CS5205-1,-3,-5 CS5205-1,-3,-5 5A Adjustable, and 3.3V and 5V Fixed Linear Regulators Description The CS5205-X series of linear regulators provides 5A at adjustable and fixed voltages with an accuracy of ±1% and ±2% respectively. The adjustable version uses two external resistors to set the output voltage within a 1.25V to 13V range. Features The circuit is designed to operate with dropout voltages as low as 1V depending on the output current level. The maximum quiescent current is only 10mA at full load. The regulators are fully protected against overload conditions with protection circuitry for Safe Operating Area (SOA), overcurrent and thermal shutdown. The regulators are intended for use as post regulators and microprocessor supplies. The fast loop response and low dropout voltage make these regulators ideal for applications where low voltage operation and good transient response are important. The CS5205-X is pin compatible with the LT1084 family of linear regulators but has lower dropout voltage. ■ Output Current to 5A ■ Output Trimmed to +/- 1% ■ Dropout Voltage 1.2V @ 5A ■ Fast Transient Response ■ Fault Protection Circuitry Thermal Shutdown Overcurrent Protection Safe Area Protection The regulators are available in TO220 and surface mount D2 packages. Block Diagram Package Options CS5205-1 V OUT V IN 3L D2PAK 3L TO-220 Tab (VOUT) Output Current Limit Thermal Shutdown - + Error Amplifier 1 Bandgap Adj CS5205-3, -5 V OUT 1 V IN Output Current Limit Thermal Shutdown - + 1 2 3 Error Amplifier CS5205-1 Adj VOUT VIN 1 2 3 CS5205-3, -5 Gnd VOUT VIN Bandgap 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. 6/12/97 1 A ¨ Company CS5205-1,-3,-5 Absolute Maximum Ratings Supply Voltage, VCC ..................................................................................................................................................................17V Operating Temperature Range................................................................................................................................-40¡C to 70¡C Junction Temperature ............................................................................................................................................................150¡C Storage Temperature Range ..................................................................................................................................-60¡C to 150¡C 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 Electrical Characteristics: CIN = 10µF, COUT = 22µF Tantalum, VIN Ð VOUT=3V, VIN ² 15V, 0¡C ² TA ² 70¡C, TJ ² +150¡C, unless otherwise specified, Ifull load = 5A. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 1.241 (-1%) 1.254 1.266 (+1%) V ■ Adjustable Output Voltage (CS5205-1) Reference Voltage (Notes 1 and 2) VINÐVOUT=1.5V; VAdj = 0V 10mA²IOUT²5A Line Regulation 1.5V²VINÐVOUT²6V; IOUT=10mA 0.04 0.20 % Load Regulation (Notes 1 and 2) VINÐVOUT=1.5V; 10mA²IOUT²5A 0.08 0.4 % Dropout Voltage (Note 3) IOUT=5A 1.2 1.3 V Current Limit VINÐVOUT=3V; TJ ³ 25¡C VINÐVOUT=9V Minimum Load Current VINÐVOUT=7V Adjust Pin Current Adjust Pin Current Change 5.5 1.5V²VINÐVOUT²4V; 10mA²IOUT²5A 8.5 1.0 A A 1.2 6 mA 50 0.2 100 5.0 µA µA Thermal Regulation 30ms pulse; TA=25¡C 0.003 %W Ripple Rejection f=120Hz; CAdj=25µF; IOUT=5A 82 dB 0.5 % 0.003 %VOUT 180 ¡C 25 ¡C Temperature Stability RMS Output Noise 10Hz²f²10kHz; TA=25¡C Thermal Shutdown 150 Thermal Shutdown Hysteresis Electrical Characteristics: CIN = 10µF, COUT = 22µF Tantalum, VIN Ð VOUT=3V, VIN ² 10V, 0¡C ² TA ² 70¡C, TJ ² +150¡C, unless otherwise specified, Ifull load = 5A. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ■ Fixed Output Voltage (CS5205-3, -5) CS5205-5 (Notes 1 and 2) VINÐVOUT=1.5V; 0²IOU T²5A 4.9 (-2%) 5.0 5.1 (+2%) V CS5205-3 (Notes 1 and 2) VINÐVOUT=1.5V; 0²IOUT²5A 3.234 (-2%) 3.300 3.366 (+2%) V Line Regulation 1.5V²VINÐVOUT ² 6V; IOUT=10mA 0.04 0.20 % Load Regulation (Notes 1 and 2) VINÐVOUT =1.5V; 10mA ² IOUT²5A 0.08 0.40 % Dropout Voltage (Note 3) IOUT=5A 1.2 1.3 V Current Limit VINÐVOUT=3V; TJ ³ 25¡C VINÐVOUT=9V 5.5 8.5 1.0 A A Quiescent Current VIN²9V; IOUT = 10mA 5.0 Thermal Regulation 30ms pulse; TA=25¡C 0.003 %/W Ripple Rejection f=120Hz; IOUT=5A 75 dB 0.5 % Temperature Stability 2 10.0 mA unless otherwise specified, Ifull load = 5A. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ■ Fixed Output Voltage (CS5205-3, -5): continued RMS Output Noise (%VOUT) 10Hz²f²10kHz Thermal Shutdown 150 Thermal Shutdown Hysteresis 0.003 %VOUT 180 ¡C 25 ¡C Note 1: Load regulation and output voltage are measured at a constant junction temperature by low duty cycle pulse testing. Changes in output voltage due to thermal gradients or temperature changes must be taken into account separately. Note 2: Specifications apply for an external Kelvin sense connection at a point on the output pin 1/4Ó from the bottom of the package. Note 3: Dropout voltage is a measurement of the minimum input/output differential at full load. Package Pin Description PACKAGE PIN # CS5205 -1 3L TO-220 D2PAK 1 1 2 2 3 3 N/A N/A PIN SYMBOL CS5205 -3, -5 D2PAK 3L TO-220 N/A N/A 2 2 3 3 1 1 FUNCTION Adj VOUT VIN Gnd Adjust pin (low side of the internal reference). Regulated output voltage (case). Input voltage. Ground connection. Typical Performance Characteristics 0.10 1.25 0.08 Dropout Voltage (V) 1.20 Output Voltage Deviation (%) 1.30 TCASE = 0°C 1.15 1.10 1.05 1.00 0.95 TCASE = 125°C 0.90 0.85 TCASE = 25°C 0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06 0.80 -0.08 0.75 -0.10 -0.12 0.70 0 1 2 3 Output Current (A) 4 0 5 10 20 30 40 50 60 70 80 90 100 110 120 130 TJ (°C) Dropout Voltage vs. Output Current Reference Voltage vs. Temperature 2.500 0.200 Minimum Load Current (mA) Output Voltage Deviation (%) 0.175 0.150 0.125 0.100 TCASE = 25°C 0.075 TCASE = 125°C 0.050 2.175 1.850 TCASE = 0°C 1.525 1.200 TCASE = 125°C 0.875 0.025 TCASE = 25°C TCASE = 0°C 0.550 0.000 0 1 2 3 4 1 5 2 Output Current (A) Load Regulation vs. Output Current Minimum Load Current 3 3 4 5 VIN – VOUT (V) 6 7 8 9 CS5205-1,-3,-5 Electrical Characteristics: CIN = 10µF, COUT = 22µF Tantalum, VIN Ð VOUT=3V, VIN ² 10V, 0¡C ² TA ² 70¡C, TJ ² +150¡C, CS5205-1,-3,-5 Typical Performance Characteristics: continued 100.0 70.0 90.0 IO = 10mA Ripple Rejection (dB) Adjust Pin Current (mA) 65.0 60.0 55.0 50.0 80.0 70.0 60.0 50.0 TCASE = 25°C IOUT = 5A (VIN Ð VOUT) = 3V VRIPPLE = 1.6VPP 40.0 30.0 20.0 45.0 10.0 0.0 40.0 0 10 20 30 40 50 60 70 80 101 90 100 110 120 130 102 103 Temperature (°C) 104 105 Frequency (Hz) Adjust Pin Current vs. Temperature Ripple Rejection vs. Frequency (Fixed Versions) 100.0 Ripple Rejection (dB) 90.0 80.0 70.0 60.0 50.0 TCASE = 25°C IOUT = 5A (VIN Ð VOUT) = 3V VRIPPLE = 1.6VPP CAdj = 25mF 40.0 30.0 20.0 10.0 0.0 101 102 103 104 105 Frequency (Hz) Ripple Rejection vs. Frequency (Adjustable Version) Applications Information The CS5205-X family of linear regulators provide fixed or adjustable voltages at currents up to 5A. The regulators are protected against short circuit, and include thermal shutdown and safe area protection (SOA) circuitry. The SOA protection circuitry decreases the maximum available output current as the input-output differential voltage increases. The CS5205-X has a composite PNP-NPN output transistor and requires an output capacitor for stability. A detailed procedure for selecting this capacitor is included in the Stability Considerations section. The output voltage is set according to the formula: ( ) VOUT = VREF ´ R1 + R2 + IAdj ´ R2 R1 The term IAdj ´ R2 represents the error added by the adjust pin current. R1 is chosen so that the minimum load current is at least 10mA. R1 and R2 should be the same type, e.g. metal film for best tracking over temperature. The adjust pin is bypassed to improve the transient response and ripple rejection of the regulator. Adjustable Operation The adjustable regulator (CS5205-1) has an output voltage range of 1.25V to 13V. An external resistor divider sets the output voltage as shown in Figure 1. The regulator maintains a fixed 1.25V (typical) reference between the output pin and the adjust pin. A resistor divider network R1 and R2 causes a fixed current to flow to ground. This current creates a voltage across R2 that adds to the 1.25V across R1 and sets the overall output voltage. The adjust pin current (typically 50µA) also flows through R2 and adds a small error that should be taken into account if precise adjustment of VOUT is necessary. VIN VOUT VIN C1 CS5205-1 VOUT VREF R1 C2 Adj IAdj CAdj R2 Figure 1. Resistor divider scheme for the adjustable version. 