IP1844A SERIES IP1845A SERIES SEME LAB TOP VIEW COMP 1 8 VREF V FB 2 7 VCC I SENSE 3 6 OUTPUT R T /C T 4 5 GROUND CURRENT MODE REGULATING PULSE WIDTH MODULATORS J Package – 8 Pin Ceramic DIP N Package – 8 Pin Plastic DIP D-8 Package – 8 Pin Plastic (150) SOIC 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 TOP VIEW COMP 1 14 VREF N/C 2 13 N/C V FB 3 12 VCC N/C 4 11 VC I SENSE 5 10 OUTPUT 6 9 GROUND R T /C T 7 8 POWER GROUND N/C D-14 Package – 14 Pin Plastic (150) SOIC Order Information Part Number IP1844A IP2844A IP3844A IP1845A IP2845A IP3845A J–Pack 8 Pin ✔ ✔ ✔ ✔ ✔ ✔ N–Pack 8 Pin ✔ ✔ ✔ ✔ D–8 8 Pin ✔ ✔ ✔ ✔ D–14 14 Pin ✔ ✔ ✔ ✔ 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 Supply Voltage IO 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 PD PD PD TSTG TL Semelab plc. (low impedance source) (ICC < 30mA) (capacitive load) (pins 2 and 3) Tamb = 25°C J, N Packages Tcase = 25°C D Package Tcase = 25°C J, N Packages (soldering, 10 seconds) Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. +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 IP1844A SERIES IP1845A SERIES SEME LAB DESCRIPTION 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 UNDER–VOLTAGE LOCKOUT 34V REFERENCE 5V REGULATOR ENABLE G ND 5/9 16V (8.4V) 6V (0.5V) 8/14 VREF INTERNAL BIAS REG 2.5V VREF STATUS LATCH S 7/11 R VC 3.6V R T /CT 4/7 6/10 OSCILLATOR Q T ERROR AMP V FB 1/1 I SENSE 3/5 5/8 POW ER GROUND S 2R 2/3 C OMP TOGGLE FLIP FLOP * OUTPUT R R 1V PWM LATCH CURRENT SENSE COMPARATOR * 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. RECOMMENDED OPERATING CONDITIONS VCC Supply Voltage 1 IO Output Current Analog Inputs ≤ 30V 0 to ±200mA –0.3V to 3V (pins 2 and 3) 0 to 2mA Error Amp Output Sink Current Operating Ambient Temperature Range IP1844A , IP1845A IP2844A , IP2845A IP3844A , IP3845A –55 to 125°C –25 to 85°C 0 to 70°C Notes: 1. Lower limit set by under voltage lockout specification. Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 2/95 IP1844A SERIES IP1845A SERIES SEME LAB ELECTRICAL CHARACTERISTICS (Over Full Operating Temperature Range unless otherwise stated) Test Conditions 1 Parameter IP1844A , IP1845A IP2844A , IP2845A Min. Typ. Max. Min. IP3844A IP3845A Typ. 4.95 4.90 5.00 5.10 Max. Units REFERENCE SECTION Output Voltage IO = 1mA Input Regulation Output Regulation TJ = 25°C 5.00 5.05 VCC = 12V to 25V 6 20 6 20 IO = 1mA to 20mA 6 25 6 25 0.2 0.4 0.2 0.4 Temperature Stability Total Output Variation Line, Load, Temp Output Noise Voltage f = 10Hz to 10kHz Long Term Stability TJ = 125°C @ 1000Hrs Output Short Circuit Current 4.90 TJ = 25°C 5.10 4.82 5 25 30 80 160 47 52 57 1 mV mV °C V µV 50 50 VREF = 0 5.18 V 5 25 mV 30 80 160 mA 47 52 57 kHz 0.2 1 % OSCILLATOR SECTION Frequency TJ = 25°C Voltage Stability VCC = 12V to 25V 0.2 Temperature Stability ∆TA = Min to Max 5 5 % Amplitude VPIN4 Peak to Peak 1.7 1.7 V (Note 2) TJ = 25°C Discharge Current 7.8 ∆TA = Min to Max 8.8 7.8 9 7 2.50 2.55 2.42 –0.3 –1 8.3 7 8.3 8.8 9 mA ERROR AMP SECTION Input Voltage VPIN1 = 2.5V 2.45 Input Bias Current Open Loop Voltage Gain VO = 2V to 4V Unity Gain Bandwidth Supply Voltage VCC = 12V to 25V Rejection 2.50 2.58 V –0.3 –2 µA 65 90 65 90 dB 0.7 1 0.7 1 MHz 60 70 60 70 dB 2 6 2 6 Output Sink Current VPIN2 = 2.7V VPIN1 = 1.1V Output Source Current VPIN2 = 2.3V VPIN1 = 5V –0.5 –0.8 –0.5 –0.8 VOUT High VPIN2 = 2.3V RL = 15kΩ 5 6 5 6 VOUT Low VPIN2 = 2.7V RL = 15kΩ 0.7 1.1 0.7 mA 1.1 V NOTES 1. Test Conditions unless otherwise stated: VCC = 15V* , RT = 10kΩ , CT = 3.3nF , f = 52kHz. *Adjust VCC above start threshold before setting at required level. 2. Output frequency is half the oscillator frequency. All specifications apply over the full operating temperature range unless otherwise stated. (See Ordering Information for further details). Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 2/95 IP1844A SERIES IP1845A SERIES SEME LAB ELECTRICAL CHARACTERISTICS (Over Full Operating Temperature Range unless otherwise stated) Test Conditions 1 Parameter IP1844A , IP1845A IP2844A , IP2845A Min. Typ. Max. Min. IP3844A IP3845A Typ. 2.85 3 3.15 2.85 3 3.15 V/V 0.9 1 1.1 0.9 1 1.1 V 60 70 60 70 Max. Units CURRENT SENSE SECTION Gain See Notes 2,3 Maximum Input Signal VPIN1 = 5V Supply Voltage (Note 2) VC = 12V to 25V Rejection dB Input Bias Current –2 –10 –2 –10 µA Delay to Output 150 300 150 300 ns ISINK = 20mA 0.1 0.4 0.1 0.4 ISINK = 200mA 1.5 2.2 1.5 2.2 OUTPUT SECTION Output Low Level Output High Level ISOURCE = 20mA 13 13.5 13 13.5 ISOURCE = 200mA 12 13.5 12 13.5 V Rise Time CL = 1nF 50 150 50 150 Fall Time CL = 1nF 50 150 50 150 UVLO Saturation VCC = 6V 0.7 1.1 0.7 1.1 IL = 1mA V ns V UNDER–VOLTAGE LOCKOUT SECTION Upper Threshold IP1844A Series 15 16 17 14.5 16 17.5 (VCC) IP1845A Series 7.8 8.4 9 7.8 8.4 9 Lower Threshold IP1844A Series 9 10 11 8.5 10 11.5 (VCC) IP1845A Series 7 7.6 8.2 7 7.6 8.2 0.3 0.5 0.3 0.5 V V TOTAL STANDBY CURRENT Start–up Current Operating Supply VPIN2 = 0V IP1844A Series 11 15 11 15 Current VPIN3 = 0V IP1845A Series 14 17 14 17 VCC Zener Voltage ICC = 25mA 30 34 40 30 34 40 47 48 50 46 48 50 mA mA V PWM SECTION Maximum Duty Cycle Minimum Duty Cycle 0 0 % NOTES 1. Test Conditions unless otherwise stated: VCC = 15V* , RT = 10kΩ , CT = 3.3nF , f = 52kHz. *Adjust VCC above start threshold before setting at required level. 2. Parameter measured at trip point of latch with VPIN2 = 0V 3. Gain defined as: All specifications apply over the full operating temperature range unless otherwise stated. (See Ordering Information for further details). Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. ∆VPIN1 ∆VPIN3 0 ≤ VPIN3 ≤ 0.8 A= Prelim. 2/95 IP1844A SERIES IP1845A SERIES SEME LAB APPLICATIONS INFORMATION Oscillator Waveforms and Maximum Duty Cycle LARGE R T SMALL C T VPIN4 (VPIN7 for 14 pin D package) INTERNAL CLOCK V REF OUTPUT – Max. Duty Cycle VPIN6 (VPIN10 for 14 pin D package) 8 RT RTCT 4 LARGE C T SMALL R T CT GND VPIN4 (VPIN7 for 14 pin D package) 5 INTERNAL CLOCK OUTPUT – Max. Duty Cycle VPIN6 (VPIN10 for 14 pin D package) Oscillator timing capacitor C T is charged by V REF tc ≈ 0.55 RTCT through RT and discharged by an internal current source. .0063 RT – 2.3 During the discharge time, the internal clock signal td ≈ RTCT Rn .0063 – 4 blanks the output to the low state. Selection of RT and 1 CT therefore determines both oscillator frequency and Resultant frequency f = (tc + td) maximum duty cycle. Charge and discharge times are determined by the formulae: ( ) For RT > 5kΩ, Resultant frequency f ≈ 1.8 (RTCT) Open–Loop Laboratory Test Fixture VREF RT 4.7kΩ VCC 2N2222 100k Ω 1kΩ ERROR AMP ADJUST 5kΩ ISENSE ADJUST 1 COMP VREF 8 2 VFB VCC 7 3 ISENSE O/P 6 4 R T /C T GND 5 0.1 µF 0.1 µF 1k Ω 1kW OUTPUT 4.7kΩ GROUND CT High peak current associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5K potentiometer are used to sample the oscillator wave form and apply an adjustable ramp to pin 3. Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. Prelim. 2/95 IP1844A SERIES IP1845A SERIES SEME LAB TYPICAL PERFORMANCE CHARACTERISTICS ERROR AMPLIFIER OPEN-LOOP FREQUENCY RESPONSE OUTPUT SATURATION CHARACTERISTICS 100 VO LT AG E G AIN TA = –55˚C 2 SOURCE SAT ( VCC- VOH) 1 0 60 –45 (˚) TA = 25˚C 80 40 PH ASE VCC = 15V 3 (dB) SAT U R AT IO N VO L TAG E (V) 4 –90 f 20 –135 AV 0 –180 SINK SAT (VOL ) 0 .01 .02 .03 .04 .05 .07 .1 .2 .3 .4 .5 .7 10 1.0 100 1k OUTPUT CURRENT, SOURCE / SINK (A) 20 20 15 15 10 0.5 1M 10M 10 0.5 0 5 10 15 20 0 0 VCC (V) Semelab plc. 100k UNDER VOLTAGE LOCKOUT 1845A SERIES I CC (m A) I CC (m A) UNDER VOLTAGE LOCKOUT 1844A SERIES 0 10k FREQUENCY (Hz) Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612. 2.5 5 7.5 10 VCC (V) Prelim. 2/95