Semiconductor Components Industries LLC April Rev

Dana

Description

Niveau: Supérieur, Doctorat, Bac+8
? Semiconductor Components Industries, LLC, 2004 April, 2004 ? Rev. 5 1 Publication Order Number: UC3842B/D UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV High Performance Current Mode Controllers The UC3842B, UC3843B series are high performance fixed frequency current mode controllers. They are specifically designed for Off?Line and dc?to?dc converter applications offering the designer a cost?effective solution with minimal external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle?by?cycle current limiting, programmable output deadtime, and a latch for single pulse metering. These devices are available in an 8?pin dual?in?line and surface mount (SOIC?8) plastic package as well as the 14?pin plastic surface mount (SOIC?14). The SOIC?14 package has separate power and ground pins for the totem pole output stage. The UCX842B has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off?line converters. The UCX843B is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off). Features • Trimmed Oscillator for Precise Frequency Control • Oscillator Frequency Guaranteed at 250 kHz • Current Mode Operation to 500 kHz • Automatic Feed Forward Compensation • Latching PWM for Cycle?By?Cycle Current Limiting • Internally Trimmed Reference with Undervoltage Lockout • High Current Totem Pole Output • Undervoltage Lockout with Hysteresis • Low

• vosc ?


• voltage feedback


• error amp


• current sense


• pwm section


• oscillator frequency


• startup threshold


• output voltage


• sense input

Sujets

• Régulation

Informations

• Publié par: profil-zyak-2012
• Nombre de lectures: 13
• Langue: English

Extrait

UC3842B, UC3843B,
UC2842B, UC2843B,
NCV3843BV
High Performance
Current Mode Controllers
The UC3842B, UC3843B series are high performance fixed http://onsemi.com
frequency current mode controllers. They are specifically designed for
Off−Line and dc−to−dc converter applications offering the designer a
PDIP−8cost−effective solution with minimal external components. These
N SUFFIXintegrated circuits feature a trimmed oscillator for precise duty cycle
CASE 626
control, a temperature compensated reference, high gain error 8
amplifier, current sensing comparator, and a high current totem pole
1
output ideally suited for driving a power MOSFET.
Also included are protective features consisting of input and
SOIC−8reference undervoltage lockouts each with hysteresis, cycle−by−cycle
8 D1 SUFFIXcurrent limiting, programmable output deadtime, and a latch for single
CASE 751
pulse metering. 1
These devices are available in an 8−pin dual−in−line and surface
mount (SOIC−8) plastic package as well as the 14−pin plastic surface
mount (SOIC−14). The SOIC−14 package has separate power and SOIC−14
ground pins for the totem pole output stage. D SUFFIX14
CASE 751AThe UCX842B has UVLO thresholds of 16 V (on) and 10 V (off),
1
ideally suited for off−line converters. The UCX843B is tailored for
lower voltage applications having UVLO thresholds of 8.5 V (on) and
7.6 V (off). PIN CONNECTIONS
Features
Compensation 1 8 V• Trimmed Oscillator for Precise Frequency Control ref
2 7Voltage Feedback VCC• Oscillator Frequency Guaranteed at 250 kHz