4 Stability Considerations IN4002 The output or compensation capacitor helps determine three main characteristics of a linear regulator: start-up delay, load transient response and loop stability. The capacitor value and type is 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. However, when the circuit operates at low temperatures, both the value and ESR of the capacitor will vary considerably. The capacitor manufacturers data sheet provides this information. A 22µF tantalum capacitor will work for most applications, but with high current regulators such as the CS5205-X the transient response and stability improve with higher values of capacitor. The majority of applications for this regulator involve large changes in load current so the output capacitor must supply the instantaneous load current. The ESR of the output capacitor causes an immediate drop in output voltage given by: VIN (optional) VOUT VIN C1 VOUT CS5205-X C2 Gnd Figure 2b. Protection diode scheme for fixed output regulators. Output Voltage Sensing Since the CS5205-X is a three terminal regulator, it is not possible to provide true remote load sensing. Load regulation is limited by the resistance of the conductors connecting the regulator to the load. For best results the fixed regulators should be connected as shown in Figure 3. ÆV = ÆI ´ ESR VIN For microprocessor applications it is customary to use an output capacitor network consisting of several tantalum and ceramic capacitors in parallel. This reduces the overall ESR and reduces the instantaneous output voltage drop under load transient conditions. The output capacitor network should be as close as possible to the load for the best results. VOUT VIN RC conductor parasitic resistance CS5205-X RLOAD Gnd Protection Diodes When large external capacitors are used with a linear regulator it is sometimes necessary to add protection diodes. If the input voltage of the regulator gets shorted, the output capacitor will discharge into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage and the rate at which VIN drops. In the CS5205-X family of linear regulators, the discharge path is through a large junction and protection diodes are not usually needed. If the regulator is used with large values of output capacitance and the input voltage is instantaneously shorted to ground, damage can occur. In this case, a diode connected as shown in Figures 2a and 2b is recommended. IN4002 VIN C1 For the adjustable regulator, the best load regulation occurs when R1 is connected directly to the output pin of the regulator as shown in Figure 4. If R1 is connected to the load, RC is multiplied by the divider ratio and the effective resistance between the regulator and the load becomes ( RC ´ R1 + R2 R1 ) RC = conductor parasitic resistance VIN (optional) VOUT VIN Figure 3. Conductor parasitic resistance can be minimized with the above grounding scheme for fixed output regulators. VOUT RC VOUT VIN CS5205-1 CS5205-1 conductor parasitic resistance RLOAD R1 Adj R1 C2 Adj R2 CAdj R2 Figure 2a. Protection diode scheme for adjustable output regulator. Figure 4. Grounding scheme for the adjustable output regulator to minimize parasitics. 