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IP1845A Dataheets PDF



Part Number IP1845A
Manufacturers Seme LAB
Logo Seme LAB
Description CURRENT MODE REGULATING PULSE WIDTH MODULATORS
Datasheet IP1845A DatasheetIP1845A Datasheet (PDF)

LAB TOP VIEW COMP 1 V FB 2 I SENSE 3 R T /C T 4 8 7 6 5 SEME IP1844A SERIES IP1845A SERIES VREF VCC OUTPUT GROUND CURRENT MODE REGULATING PULSE WIDTH MODULATORS FEATURES • • • • • • Guaranteed ±1% reference voltage tolerance Accurate oscillator discharge current Guaranteed ±10% frequency tolerance Low start–up current (<500 mA) Under voltage lockout with hysteresis Output state completely defined for all supply and input conditions • Interchangeable with IP and UC1844/5 series for improved o.

  IP1845A   IP1845A


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LAB TOP VIEW COMP 1 V FB 2 I SENSE 3 R T /C T 4 8 7 6 5 SEME IP1844A SERIES IP1845A SERIES VREF VCC OUTPUT GROUND CURRENT MODE REGULATING PULSE WIDTH MODULATORS FEATURES • • • • • • Guaranteed ±1% reference voltage tolerance Accurate oscillator discharge current Guaranteed ±10% frequency tolerance Low start–up current (<500 mA) Under voltage lockout with hysteresis Output state completely defined for all supply and input conditions • Interchangeable with IP and UC1844/5 series for improved operation • 500kHz Oscillator operation 250kHz Output operation J Package – 8 Pin Ceramic DIP N Package – 8 Pin Plastic DIP D-8 Package – 8 Pin Plastic (150) SOIC TOP VIEW COMP 1 N/C 2 14 13 12 11 10 9 8 VREF N/C VCC VC OUTPUT GROUND POWER GROUND V FB 3 N/C 4 I SENSE 5 N/C 6 R T /C T 7 D-14 Package – 14 Pin Plastic (150) SOIC Part Number IP1844A IP2844A IP3844A IP1845A IP2845A IP3845A J–Pack 8 Pin N–Pack 8 Pin D–8 8 Pin D–14 14 Pin Order Information Temp. Range -55 to +125°C -25 to +85°C 0 to +70°C -55 to +125°C -25 to +85°C 0 to +70°C Note: To order, add the package identifier to the part number. eg. IP1844AD–14 IP3845AJ ABSOLUTE MAXIMUM RATINGS (Tcase = 25°C unless otherwise stated) VCC IO Supply Voltage Output Current Output Energy Analog Inputs Error Amp Output Sink Current Power Dissipation Derate @ Tamb > 50°C Power Dissipation Derate @ Tamb > 50°C Power Dissipation Derate @ Tcase > 25°C Storage Temperature Range Lead Temperature (low impedance source) (ICC < 30mA) (capacitive load) (pins 2 and 3) Tamb = 25°C Tcase = 25°C Tcase = 25°C J, N Packages D Package J, N Packages +30V Self limiting ±1A 5µJ –0.3V to +VCC 10mA 1W 10mW/°C 725mW 7.25mW/°C 2W 16mW/°C –65 to 150°C +300°C Prelim. 2/95 PD PD PD TSTG TL (soldering, 10 seconds) Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. LAB DESCRIPTION SEME IP1844A SERIES IP1845A SERIES The IP1844A/IP1845A series of switching regulator control circuits contain all the functions necessary to implement off-line, current mode switching regulators, using a minimum number of external parts. Functions included are voltage reference, error amplifier, current sense comparator, oscillator, totem-pole output driver and under-voltage lockout circuitry. In addition the IP1844A and IP1845A series of devices have a toggle flip-flop which blanks the output on every second clock pulse, thereby ensuring that the duty cycle never exceeds 50%. For applications requiring more flexible control, all devices feature an on-chip trimmed oscillator discharge current, allowing accurate control to maximum-duty-cycle by selection of timing components. This can be beneficial even when using the IP1844A or IP1845A series, as it allows optimum safety margins to be designed into the application. Although pin compatible with the standard IP1844/5 parts these devices offer improved performance in several areas. They also offer tighter specification and improved performance over the IP and UC1844/5 series, whilst retaining complete compatibility. BLOCK DIAGRAM VCC 7/12 34V G ND 5/9 UNDER–VOLTAGE LOCKOUT ENABLE REFERENCE 5V REGULATOR INTERNAL BIAS 2.5V REG 8/14 VREF 16V (8.4V) 6V (0.5V) S R 3.6V R T /CT 4/7 VREF STATUS LATCH 7/11 VC OSCILLATOR Q T ERROR AMP S R R 1V CURRENT SENSE COMPARATOR PWM LATCH TOGGLE FLIP FLOP * 6/10 OUTPUT 5/8 POW ER GROUND 2R V FB C OMP I SENSE 2/3 1/1 * 1844A and 1845A series only. Values in brackets are for IP1845 series. PIN NUMBERS 1st Number – N, J and 8 Pin D Packages 2nd Num ber – 14 Pin D Package. 3/5 RECOMMENDED OPERATING CONDITIONS VCC IO Supply Voltage 1 Output Current Analog Inputs (pins 2 and 3) IP1844A , IP1845A IP2844A , IP2845A IP3844A , IP3845A Error Amp Output Sink Current Operating Ambient Temperature Range ≤ 30V 0 to ±200mA –0.3V to 3V 0 to 2mA –55 to 125°C –25 to 85°C 0 to 70°C Notes: 1. Lower limit set by under voltage lockout specification. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 2/95 Semelab plc. LAB Parameter Output Voltage Input Regulation Output Regulation Temperature Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Current Frequency Voltage Stability Temperature Stability Amplitude Discharge Current Line, Load, Temp f = 10Hz to 10kHz TJ = 25°C TJ = 125°C @ 1000Hrs VREF = 0 SEME IP1844A SERIES IP1845A SERIES ELECTRICAL CHARACTERISTICS (Over Full Operating Temperature Range unless otherwise stated) Test Conditions 1 REFERENCE SECTION IO = 1mA VCC = 12V to 25V IO = 1mA to 20mA TJ = 25°C IP1844A , IP1845A IP2844A , IP2845A Min. Typ. Max. 4.95 5.00 6 6 0.2 4.90 50 5 30 80 25 160 5.05 20 25 0.4 5.10 Min. 4.90 IP3844A IP3845A Typ. 5.00 6 6 0.2 Max. Units 5.10 20 25 0.4 5.18 V mV mV °C V µV 25 160 mV mA 4.82 50 5 30 80 OSCILLATOR SECTION TJ = 25°C VCC = 12V to 25V ∆TA = Min to Max VPIN4 Peak to Peak TJ = 25°C ∆TA = Min to Max (Note 2) 47 52 0.2 5 1.7 57 1 47 52 0.2 5 1.7 57 1 kHz % % V 7.8 7 2.45 8.3 8.8 9 7..


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