CS8311 Micropower 10 V, 100 mA Low Dropout Linear Regulator with RESET and ENABLE Features 10 V ±4.0% Output Low 100 µA Quiescent Current Active RESET ENABLE Input for ON/OFF and Active/Sleep Mode Control 100 mA Output Current Capability Fault Protection – +60 V Peak Transient Voltage – –15 V Reverse Voltage Short Circuit Thermal Overload • Low Reverse Current (Output to Input) • • • • • • Semiconductor Components Industries, LLC, 2001 April, 2001 – Rev. 5 1 http://onsemi.com SO–8 D SUFFIX CASE 751 8 1 PIN CONNECTIONS AND MARKING DIAGRAM VOUT VOUTSense ENABLE GND A WL, L YY, Y WW, W 1 8 8311 ALYWX The CS8311 is a precision 10 V micropower voltage regulator with very low quiescent current (100 µA typ at 100 µA load). The 10 V output is accurate within ±4.0% and supplies 100 mA of load current with a typical dropout voltage of only 400 mV. Microprocessor control logic includes an ENABLE input and an active RESET. The active RESET circuit includes hysteresis, and operates correctly at an output voltage as low as 1.0 V. The RESET function is activated during the power up sequence or during normal operation if the output voltage drops outside the regulation limits by more than 1.0 V typ. The logic level compatible ENABLE input allows the user to put the regulator into a shutdown mode where it draws only 20 µA typical of quiescent current. The regulator is protected against reverse battery, short circuit, over voltage, and thermal overload conditions. The device can withstand load dump transients making it suitable for use in automotive environments. VIN NC NC RESET = Assembly Location = Wafer Lot = Year = Work Week ORDERING INFORMATION Device Package Shipping CS8311YD8 SO–8 95 Units/Rail CS8311YDR8 SO–8 2500 Tape & Reel Publication Order Number: CS8311/D CS8311 VOUT VIN Current Source (Circuit Bias) Over Voltage Shutdown ENABLE Current Limit Sense VOUTSense + – Error Amplifier Thermal Protection Bandgap Reference RESET + – Reset Comparator GND Figure 1. Block Diagram ABSOLUTE MAXIMUM RATINGS* Rating Value Unit VIN 38 V Peak Transient Voltage (46 V Load Dump @ VIN = 14 V) 60 V –0.3 to +10.4 V 2.0 kV Junction Temperature Range –40 to +150 °C Storage Temperature Range –55 to +150 °C 230 peak °C ENABLE, RESET ESD Susceptibility (Human Body Model) Lead Temperature Soldering: Reflow (SMD styles only) (Note 1.) 1. 60 second maximum above 183°C. *The maximum package power dissipation must be observed. http://onsemi.com 2 CS8311 ELECTRICAL CHARACTERISTICS (11 V ≤ VIN ≤ 26 V; IOUT = 1.0 mA; –40 ≤ TA ≤ 125, –40°C ≤ TJ ≤ 150°C; unless otherwise specified.) Characteristic Test Conditions Min Typ Max Unit Output Voltage, VOUT 11 V < VIN < 26 V, 100 µA ≤ IOUT ≤ 100 mA 9.60 10.00 10.40 V Dropout Voltage (VIN – VOUT) IOUT = 100 mA IOUT = 100 µA – – 400 100 600 150 mV mV Load Regulation VIN = 14 V, 100 µA ≤ IOUT ≤ 100 mA – 5.0 100 mV Line Regulation 11 V < V < 26 V, IOUT = 1.0 mA – 5.0 100 mV Quiescent Current, (IQ) Active Mode IOUT = 100 µA IOUT = 50 mA IOUT = 100 mA – – – 100 4.0 12 250 6.0 20 µA mA mA Quiescent Current, (IQ) Sleep Mode VOUT = OFF, VIN = 12 V, VENABLE = 2.0 V – 20 50 µA Ripple Rejection 14 ≤ VIN ≤ 26 V, IOUT = 100 mA, f = 120 Hz 60 75 – dB – 105 200 – mA Output Stage Current Limit Short Circuit Output Current VOUT = 0 V 25 125 – mA Overvoltage Shutdown VOUT ≤ 1.0 V 30 34 38 V Reverse Current VOUT = 5.0 V, VIN = 0 V – 100 250 µA Threshold High (VOUT OFF) – 1.4 2.0 V Threshold Low (VOUT ON) 0.6 1.4 – V Input Current VENABLE = 2.4 V – 30 100 µA RESET Threshold High (VRH) VOUT Increasing 8.50 9.00 VOUT – 0.50 V RESET Threshold Low (VRL) VOUT Decreasing 8.30 8.90 VOUT – 0.45 V RESET Hysteresis (High – Low) 50 100 200 mV Reset Output Leakage RESET = High VOUT ≥ VRH – – 25 µA Output Voltage Low (VRLO) RRESET = 10 k, 1.0 V ≤ VOUT ≤ VRL – 0.1 0.4 V Output Voltage Low (VRPEAK) RRESET = 10 k, VOUT, Power up, Power down – 0.6 1.0 V ENABLE Input (ENABLE) Reset Function (RESET) PACKAGE LEAD DESCRIPTION PACKAGE LEAD # SO–8 LEAD SYMBOL 1 VOUT 2 VOUTSense 3 ENABLE 4 GND 5 RESET 6, 7 NC No connection. 