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Part: CS2844LDR14
Category:
Power Management
-> PWM Controllers
-> Current Mode PWM Controllers
Description: Current Mode PWM Control Circuit With 50% Max Duty Cycle
Company: ON Semiconductor
Datasheet: Download CS2844LDR14 datasheet File size : 243 kB
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Datasheet text preview:
CS2844, CS3844, CS2845, CS3845 Current Mode PWM Control Circuit with 50% Max Duty Cycle
The CS3844/45 provides all the necessary features to implement offline fixed frequency currentmode control with a minimum number of external components. The CS3844 family incorporates a new precision temperaturecontrolled oscillator to minimize variations in frequency. An internal toggle flipflop, which blanks the output every other clock cycle, limits the dutycycle range to less than 50%. An undervoltage lockout ensures that VREF is stabilized before the output stage is enabled. In the CS2844/CS3844 turn on occurs at 16 V and turn off at 10 V. In the CS2845/CS3845 turn on is at 8.4 V and turn off at 7.6 V. Other features include low startup current, pulsebypulse current limiting, and a highcurrent totem pole output for driving capacitive loads, such as gate of a power MOSFET. The output is low in the off state, consistent with Nchannel devices. Features · Optimized for OffLine Control · Temp. Compensated Oscillator · 50% Max DutyCycle Clamp · VREF Stabilized Before Output Stage Is Enabled · Low StartUp Current · PulseByPulse Current Limiting · Improved Undervoltage Lockout · Double Pulse Suppression · 1.0% Trimmed Bandgap Reference · High Current Totem Pole Output
http://onsemi.com MARKING DIAGRAMS
8 DIP8 N SUFFIX CASE 626 1 SO8 D SUFFIX CASE 751 1 14 SO14 D SUFFIX CASE 751A 1 16 SO16L DW SUFFIX CASE 751G 1 1 x y A WL, L YY, Y WW, W = 2 or 3 = 4 or 5 = Assembly Location = Wafer Lot = Year = Work Week CSx84yDW AWLYYWW CSx84yD14 AWLYWW CSx84yN AWL YYWW 1 8 384yD ALYW
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8 1
14 1
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ORDERING INFORMATION
See detailed ordering and shipping information in the package dimensions section on page 7 of this data sheet.
© Semiconductor Components Industries, LLC, 2001
1
June, 2001 Rev. 3
Publication Order Number: CS2844/D
CS2844, CS3844, CS2845, CS3845
PIN CONNECTIONS
DIP8 & SO8 COMP VFB Sense OSC 1 8 1 VREF VCC VOUT GND COMP NC VFB NC Sense NC OSC SO14 14 VREF NC VCC VCC Pwr VOUT GND Pwr GND NC NC COMP VFB Sense OSC NC NC 1 SO16L 16 NC VREF VCC VCC Pwr VOUT GND Pwr GND NC
VCC Undervoltage Lockout VCC 34 V Set/ Reset 16 V/10 V (8.4 V/7.6 V) VFB Error Amplifier 5.0 V Reference Internal Bias VREF VCC Pwr
GND
R 2.50 V R
OSC
Oscillator
2R
R 1.0 V Current Sensing Comparator
Sense
+
COMP
VREF Undervoltage Lockout
Toggle FlipFlop
NOR VOUT S R PWM Latch Pwr GND
( ) Indicates CS2845/3845
Figure 1. Block Diagram
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CS2844, CS3844, CS2845, CS3845
MAXIMUM RATINGS*
Rating Supply Voltage (ICC < 30 mA) Supply Voltage (Low Impedance Source) Output Current Output Energy (Capacitive Load) Analog Inputs (VFB, Sense) Error Amp Output Sink Current Package Thermal Resistance, PDIP8 JunctiontoCase, RJC JunctiontoAmbient, RJA Package Thermal Resistance, SO8 JunctiontoCase, RJC JunctiontoAmbient, RJA Package Thermal Resistance, SO14 JunctiontoCase, RJC JunctiontoAmbient, RJA Package Thermal Resistance, SO16L JunctiontoCase, RJC JunctiontoAmbient, RJA Lead Temperature Soldering: 1. 10 second maximum. 2. 60 second maximum above 183°C. *The maximum package power dissipation must be observed. Wave Solder (through hole styles only) (Note 1) Reflow (SMD styles only) (Note 2) Value Self Limiting 30 ±1.0 5.0 0.3 to + 5.5 10 52 100 45 165 30 125 23 105 260 peak 230 peak Unit V A µJ V mA °CW °CW °CW °CW °CW °CW °CW °CW °C °C
ELECTRICAL CHARACTERISTICS (25° TA 85° for CS2844/2845, 0° TA 70° for CS3844/CS3845.
VCC = 15 V*; RT = 10 k, CT = 3.3 nF for sawtooth mode; unless otherwise stated.) CS2844/CS2845 Characteristic Reference Section Output Voltage Line Regulation Load Regulation Temperature Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Oscillator Section Initial Accuracy Voltage Stability Temperature Stability Amplitude Sawtooth Mode, TJ = 25°C 12 VCC 25 V Sawtooth Mode TMIN TA TMAX. Note 3. VOSC (peak to peak) 47 52 0.2 5.0 1.7 57 1.0 47 52 0.2 5.0 1.7 57 1.0 kHz % % V TJ = 25°C, IREF = 1.0 mA 12 VCC 25 V 1.0 IREF 20 mA Note 3. Line, Load, Temperature. Note 3. 10 Hz f 10 kHz, TJ = 25°C. Note 3. TA = 125°C, 1000 Hrs. Note 3. TA = 25°C 4.95 4.90 30 5.00 6.0 6.0 0.2 50 5.0 100 5.05 20 25 0.4 5.10 25 180 4.90 4.82 30 5.00 6.0 6.0 0.2 50 5.0 100 5.10 20 25 0.4 5.18 25 180 V mV mV mV/°C V µV mV mA Test Conditions Min Typ Max CS3844/CS3845 Min Typ Max Unit
3. These parameters, although guaranteed, are not 100% tested in production. *Adjust VCC above the start threshold before setting at 15 V.
