CS3972

CS3972 CHERRY | Alldatasheet

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Technical content

Features

I 75VMAX, 2APEAK Internal Switch I 3V to 60V Input Voltage Range I 6mA Input Supply Current I 1.24V Precision Reference I 40kHz Switching Frequency I Variable Current Limit with External Voltage Clamp I Under-Voltage Protection I Over-Temperature Protection I External Synchronization Package Options 5L TO-220 Tab (Gnd) 8L PDIP 1Gnd VC VFB NC VSW VIN 1V C 2V FB

3 Gnd

1 GndNC

The CS3972 is a 1.25A, 60V , current mode, high efficiency, switching regulator circuit. It can be config- ured in buck, boost, forward, iso- lated and non-isolated topologies, using a single-ended switch. The IC contains a 1.25A high effi- ciency output switch, precision bandgap reference, voltage regula- tor, error amplifier, oscillator, con- trol, and protection circuitry. Output transistor efficiency is achieved by keeping the switch in quasi-saturation when it is on. This minimizes the switch turn-off delay time and power dissipation, an important consideration for applications with wide ranging loads. The precision reference is internally trimmed to 1.24V , while the oscilla- tor frequency is internally trimmed to 40kHz. The on board 2.3V regu- lator powers the internal circuitry. By keeping the voltage regulator at 2.3V , the IC is able to operate down to 3V and maintain a constant input supply current of 6mA(typ). Synchronization mode is achieved by applying a pulsating V C voltage of less than 0.2V with a duration of about 0.5µs to V C pin. The switch- ing frequency can be adjusted from 50kHz to 70kHz. The IC's synchro- nization mode is set externally. Protection circuitry includes a vari- able current limit with external voltage clamp, under-voltage and over-temperature protection. Rev. 6/23/99 Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com A Company ®

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Lead Temperature Soldering Electrical Characteristics: For 3V≤VCC≤60V , -40°C≤TA≤125°C unless otherwise specified. I Reference Voltage V C=0.8V; VFB=VREF 1.214 1.244 1.274 V Line Regulation V C=0.8V; VFB=VREF, 3V≤VIN≤60V 0.03 %/V Feedback Input Current V C=0.8V; VFB=VREF 350 1100 nA Minimum Input Voltage V C=VFB=VREF 2.6 3.0 V Supply Current V C=0.6V; 3V≤VIN≤60V 6.0 9.0 mA Supply Current Increase during switch on time V C=open, 1.0V≤VFB≤1.5V 25 mA/A Switching Frequency V C=VFB=VREF; VSW=15V 33 40 47 kHz Maximum Duty Cycle V C=2V; VFB=open, VSW=15V 92 % VC Threshold V FB=open; VSW =15V , 0.60 0.90 1.25 V duty cycle=0% I Error Amplifier Transconductance V C=0.8V; VFB=VREF, ∆IC=±25µA 2400 4400 7000 µmho Source/Sink Current V C=1.5V 120 200 400 µA High Voltage Clamp V FB=1.0V 2.0 V Low Voltage Clamp V FB=1.5V 0.38 V Gain 0.9V ≤VC≤1.4V , VFB=VREF 800 V/V I Output Switch Breakdown Voltage V C=0.5V; 3V≤VIN≤60V , IOUT=5mA 75 90 V On Resistance V C=open, VFB=0.8V , IOUT=1.25A 0.6 1.0 Ω Control Voltage to Switch 1.2V≤VC≤1.8V 2 A/V Current Transconductance Current Limit Duty Cycle ≤50%, TJ≥25°C 1.25 3.00 A Duty Cycle≤50%, TJ<25°C 1.25 3.50 A Duty Cycle=80% 1.00 2.50 A Duty Cycle=80% (Note 1) 0.50 2.50 A Note 1: 16 lead SO wide package only.