8 VIN Input voltage. FUNCTION 10 V, ±4.0%, 100 mA output. Kelvin connection which allows remote sensing of output voltage for improved regulation. If remote sensing is not required, connect to VOUT. Logic level switches output off when toggled HIGH. Ground. All GND leads must be connected to Ground. Active reset (accurate to VOUT ≥ 1.0 V). http://onsemi.com 3 CS8311 CIRCUIT DESCRIPTION VOLTAGE REFERENCE AND OUTPUT CIRCUITRY ENABLE Function The ENABLE function switches the output transistor ON and OFF. When the voltage on the ENABLE lead exceeds 1.4 V typ, the output pass transistor turns off, leaving a high impedance facing the load. The IC will remain in Sleep mode, drawing only 50 µA (max), until the voltage on this input drops below the ENABLE threshold. Output Stage Protection The output stage is protected against overvoltage, short circuit and thermal runaway conditions (Figure 2). > 30 V VIN RESET Function A RESET signal (low voltage) is generated as the IC powers up until VOUT is within 1.0 V of the regulated output voltage, or when VOUT drops out of regulation, and is lower than 1.1 V below the regulated output voltage. A hysteresis of 50 mV is included in the function to minimize oscillations. The RESET output is an open collector NPN transistor, controlled by a low voltage detection circuit. The circuit is functionally independent of the rest of the IC thereby guaranteeing that the RESET signal is valid for VOUT as low as 1.0 V. VOUT IOUT Load Dump Current Limit Short Circuit Figure 2. Typical Circuit Waveforms for Output Stage Protection If the input voltage rises above 30 V (e.g. load dump), the output shuts down. This response protects the internal circuitry and enables the IC to survive unexpected voltage transients. Should the junction temperature of the power device exceed 180°C (typ) the load current capability is reduced thereby preventing thermal overload. This thermal management function is an effective means to prevent die overheating since the load current is the principle heat source in the IC. CS8311 Figure 4. RC Network for RESET Delay An external RC network on the lead (Figure 4) provides a sufficiently long delay for most microprocessor based applications. RC values can be chosen using the following formula: For 11 V < VIN < 26 V RTOTCRST VIN ENABLE RESET –tDelay V V lnV T VOUT RST OUT where: RRST = RESET Delay resistor RIN = µP port impedance RTOT = RRST in parallel with RIN CRST = RESET Delay capacitor tDelay = desired delay time VRST = VSAT of RESET lead (0.7 V @ turn – ON) VT = RESET threshold. VIN(H) VRH ON VRL OFF (1) (2) to µP RESET Port CRST The CS8311 contains two microprocessor compatible control functions: ENABLE and RESET (Figure 3). VRPEAK COUT RRST RESET REGULATOR CONTROL FUNCTIONS VOUT 5.0 V to µP and System Power VOUT VRPEAK VRLO (1) = No Reset Delay Capacitor (2) = With Reset Delay Capacitor Figure 3. Circuit Waveform http://onsemi.com 4 CS8311 APPLICATION NOTES 10 V, 100 mA VIN VBAT VOUT To Load 0.1 µF CS8311 500 kΩ ENABLE COUT RRST To µP RESET GND CRST To µP I/O Q1 100 kΩ 500 kΩ 100 kΩ SWITCH Figure 5. Microprocessor Control of CS8311 Using External Switching Transistor Q1 STABILITY CONSIDERATIONS The circuit depicted in Figure 5 lets the system control its power source, the CS8311 regulator. A SWITCH (potentially an I/O port on