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CS2844, CS3844, CS2845, CS3845
ELECTRICAL CHARACTERISTICS (continued) (25° TA 85° for CS2844/2845, 0° TA 70° for CS3844/CS3845.
VCC = 15 V*; RT = 10 k, CT = 3.3 nF for sawtooth mode; unless otherwise stated.) CS2842A/CS2843A Characteristic Error Amp Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth PSRR Output Sink Current Output Source Current VOUT High VOUT Low Current Sense Section Gain Maximum Input Signal PSRR Input Bias Current Delay to Output Output Section Output Low Level Output High Level Rise Time Fall Time Total Standby Current Startup Current Operating Supply Current VCC Zener Voltage PWM Section Maximum Duty Cycle Minimum Duty Cycle 46 48 50 0 46 48 50 0 % % VFB = VSENSE = 0 V, RT = 10 k, CT = 3.3 nF ICC = 25 mA 0.5 11 34 1.0 17 0.5 11 34 1.0 17 mA mA V ISINK = 20 mA ISINK = 200 mA ISOURCE = 20 mA ISOURCE = 200 mA TJ = 25°C, CL = 1.0 nF. Note 4. TJ = 25°C, CL = 1.0 nF. Note 4. 13 12 0.1 1.5 13.5 13.5 50 50 0.4 2.2 150 150 13 12 0.1 1.5 13.5 13.5 50 50 0.4 2.2 150 150 V V V V ns ns Notes 5 & 6. VCOMP = 5.0 V. Note 5. 12 VCC 25 V. Note 5. VSENSE = 0 TJ = 25°C. Note 4. 2.85 0.9 3.00 1.0 70 2.0 150 3.15 1.1 10 300 2.85 0.9 3.00 1.0 70 2.0 150 3.15 1.1 10 300 V/V V dB µA ns VCOMP = 2.5 V VFB = 0 2.0 VOUT 4.0 V Note 4. 12 VCC 25 V VFB = 2.7 V, VCOMP = 1.1 V VFB = 2.3 V, VCOMP = 5.0 V VFB = 2.3 V, RL = 15 k to GND VFB = 2.7 V, RL = 15 k to VREF 2.45 65 0.7 60 2.0 0.5 5.0 2.50 0.3 90 1.0 70 6.0 0.8 6.0 0.7 2.55 1.0 1.1 2.42 65 0.7 60 2.0 0.5 5.0 2.50 0.3 90 1.0 70 6.0 0.8 6.0 0.7 2.58 2.0 1.1 V µA dB MHz dB mA mA V V Test Conditions Min Typ Max CS3842A/CS3843A Min Typ Max Unit
4. These parameters, although guaranteed, are not 100% tested in production. 5. Parameters measured at trip point of latch with VFB = 0. 6. Gain defined as: A = VCOMP/VSENSE; 0 VSENSE 0.8 V. *Adjust VCC above the start threshold before setting at 15 V.
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CS2844, CS3844, CS2845, CS3845
ELECTRICAL CHARACTERISTICS (continued) (25° TA 85° for CS2844/2845, 0° TA 70° for CS3844/CS3845.
VCC = 15 V*; RT = 10 k, CT = 3.3 nF for sawtooth mode; unless otherwise stated.) CS2844 Characteristic Test Conditions Min Typ Max Min CS3844 Typ Max CS2845/CS3845 Min Typ Max Unit
Undervoltage Lockout Section Start Threshold Min. Operating Voltage After Turn On 15 9.0 16 10 17 11 14.5 8.5 16 10 17.5 11.5 7.8 7.0 8.4 7.6 9.0 8.2 V V
*Adjust VCC above the start threshold before setting at 15 V.
PACKAGE PIN DESCRIPTION
Package Pin Number DIP8 & SO8 1 2 3 4 5 6 7 8 SO14 1 3 5 7 9 8 10 11 12 14 2, 4, 6, 13 Symbol 3 4 5 6 11 10 12 13 14 15 1, 2, 7, 8, 9, 16 Symbol COMP VFB Sense OSC GND Pwr GND VOUT VCC Pwr VCC VREF NC Description Error amp output, used to compensate error amplifier. Error amp inverting input. Noninverting input to Current Sense Comparator. Oscillator timing network with capacitor to ground, resistor to VREF. Ground. Output driver ground. Output drive pin. Output driver positive supply. Positive power supply. Output of 5.0 V internal reference. No connection.
VREF RT 2N2222 4.7 k 100 k 1.0 k ERROR AMP ADJUST 4.7 k VFB 5.0 k Sense ADJUST Sense OSC COMP VREF 0.1 µF VCC VOUT GND 1.0 k 1.0 W 0.1 µF VOUT A VCC
GND CT
Figure 2. Test Circuit Open Loop Laboratory Test Fixture
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Others parts begin by cs
CS-1 CS-2 CS-3 CS-4 CS-5 CS-6 CS-7 CS-8 CS-9 CS-10 CS-11 CS-12 CS-13 CS-14 CS-15 CS-16
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