PACKAGE PIN # PIN SYMBOL FUNCTION Typical Performance Characteristics 1.274 1.264 1.254 1.244 1.234 1.224 1.214 -50 -25 -0 25 50 75 100 125 150 Temperature (°C) Reference Voltage (V) Reference Voltage vs. Temperature -50 -25 -0 25 50 75 100 125 150 Temperature (°C) Frequency (kHz) Switching Frequency vs. Temperature 100 Switch Current (A) Driver Current (mA) 1.8 2.0 Driver Current vs. Switch Current -50 -25 -0 25 50 75 100 125 150 Junction Temperature (°C) Duty Cycle (%) Maximum Duty Cycle 1.6 1.4 1.2 1.0 0.8 0.6 0 0.50 1.00 1.25 1.75 Switch Current (A) Switch Saturation Voltage (V) 0.4 0.2 2.00.25 0.75 1.50 Tj=25°C Switch Saturation Voltage 16L 5L 8L SO Wide TO-220 PDIP 16 3 1 Gnd Logic and power ground on TO-220. Logic ground only on 8L PDIP . 21 2 V C Control voltage can be used for frequency compensation, cur- rent limit threshold, frequency synchronization, and soft start. 32 3 V FB Feedback voltage is the negative input to the error amplifier. 1,4,5,6,7,8, 4 NC No connection. 10,12,15 95 5 V IN Supply input voltage with a range of 3V to 60V . 11 6 E 1 Emitter One is a power ground which should always be con- nected to logic ground since it is used as the negative input to the current sense amp. 13 4 7 V SW Collector of internal 75V NPN power switch. 14 8 E 2 Emitter Two is a power ground which can be left disconnected to reduce the switch rating to 625mA. CS3972

RΘJC typ 1.7 52 23 ˚C/W RΘJA typ 50 100 105 ˚C/W D Lead Count Metric English Max Min Max Min 8 Lead PDIP 10.16 9.02 .400 .355 16 Lead SO Wide 10.50 10.10 .413 .398 CS3972 Package Specification PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA Plastic DIP (N); 300 mil wide 0.39 (.015) MIN. 1.14 (.045) D Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. .203 (.008) .356 (.014) REF: JEDEC MS-001 3.68 (.145) 2.92 (.115) 8.26 (.325) 7.62 (.300) 7.11 (.280) 6.10 (.240) .356 (.014) .558 (.022) Surface Mount Wide Body (DW); 300 mil wide 1.27 (.050) BSC 7.60 (.299) 7.40 (.291) 10.65 (.419) 10.00 (.394) D 0.32 (.013) 0.23 (.009) 1.27 (.050) 0.40 (.016) REF: JEDEC MS-013 2.49 (.098) 2.24 (.088) 0.51 (.020) 0.33 (.013) 2.65 (.104) 2.35 (.093) 0.30 (.012) 0.10 (.004)

Ordering Information

Rev. 6/23/99 CS3972 Part Number Description CS3972YN8 8L PDIP CS3972YDW16 16L SO Wide CS3972YDWR16 16L SO Wide (tape & reel) CS3972YT5 TO-220 Straight CS3972YTVA5 TO-220 Vertical CS3972YTHA5 TO-220 Horizontal © 1999 Cherry Semiconductor Corporation Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information.

5 Lead TO-220 (T) Straight

2.87 (.113) 2.62 (.103) 6.93(.273) 6.68(.263) 9.78 (.385) 10.54 (.415) 1.02(.040) 0.63(.025) 1.83(.072) 1.57(.062) 0.56 (.022) 0.36 (.014) 2.92 (.115) 2.29 (.090) 1.40 (.055) 4.06 (.160) 6.55 (.258) 5.94 (.234) 14.22 (.560) 0.76 (.030) 3.71 (.146) 3.96 (.156) 14.99 (.590) 14.22 (.560)

5 Lead TO-220 (TV A) Vertical

1.68 7.51 (.296) 1.78 (.070) 4.34 (.171) 0.56 (.022) 0.36 (.014) 1.40 (.055) 1.14 (.045) 4.83 (.190) 4.06 (.160) 14.99 (.590) 14.22 (.560) 2.92 (.115) 2.29 (.090) .94 (.037) .69 (.027) 8.64 (.340) 7.87 (.310) 6.80 (.268) 10.54 (.415) 9.78 (.385) 2.87 (.113) 2.62 (.103) 6.55 (.258) 5.94 (.234) 3.96 (.156) 3.71 (.146)

5 Lead TO-220 (THA) Horizontal

0.81(.032) 1.70 (.067) 6.81(.268) 1.40 (.055) 1.14 (.045) 5.84 (.230) 6.60 (.260) 6.83 (.269) 0.56 (.022) 0.36 (.014) 10.54 (.415) 9.78 (.385) 6.55 (.258) 5.94 (.234) 3.96 (.156) 3.71 (.146) 1.68 (.066) TYP 14.99 (.590) 14.22 (.560) 2.77 (.109) 2.29 (.090) 2.92 (.115) 4.83 (.190) 4.06 (.160) 2.87 (.113) 2.62 (.103)