CS8391 CS8391 5V/250mA, 5V/100mA Micropower Low Dropout Regulator with ENABLE Description The CS8391 is a precision, dual 5V micropower linear voltage regulator. The switched primary output (VOUT1) supplies up to 250mA while the secondary (VOUT2) is capable of supplying 100mA. Both outputs have a maximum dropout voltage of 600mV and low reverse current. Quiescent current drain is typically 150µA when supplying 100µA from each output. The ENABLE input provides logic Features level control of the primary output. With the primary output disabled, quiescent current drain is typically 100µA when supplying 100µA from the secondary output. The CS8391 is extremely robust with protection provided for reverse battery, short circuit, and overtemperature on both outputs. The CS8391 is available in a 5-lead D2PAK. Absolute Maximum Ratings Input Voltage.....................................................................................-15V to 45V Power Dissipation .................................................................Internally Limited Operating Temperature Range................................................-40¡C to +125¡C Maximum Junction Temperature ...........................................-40¡C to +150¡C Storage Temperature Range ....................................................-55¡C to +150¡C Electrostatic Discharge (Human Body Model) ..........................................4kV Lead Temperature Soldering Wave Solder (through hole styles only)..........10 sec. max, 260¡C peak Reflow (SMD styles only)...........60 sec. max above 183¡C, 230¡C peak ■ 5V, 250mA Primary Output ■ 5V, 100mA Secondary Output ■ 3% Tolerance, Both Outputs ■ ON/OFF Control for Primary Output ■ Low Quiescent Current Drain (100µA VOUT2) ■ Low Reverse Current ■ Protection Features Reverse Battery (-15V) Short Circuit Overtemperature Package Options 5 Lead D2PAK Tab (Gnd) Block Diagram Primary Output VOUT1 VIN * Current Limit + ENABLE VOUT1Sense + Bandgap Reference *Note: Internally connected on 5 leaded package. Thermal Shutdown 1 1. VIN 2. VOUT1 3. Gnd 4. VOUT2 5. ENABLE Secondary Output VOUT2 * Current Limit VOUT2Sense + - Consult factory for 8L and 16L SO, 8L and 16L PDIP, 7L D2PAK and 5L TO-220. Gnd Cherry Semiconductor Corporation 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885-3600 Fax: (401)885-5786 Email: [email protected] Web Site: www.cherry-semi.com Rev. 1/12/98 1 A ¨ Company CS8391 Electrical Characteristics: 6V ² VIN ² 26V, IOUT1 = IOUT2 = 100µA, -40¡C ² TC ² 125ûC, -40¡C ² TJ ² 150ûC unless otherwise specified PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 4.85 5.00 400 100 5.15 600 150 V mV mV ■ Primary Output Stage (VOUT1) Output Voltage, VOUT1 Dropout Voltage 100µA ² IOUT1 ² 250mA IOUT1 = 250mA IOUT1 = 100µA Line Regulation 6V ² VIN ² 26V 5 50 mV Load Regulation 1mA ² IOUT1 ² 250mA, VIN = 14V 5 50 mV Quiescent Current ENABLE = HIGH, VIN = 16V, IOUT1 = 250mA f = 120Hz, IOUT1 = 125mA, 7V ² VIN ² 17V 22 50 mA Ripple Rejection Current Limit Short Circuit Current Limit VOUT1 = 0V, VIN = 16V Reverse Current VOUT1 = 5V, VIN = 0V 60 70 dB 260 400 mA 25 mA 100 1500 µA 5.00 5.15 V ■ Secondary Output (VOUT2) Output Voltage, VOUT2 100µA ² IOUT2 ² 100mA Dropout Voltage IOUT2 = 100mA IOUT2 = 100µA 400 100 600 150 mV mV Line Regulation 6V ² VIN ² 26V 5 50 mV Load Regulation 100µA ² IOUT2 ² 100mA, VIN = 14V 5 50 mV Quiescent Current ENABLE = LOW, VIN = 12.8V ENABLE = HIGH, VIN = 16V, IOUT2 = 100mA 100 8 150 25 µA mA Ripple Rejection f = 120Hz, IOUT2 = 50mA, 7V ² VIN ² 17V 4.85 Current Limit Short Circuit Current Limit VOUT2 = 0V, VIN = 16V, IOUT1 = 0A Reverse Current VOUT2 = 5V, VIN = 0V 60 70 dB 105 200 mA 25 mA 100 250 µA 0.8 V V µA ■ Enable Function (ENABLE) Input Threshold Input Bias Current ENABLE = LOW, 7V ² VIN ² 26V ENABLE = HIGH, 7V ² VIN ² 26V 0V ² VENABLE ² 5V 2.0 -2 1.2 1.2 0 (Guaranteed by Design) 150 180 2 ■ Protection Circuits Overtemperature Threshold 2 ¡C CS8391 Package Lead Description PACKAGE LEAD # LEAD SYMBOL FUNCTION 5 Lead D2PAK 1 2 VIN VOUT1 Supply voltage to IC, usually direct from battery. 5V regulated output which is activated by ENABLE input. 3 Gnd Ground connection. 4 VOUT2 Standby output 5V, 100mA capability; always on. 5 ENABLE CMOS compatible input lead; switches VOUT1. When ENABLE is high, VOUT1 is active. Definition of Terms Current Limit Peak current that can be delivered to the output. Load Regulation The change in output voltage for a change in load current at constant chip temperature. Dropout Voltage The input-output voltage differential at which the circuit ceases to regulate against further reduction in input voltage. Measured when the output voltage has dropped 100mV from the nominal value obtained at 14V input, dropout voltage is dependent upon load current and junction temperature. Long Term Stability Output voltage stability under accelerated life-test conditions after 1000 hours with maximum rated voltage and junction temperature. Quiescent Current The part of the positive input current that does not contribute to the positive load current. i.e., the regulator ground lead current. Input Output Differential The voltage difference between the unregulated input voltage and the regulated output voltage for which the regulator will operate. Ripple Rejection The ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage. Input Voltage The DC voltage applied to the input terminals with respect to ground. Short Circuit Current Limit Peak current that can be delivered by the output when forced to 0V. Line Regulation The change in output voltage for a change in the input voltage. The measurement is made under conditions of low dissipation or by using pulse techniques such that the average chip temperature is not significantly affected. Temperature Stability of VOUT The percentage change in output voltage for a thermal variation from room temperature to either temperature extreme. Typical Circuit Waveform 45V VIN 14V ENABLE 2.0V 0.8V 26V 31V 14V 3V 5V 5V 5V 5V 5V 5V 2.4V 0V 0V VOUT1 0V VOUT2 5V 5V 5V 5V 5V 5V 0V 5V 2.4V 0V System Condition Turn On Load Dump Low VIN Line Noise, Etc. 3 VOUT 1 Short Circuit VOUT2 Short Circuit Thermal Shutdown Turn Off CS8391 Application Notes IOUT2(max) is the maximum output current for the application, and General The CS8391 is a micropower dual 5V regulator. All bias required to operate the internal circuitry is derived from the standby output, VOUT2. If this output experiences an over current situation and collapses, then VOUT1 will also collapse (see timing diagrams). IQ is the quiescent current the regulator consumes at both IOUT1(max) and IOUT2(max). Once the value of PD(max) is known, the maximum permissible value of RQJA can be calculated: If there is critical circuitry that must remain active under most conditions it should be connected to VOUT2. Any circuitry that is likely to be subjected to a short circuit, e.g., circuitry outside the module, should be connected to VOUT1. 150¡C - TA (2) PD The value of RQJA can then be compared with those in the package section of the data sheet. Those packages with RQJA's less than the calculated value in equation 2 will keep the die temperature below 150¡C. RQJA = External Capacitors Output capacitors are required for stability with the CS8391. Without them, the regulator outputs will oscillate. Actual size and type may vary depending upon the application load and temperature range. Capacitor effective series resistance (ESR) is also a factor in the IC stability. Worstcase is determined at the minimum ambient temperature and maximum load expected. In some cases, none of the packages will be sufficient to dissipate the heat generated by the IC, and an external heat sink will be required. IIN Smart Regulator VIN Output capacitors can be increased in size to any desired value above the minimum. One possible purpose of this would be to maintain the output voltages during brief conditions of negative input transients that might be characteristic of a particular system. IOUT1 VOUT1 IOUT2 VOUT2 } Capacitors must also be rated at all ambient temperatures expected in the system. To maintain regulator stability down to -40ûC, capacitors rated at that temperature must be used. Control Features IQ More information on capacitor selection for Smart Regulatorsª is available in the Smart Regulator application note, Compensation for Linear Regulators. Figure 1: Dual 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. ENABLE The ENABLE function controls VOUT1. When ENABLE is high, VOUT1 is on. When ENABLE is low, VOUT1 is off. 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 RQJA: Calculating Power Dissipation in a Dual Output Linear Regulator RQJA = RQJC + RQCS + RQSA The maximum power dissipation for a dual output regulator (Figure 1) is: (3) where: RQJC = the junctionÐtoÐcase thermal resistance, PD(max) = {VIN(max)ÐVOUT1(min)}IOUT1(max)+ {VIN(max)ÐVOUT2(min)}IOUT2(max)+VIN(max)IQ (1) RQCS = the caseÐtoÐheat sink thermal resistance, and RQSA = the heat sinkÐtoÐambient thermal resistance. where: VIN(max) is the maximum input voltage, RQJC appears in the package section of the data sheet. Like RQJA, it too is a function of package type. RQCS and RQSA are functions of the package type, heat sink and the interface between them. These values appear in heat sink data sheets of heat sink manufacturers. VOUT1(min) is the minimum output voltage from VOUT1, VOUT2(min) is the minimum output voltage from VOUT2, IOUT1(max) is the maximum output current for the application, 4 CS8391 Test & Application Circuit VIN 0.1mF C1 VBATT VOUT2 CS8391 VCC C2 22mF ESR<8W mP VOUT1 22mF ESR<8W Load C3 ENABLE I/O Gnd Gnd * C1 required if regulator is located far from power supply filter. ** C2 and C3 required for stability. Capacitor must operate at minimum temperature expected during system operations. 5 CS8391 Package Specification PACKAGE DIMENSIONS IN MM(INCHES) PACKAGE THERMAL DATA Thermal Data 5 Lead D2 PAK RQJC typ 2.4 ¡C/W RQJA typ 10-50* ¡C/W * Depending on thermal properties of substrate. RQJA = RQJC + RQCA 5 Lead D2PAK (DP) 10.31 (.406) 10.05 (.396) 1.40 (.055) 1.14 (.045) 1.68 (.066) 1.40 (.055) 8.53 (.336) 8.28 (.326) 15.75 (.620) 14.73 (.580) 2.74(.108) 2.49(.098) 0.91 (.036) 0.66 (.026) 2.79 (.110) 2.29 (.090) 1.70 (.067) REF 4.57 (.180) 4.31 (.170) .254 (.010) REF 0.10 (.004) 0.00 (.000) Ordering Information Part Number CS8391YDP5 CS8391YDPR5 Rev. 1/12/98 Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. Description 5 Lead D2PAK 5 Lead D2PAK (tape & reel) 6 © 1999 Cherry Semiconductor Corporation