CS52015-3 CS52015-3 1.5A, 3.3V Fixed Linear Regulator Description The CS52015-3 linear regulator provides 1.5A at 3.3V with an output voltage accuracy of ±1.5%. The regulator is intended for use as a post regulator and microprocessor supply. The fast loop response and low dropout voltage make this regulator ideal for applications where low voltage operation and good transient response are important. The circuit is designed to operate with dropout voltages less than Features 1.4V at 1.5A output current. The maximum quiescent current is only 10mA at full load. Device protection includes overcurrent and thermal shutdown. The CS52015-3 is pin compatible with the LT1086 family of linear regulators but has lower dropout voltage. The regulator is available in TO220, surface mount D2, and SOT-223 packages. ■ Output Current to 1.5A ■ Output Accuracy to ±1.5% Over Temperature ■ Dropout Voltage (typical) 1.05V @ 1.5A ■ Fast Transient Response ■ Fault Protection Current Limit Thermal Shutdown Application Diagram Package Options VOUT VIN 3.3V @ 1.5A 3L TO-220 3L D2PAK Tab (VOUT) Tab (VOUT) CS52015-3 Gnd 10 mF 5V 1 22mF 5V 3L SOT-223 1 Tab (VOUT) CS52015 -3 1 Gnd 2 VOUT (tab) 3 VIN 1 Consult factory for other fixed output voltage options. 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. 2/17/98 1 A ¨ Company CS52015-3 Absolute Maximum Ratings Supply Voltage, VIN .....................................................................................................................................................................7V 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 ESD Damage Threshold............................................................................................................................................................2kV Electrical Characteristics: CIN = 10µF, COUT = 22µF Tantalum, VOUT + VDROPOUT < VIN < 7V, 0¡C ² TA ² 70¡C, TJ ² +150¡C, unless otherwise specified, Ifull load = 1.5A. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 3.250 (-1.5%) 3.300 3.350 (+1.5%) V ■ Fixed Output Voltage Output Voltage (Notes 1 and 2) VINÐVOUT=1.5V 0²IOUT²1.5A Line Regulation 2V²VINÐVOUT²3.7V; IOUT=10mA 0.02 0.20 % Load Regulation (Notes 1 and 2) VINÐVOUT=2V; 10mA ²IOUT²1.5A 0.04 0.4 % Dropout Voltage (Note 3) IOUT=1.5A 1.05 1.4 V Current Limit VINÐVOUT=3V 1.6 3.1 A Quiescent Current IOUT=10mA 5.0 10.0 mA Thermal Regulation (Note 4) 30ms pulse; TA=25¡C 0.002 0.020 %/W Ripple Rejection (Note 4) f=120Hz; IOUT=1.5A; VINÐVOUT=3V; VRIPPLE=1VP-P 80 Thermal Shutdown (Note 5) 150 180 Thermal Shutdown Hysteresis (Note 5) 25 dB 210 ¡C ¡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 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. Note 4: Guaranteed by design, not tested in production. Note 5: Thermal shutdown is 100% functionally tested in production. Package Pin Description PACKAGE PIN # PIN SYMBOL FUNCTION D2PAK TO-220 SOT-223 1 1 1 Gnd Ground connection 2 2 2 VOUT Regulated output voltage (case). 3 3 3 VIN Input voltage 2 CS52015-3 Block Diagram V OUT V IN Output Current Limit Thermal Shutdown - + Error Amplifier Bandgap Gnd Typical Performance Characteristics 1.05 0.10 0.08 TCASE 0ûC Output Voltage Deviation (%) V Drop Out (V) 1.00 0.95 TCASE 25ûC 0.90 0.85 0.80 TCASE 125ûC 0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06 -0.08 -0.10 -0.12 0 0.75 0 300 600 900 1200 10 20 30 40 50 60 70 80 90 100 110 120 130 TJ (°C) 1500 IOUT (mA) Dropout Voltage vs Output Current Output Voltage vs. Temperature 3.5 85 3.3 3.1 65 2.9 55 2.7 ISC(A) Ripple Rejection (dB) 75 TCASE = 25°C IOUT = 1.5A (VIN Ð VOUT) = 3V VRIPPLE = 1.0VPP 45 35 2.5 2.3 2.1 1.9 25 1.7 15 101 102 103 104 105 1.5 106 1.0 1.5 Frequency (Hz) Ripple Rejection vs. Frequency 2.0 2.5 3.0 3.5 4.0 4.5 VIN - VOUT (V) Short Circuit Current vs VIN-VOUT 3 5.0 5.5 6.0 6.5 7.0 0.100 Output Voltage Deviation (%) 200 100 0 COUT =CIN =22mF Tantalum -100 -200 Load Step (mA) CS52015-3 Voltage Deviation (mV) Typical Performance Characteristics 1500 0.075 0.050 TCASE = 125°C TCASE = 25°C 0.025 750 TCASE = 0°C 0.000 0 0 1 2 3 4 5 6 7 8 9 0 10 1 Output Current (A) Time mS Transient Response 2 Load Regulation vs. Output Current Applications Information The CS52015-3 linear regulator provides a 3.3V output voltage at currents up to 1.5A. The regulator is protected against overcurrent conditions and includes thermal shutdown. The CS52015-3 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. 