Temperature Range Screening Package RC4190M 0° to 70°C Commercial 8 Pin Narrow SOIC RC4190N 0° to 70°C Commercial 8 Pin Plastic DIP RM4190D -55°C to +125°C 8 Pin Ceramic DIP RM4190D/883B -55°C to +125°C Military 8 Pin Ceramic DIP RV4190N -25°C to +85°C Industrial 8 Pin Plastic DIP