microprocessor) is used to drive the base of Q1. When Q1 is driven into saturation, the voltage on the ENABLE lead falls below its lower threshold. The regulator’s output is enabled. When the drive current is removed, the voltage on the ENABLE lead rises, the output is switched off and the IC moves into Sleep mode where it draws 50 µA (max). By coupling these two controls with the ENABLE lead, the system has added flexibility. Once the system is running, the state of the SWITCH is irrelevant as long as the I/O port continues to drive Q1. The microprocessor can turn off its own power by withdrawing drive current, once the SWITCH is open. This software control at the I/O port allows the microprocessor to finish key housekeeping functions before power is removed. The logic options are summarized in Table 1. The output or compensation capacitor helps determine three main characteristics of a linear regulator: start–up delay, load transient response and loop stability. VIN Switch ENABLE Output ON Closed LOW ON Open LOW ON OFF Closed LOW ON Open HIGH OFF CS8311 RRST COUT** 10 µF RESET ENABLE *CIN required if regulator is located far from the power supply filter. *COUT required for stability. Capacitor must operate at minimum temperature expected. Figure 6. Test and Application Circuit Showing Output Compensation The capacitor value and type should be based on cost, availability, size and temperature constraints. A tantalum or aluminum electrolytic capacitor is best, since a film or ceramic capacitor with almost zero ESR can cause instability. The aluminum electrolytic capacitor is the least expensive solution, but, if the circuit operates at low temperatures (–25°C to –40°C), both the value and ESR of the capacitor will vary considerably. The capacitor manufacturers data sheet usually provides this information. The value for the output capacitor COUT shown in Figure 6 should work for most applications, however it is not necessarily the optimized solution. Table 1. Logic Control of CS8311 Output Microprocessor I/O Drive VOUT CIN* 0.1 µF The I/O port of the microprocessor typically provides 50 µA to Q1. In automotive applications the SWITCH is connected to the ignition switch. http://onsemi.com 5 CS8311 To determine an acceptable value for COUT for a particular application, start with a tantalum capacitor of the recommended value and work towards a less expensive alternative part. Step 1: Place the completed circuit with a tantalum capacitor of the recommended value in an environmental chamber at the lowest specified operating temperature and monitor the outputs with an oscilloscope. A decade box connected in series with the capacitor will simulate the higher ESR of an aluminum capacitor. Leave the decade box outside the chamber, the small resistance added by the longer leads is negligible. Step 2: With the input voltage at its maximum value, increase the load current slowly from zero to full load while observing the output for any oscillations. If no oscillations are observed, the capacitor is large enough to ensure a stable design under steady state conditions. Step 3: Increase the ESR of the capacitor from zero using the decade box and vary the load current until oscillations appear. Record the values of load current and ESR that cause the greatest oscillation. This represents the worst case load conditions for the regulator at low temperature. Step 4: Maintain the worst case load conditions set in step 3 and vary the input voltage until the oscillations increase. This point represents the worst case input voltage conditions. Step 5: If the capacitor is adequate, repeat steps 3 and 4 with the next smaller valued capacitor. A smaller