3 6Current Sense Output• Current Mode Operation to 500 kHz 4 5R /C GNDT T
• Automatic Feed Forward Compensation
(Top View)
• Latching PWM for Cycle−By−Cycle Current Limiting
Compensation 1 14 V• Internally Trimmed Reference with Undervoltage Lockout ref
2 13NC NC• High Current Totem Pole Output
3 12Voltage Feedback VCC• Undervoltage Lockout with Hysteresis
4 11NC VC
• Low Startup and Operating Current 5 10Current Sense Output
• Pb−Free Packages are Available NC 6 9 GND
V 7(12) 7 8CC R /C Power GroundT T
VVref CC (Top View)5.0V
Undervoltage
Reference
Lockout8(14) R
V ORDERING INFORMATIONref VCR Undervoltage See detailed ordering and shipping information in the package
Lockout 7(11) dimensions section on page 16 of this data sheet.
R /C OutputT T
Oscillator
6(10)4(7) DEVICE MARKING INFORMATIONLatching
PowerVoltage PWM See general marking information in the device marking
GroundFeedback + section on page 17 of this data sheet.
-Input 5(8)
2(3) Error Current
Output Amplifier Sense
Compensation 3(5) Input
1(1)
GND 5(9)
Pin numbers in parenthesis are for the D suffix SOIC−14 package.
Figure 1. Simplified Block Diagram
 Semiconductor Components Industries, LLC, 2004 1 Publication Order Number:
April, 2004 − Rev. 5 UC3842B/DUC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
MAXIMUM RATINGS
Rating Symbol Value Unit
Bias and Driver Voltages (Zero Series Impedance, see also Total Device spec) V , V 30 VCC C
Total Power Supply and Zener Current (I + I ) 30 mACC Z
Output Current, Source or Sink (Note 1) I 1.0 AO
Output Energy (Capacitive Load per Cycle) W 5.0 J
Current Sense and Voltage Feedback Inputs V − 0.3 to + 5.5 Vin
Error Amp Output Sink Current I 10 mAO
Power Dissipation and Thermal Characteristics
D Suffix, Plastic Package, SOIC−14 Case 751A
Maximum Power Dissipation @ T = 25°C P 862 mWA D
Thermal Resistance, Junction−to−Air R 145 °C/WJA
D1 Suffix, Plastic Package, SOIC−8 Case 751 = 25°C P 702 mWA D R 178 °C/WJA
N Suffix, Plastic Package, Case 626
Maximum Power Dissipation @ T = 25°C P 1.25 WA D R 100 °C/WJA
Operating Junction Temperature T +150 °CJ
Operating Ambient T T °CA
UC3842B, UC3843B 0 to + 70
UC2842B, UC2843B − 25 to + 85
UC3842BV, UC3843BV, NCV3843BV −40 to +105
Storage Temperature Range T − 65 to +150 °Cstg
ELECTRICAL CHARACTERISTICS (V = 15 V [Note 2], R = 10 k, C = 3.3 nF. For typical values T = 25°C, for min/max valuesCC T T A
T is the operating ambient temperature range that applies [Note 3], unless otherwise noted.)A
UC284XB UC384XB, XBV
Characteristics Symbol Min Typ Max Min Typ Max Unit
REFERENCE SECTION
Reference Output Voltage (I = 1.0 mA, T = 25°C) V 4.95 5.0 5.05 4.9 5.0 5.1 VO J ref
Line Regulation (V = 12 V to 25 V) Reg − 2.0 20 − 2.0 20 mVCC line
Load Regulation (I = 1.0 mA to 20 mA) Reg − 3.0 25 − 3.0 25 mVO load
Temperature Stability T − 0.2 − − 0.2 − mV/°CS
Total Output Variation over Line, Load, and Temperature V 4.9 − 5.1 4.82 − 5.18 Vref
Output Noise Voltage (f = 10 Hz to 10 kHz, T = 25°C) V − 50 − − 50 − VJ n
Long Term Stability (T = 125°C for 1000 Hours) S − 5.0 − − 5.0 − mVA
Output Short Circuit Current I −30 −85 −180 −30 −85 −180 mASC
OSCILLATOR SECTION
Frequency f kHzOSC
T = 25°C 49 52 55 49 52 55J
T = T to T 48 − 56 48 − 56A low high