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 CS52015-3 linear regulator, 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 Figure 1 is recommended. Stability Considerations 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 are 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 manufacturersÕ data sheet provides this information. A 22µF tantalum capacitor will work for most applications, but with high current regulators such as the CS52015-3 the transient response and stability improve with higher values of capacitance. 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: IN4002 VIN VOUT VIN C1 (optional) VOUT CS52015-3 C2 Gnd Figure 1: Protection diode scheme for large output capacitors. ÆV = ÆI ´ ESR Output Voltage Sensing 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. Since the CS52015-3 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 regulator should be connected as shown in Figure 2. 4 IOUT(max) is the maximum output current, for the application RC VIN IQ is the maximum quiescent current at IOUT(max). conductor parasitic resistance 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. VOUT VIN CS52015-3 RLOAD 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. 1. Thermal Resistance of the junction to case, RQJC (¡C/W) 2. Thermal Resistance of the case to Heat Sink, RQCS (¡C/W) Figure 2: Conductor parasitic resistance effects can be minimized with the above grounding scheme for fixed output regulators. 3. Thermal Resistance of the Heat Sink to the ambient air, RQSA (¡C/W) Calculating Power Dissipation and Heat Sink Requirements The CS52015-3 linear regulator includes thermal shutdown and current limit 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. These are connected by the equation: RQJA = RQJC + RQCS + RQSA The value for RQJA is calculated using equation (3) and the result can be substituted in equation (1). The case is connected to VOUT on the CS52015-3, and electrical isolation may be required for some applications. Thermal compound should always be used with high current regulators such as these. The value for RQJC is 3.5ûC/W. For a high current regulator such as the CS52015-3 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 The thermal characteristics of an IC depend on the following four factors: 1. Maximum Ambient Temperature TA (¡C) 2. Power dissipation PD (Watts) 3. Maximum junction temperature TJ (¡C) 4. Thermal resistance junction to ambient RQJA (C/W) These four are related by the equation TJ = TA + PD ´ RQJA (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, 5 CS52015-3 Applications Information: continued PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA 3L 3L 3L Thermal Data TO-220 D2PAK SOT-223 RQJC typ 3.5 3.5 15 ûC/W RQJA typ 50 10 - 50* 156 ûC/W *Depending on thermal properties of substrate. RQJA = RQJC + RQCA 3 Lead TO-220 (T) Straight 4.83 (.190) 4.06 (.160) 10.54 (.415) 9.78 (.385) 6.55 (.258) 5.94 (.234) 1.40 (.055) 1.14 (.045) 3.96 (.156) 3.71 (.146) 2.87 (.113) 2.62 (.103) 3 Lead SOT-223 (ST) 6.70 (.264) 6.30 (.248) 14.99 (.590) 14.22 (.560) 7.30 (.287) 6.70 (.264) 1.52 (.060) 1.14 (.045) 14.22 (.560) 13.72 (.540) 3.15 (.124) 2.95 (.116) 6.17 (.243) REF 3.70 (.146) 3.30 (.130) 1.40 (.055) 1.14 (.045) 1.02 (.040) 0.63 (.025) 2.30 (.090) 1.05 (.041) 0.85 (.033) 0.56 (.022) 0.38 (.014) 2.79 (.110) 2.29 (.090) 0.35 (.014) 0.25 (.010) 1.70 (.067) 1.50 (.060) 5.33 (.210) 4.83 (.190) 2.92 (.115) 2.29 (.090) 0.10 (.004) 0.02 (.001) 0.85 (.033) 0.65 (.026) 1.30 (.051) 1.10 (.043) 10° MAX 4.60 (.181) 3 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) 1.40 (.055) 1.14 (.045) 2.79 (.110) 2.29 (.090) 0.91 (.036) 0.66 (.026) 2.54 (.100) REF 4.57 (.180) 4.31 (.170) .254 (.010) REF 0.10 (.004) 0.00 (.000) Ordering Information Part Number CS52015-3GT3 CS52015-3GDP3 CS52015-3GDPR3 CS52015-3GST3 CS52015-3GSTR3 Rev. 2/17/98 Type 1.5A, 3.3V output 1.5A,3.3V output 1.5A, 3.3V output Description 3 L TO-220 Straight 3 L D2PAK 3 L D2PAK (tape & reel) 1.5A, 3.3V output 3 Lead SOT-223 1.5A, 3.3V output 3 Lead SOT-223 (tape & reel) Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. 6 © 1999 Cherry Semiconductor Corporation CS52015-3 Package Specification