capacitor will usually cost less and occupy less board space. If the output oscillates within the range of expected operating conditions, repeat steps 3 and 4 with the next larger standard capacitor value. Step 6: Test the load transient response by switching in various loads at several frequencies to simulate its real working environment. Vary the ESR to reduce ringing. Step 7: Raise the temperature to the highest specified operating temperature. Vary the load current as instructed in step 5 to test for any oscillations. where: VIN(max) is the maximum input voltage, VOUT(min) is the minimum output voltage, IOUT(max) is the maximum output current for the application, and IQ is the quiescent current the regulator consumes at IOUT(max). Once the value of PD(max) is known, the maximum permissible value of RΘJA can be calculated: RJA (2) The value of RΘJA can then be compared with those in the package section of the data sheet. Those packages with RΘJA’s less than the calculated value in equation 2 will keep the die temperature below 150°C. In some cases, none of the packages will be sufficient to dissipate the heat generated by the IC, and an external heatsink will be required. IIN VIN IOUT SMART REGULATOR VOUT Control Features IQ Figure 7. Single Output Regulator With Key Performance Parameters Labeled HEAT SINKS A heat sink effectively increases the surface area of the package to improve the flow of heat away from the IC and into the surrounding air. Each material in the heat flow path between the IC and the outside environment will have a thermal resistance. Like series electrical resistances, these resistances are summed to determine the value of RΘJA. Once the minimum capacitor value with the maximum ESR is found, a safety factor should be added to allow for the tolerance of the capacitor and any variations in regulator performance. Most good quality aluminum electrolytic capacitors have a tolerance of ± 20% so the minimum value found should be increased by at least 50% to allow for this tolerance plus the variation which will occur at low temperatures. The ESR of the capacitor should be less than 50% of the maximum allowable ESR found in step 3 above. RJA RJC RCS RSA (3) where: RΘJC = the junction–to–case thermal resistance, RΘCS = the case–to–heatsink thermal resistance, and RΘSA = the heatsink–to–ambient thermal resistance. RΘJC appears in the package section of the data sheet. Like RΘJA, it too is a function of package type. RΘCS and RΘSA are functions of the package type, heatsink and the interface between them. These values appear in heat sink data sheets of heat sink manufacturers. CALCULATING POWER DISSIPATION IN A SINGLE OUTPUT LINEAR REGULATOR The maximum power dissipation for a single output regulator (Figure 7) is: PD(max) VIN(max) VOUT(min)IOUT(max) VIN(max)IQ 150°C TA PD (1) http://onsemi.com 6 CS8311 PACKAGE DIMENSIONS SO–8 D SUFFIX CASE 751–07 ISSUE W NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. –X– A 8 5 0.25 (0.010) S B 1 M Y M 4 K –Y– G C N X 45 SEATING PLANE –Z– 0.10 (0.004) H D 0.25 (0.010) M Z Y S X M J DIM A B C D G H J K M N S MILLIMETERS MIN MAX 4.80 5.00 3.80 4.00 1.35 1.75 0.33 0.51 1.27 BSC 0.10 0.25 0.19 0.25 0.40 1.27 0 8 0.25 0.50 5.80 6.20 S PACKAGE THERMAL DATA Parameter SO–8 Unit RΘJC Typical 45 °C/W RΘJA Typical 165 °C/W http://onsemi.com 7 INCHES MIN MAX 0.189 0.197 0.150 0.157 0.053 0.069 0.013 0.020 0.050 BSC 0.004 0.010 0.007 0.010 0.016 0.050 0 8 0.010 0.020 0.228 0.244 CS8311 SMART REGULATOR is a registered trademark of Semiconductor Components Industries, LLC (SCILLC). ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. 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