T = 25°C (R = 6.2 k, C = 1.0 nF) 225 250 275 225 250 275J T T
Frequency Change with Voltage (V = 12 V to 25 V) f /V − 0.2 1.0 − 0.2 1.0 %CC OSC
Frequency Change with Temperature, T = T to T f /T − 1.0 − − 0.5 − %A low high OSC
Oscillator Voltage Swing (Peak−to−Peak) V − 1.6 − − 1.6 − VOSC
Discharge Current (V = 2.0 V) I mAOSC dischg
T = 25°C 7.8 8.3 8.8 7.8 8.3 8.8J
T = T to T (UC284XB, UC384XB) 7.5 − 8.8 7.6 − 8.8A low high
T = T to T (UC384XBV) − − − 7.2 − 8.8A low high
1. Maximum Package power dissipation limits must be observed.
2. Adjust V above the Startup threshold before setting to 15 V.CC
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T = 0°C for UC3842B, UC3843B; −25°C for UC2842B, UC2843B; −40°C for UC3842BV, UC3843BVlow
T = +70°C for UC3842B, UC3843B; +85°C for UC2842B, UC2843B; +105°high
NCV3843BV: T = −40°C, T = +105°C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site andlow high
change control.
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2UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
ELECTRICAL CHARACTERISTICS (V = 15 V [Note 4], R = 10 k, C = 3.3 nF. For typical values T = 25°C, for min/max valuesCC T T A
T is the operating ambient temperature range that applies [Note 5], unless otherwise noted.)A
UC284XB UC384XB, XBV
Characteristics Symbol Min Typ Max Min Typ Max Unit
ERROR AMPLIFIER SECTION
Voltage Feedback Input (V = 2.5 V) V 2.45 2.5 2.55 2.42 2.5 2.58 VO FB
Input Bias Current (V = 5.0 V) I − − 0.1 −1.0 − − 0.1 − 2.0 AFB IB
Open Loop Voltage Gain (V = 2.0 V to 4.0 V) A 65 90 − 65 90 − dBO VOL
Unity Gain Bandwidth (T = 25°C) BW 0.7 1.0 − 0.7 1.0 − MHzJ
Power Supply Rejection Ratio (V = 12 V to 25 V) PSRR 60 70 − 60 70 − dBCC
Output Current mA
Sink (V = 1.1 V, V = 2.7 V) I 2.0 12 − 2.0 12 −O FB Sink
Source (V = 5.0 V, V = 2.3 V) I − 0.5 −1.0 − − 0.5 −1.0 −O FB Source
Output Voltage Swing V
High State (R = 15 k to ground, V = 2.3 V) V 5.0 6.2 − 5.0 6.2 −L FB OH
Low State (R = 15 k to V , V = 2.7 V) VL ref FB OL
(UC284XB, UC384XB) − 0.8 1.1 − 0.8 1.1
(UC384XBV) − − − − 0.8 1.2
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 6 & 7) A V/VV
(UC284XB, UC384XB) 2.85 3.0 3.15 2.85 3.0 3.15
(UC384XBV) − − − 2.85 3.0 3.25
Maximum Current Sense Input Threshold (Note 6) V Vth 0.9 1.0 1.1 0.9 1.0 1.1
(UC384XBV) − − − 0.85 1.0 1.1
Power Supply Rejection Ratio (V = 12 V to 25 V, Note 6) PSRR − 70 − − 70 − dBCC
Input Bias Current I − − 2.0 −10 − − 2.0 −10 AIB
Propagation Delay (Current Sense Input to Output) t − 150 300 − 150 300 nsPLH(In/Out)
OUTPUT SECTION
Output Voltage V
Low State (I = 20 mA) V − 0.1 0.4 − 0.1 0.4Sink OL
(I = 200 mA) (UC284XB, UC384XB) − 1.6 2.2 − 1.6 2.2Sink
(UC384XBV) − − − − 1.6 2.3
High State (I = 20 mA) V 13 13.5 − 13 13.5 −Source OH − − − 12.9 13.5 −
(I = 200 mA) 12 13.4 − 12 13.4 −Source
Output Voltage with UVLO Activated (V = 6.0 V, I = 1.0 mA) V − 0.1 1.1 − 0.1 1.1 VCC Sink OL(UVLO)
Output Voltage Rise Time (C = 1.0 nF, T = 25°C) t − 50 150 − 50 150 nsL J roltage Fall Time (C, T = 25°C) t − 50 150 − 50 150 nsL J f
UNDERVOLTAGE LOCKOUT SECTION
Startup Threshold (V ) V VCC th
UCX842B, BV 15 16 17 14.5 16 17.5
UCX843B, BV 7.8 8.4 9.0 7.8 8.4 9.0
Minimum Operating Voltage After Turn−On (V ) V VCC CC(min)
UCX842B, BV 9.0 10 11 8.5 10 11.5
UCX843B, BV