5 CS5205-1,-3,-5 Applications Information: continued CS5205-1,-3,-5 Applications Information: continued 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. Calculating Power Dissipation and Heat Sink Requirements The CS5205-X series of linear regulators includes thermal shutdown and safe operating area circuitry to protect the device. High power regulators such as these usually operate at high junction temperatures so it is important to calculate the power dissipation and junction temperatures accurately to ensure that an adequate heat sink is used. Each material in the heat flow path between the IC and the outside environment has a thermal resistance. Like series electrical resistances, these resistances are summed to determine RQJA, the total thermal resistance between the junction and the surrounding air. The case is connected to VOUT on the CS5205-X, electrical isolation may be required for some applications. Thermal compound should always be used with high current regulators such as these. 1. Thermal Resistance of the junction to case, RQJC (¡C/W) 2. Thermal Resistance of the case to Heat Sink, RQCS (¡C/W) The thermal characteristics of an IC depend on the following four factors: 3. Thermal Resistance of the Heat Sink to the ambient air, RQSA (¡C/W) 1. Maximum Ambient Temperature TA (¡C) 2. Power dissipation PD (Watts) These are connected by the equation: 3. Maximum junction temperature TJ (¡C) RQJA = RQJC + RQCS + RQSA 4. Thermal resistance junction to ambient RQJA (C/W) The value for RQJA is calculated using equation (3) and the result can be substituted in equation (1). These four are related by the equation TJ = TA + PD ´ RQJA The value for RQJC is normally quoted as a single figure for a given package type based on an average die size. For a high current regulator such as the CS5205-X the majority of the heat is generated in the power transistor section. The value for RQSA depends on the heat sink type, while RQCS depends on factors such as package type, heat sink interface (is an insulator and thermal grease used?), and the contact area between the heat sink and the package. Once these calculations are complete, the maximum permissible value of RQJA can be calculated and the proper heat sink selected. For further discussion on heat sink selection, see application note ÒThermal Management for Linear Regulators.Ó (1) The maximum ambient temperature and the power dissipation are determined by the design while the maximum junction temperature and the thermal resistance depend on the manufacturer and the package type. The maximum power dissipation for a regulator is: PD(max)={VIN(max)ÐVOUT(min)}IOUT(max)+VIN(max)IQ (3) (2) 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 IQ is the maximum quiescent current at IOUT(max). 6 CS5205-1,-3,-5 Package Specification PACKAGE DIMENSIONS IN mm(INCHES) PACKAGE THERMAL DATA Thermal Data RQJC RQJA typ typ 3L TO-220 1.6 50 3L D2PAK 1.6 10 - 50* ûC/W ûC/W *Depending on thermal properties of substrate. RQJA = RQJC + RQCA 3 Lead D2PAK (DP) 3 Lead TO-220 (T) Straight 10.31 (.406) 10.05 (.396) 1.40 (.055) 1.14 (.045) 1.68 (.066) 1.40 (.055) 4.83 (.190) 4.06 (.160) 10.54 (.415) 9.78 (.385) 6.55 (.258) 5.94 (.234) 1.40 (.055) 1.14 (.045) 8.53 (.336) 8.28 (.326) 3.96 (.156) 3.71 (.146) 2.87 (.113) 2.62 (.103) 15.75 (.620) 14.73 (.580) 2.74(.108) 2.49(.098) 14.99 (.590) 14.22 (.560) 1.40 (.055) 1.14 (.045) 2.79 (.110) 2.29 (.090) 0.91 (.036) 0.66 (.026) 2.54 (.100) REF 1.52 (.060) 1.14 (.045) 14.22 (.560) 13.72 (.540) .254 (.010) REF 6.17 (.243) REF 1.40 (.055) 1.14 (.045) 4.57 (.180) 4.31 (.170) 0.10 (.004) 0.00 (.000) 1.02 (.040) 0.63 (.025) 0.56 (.022) 0.38 (.014) 2.79 (.110) 2.29 (.090) 5.33 (.210) 4.83 (.190) 2.92 (.115) 2.29 (.090) Ordering Information Part Number CS5205-1GT3 CS5205-1GDP3 CS5205-1GDPR3 CS5205-3GT3 CS5205-3GDP3 CS5205-3GDPR3 CS5205-5GT3 Rev. 6/12/97 Type 5A, adj. output 5A, adj. output 5A, adj. output Description 3 L TO-220 Straight 3 L D2PAK 3 L D2PAK (tape & reel) 5A, 3.3V output 3 L TO-220 Straight 5A, 3.3V output 3 L D2PAK 5A, 3.3V output 3 L D2PAK (tape & reel) 5A, 5V output 3 L TO-220 Straight Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. 7 © 1999 Cherry Semiconductor Corporation