UC3843Q , CURRENT-MODE PWM CONTROLLERFeaturesThe UCx84x family offers a variety of package• Optimized for Off-Line and DC-to-DC Converte ..
UC3843Q , CURRENT-MODE PWM CONTROLLER SLUS223E–APRIL 1997–REVISED JANUARY 20175 Device Comparison TableUVLOTURNON AT 16 V TURNON AT 8.4 ..
UC3843T ,HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERBLOCK DIAGRAM (toggle flip flop used only in UC3844T and UC3845T)7ViUVLO34V85VVREF5 S/RREFGROUND 5V ..
UC3843TD ,HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERELECTRICAL CHARACTERISTICS ( [note 1] Unless otherwise stated, these specifications apply for0 < T ..
UC3843TN ,HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERUC3842T UC3843TUC3844T UC3845T® HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER. TRIMMED OSCILLATOR FO ..
UC3844 ,SMPS ControllerUC3842/UC3843/UC3844/UC3845SMPS Controller
UN2112 ,Composite DeviceTransistors with built-in ResistorUNR211x Series (UN211x Series)Silicon PNP epitaxial planar typeUn ..
UN2113 ,Composite DeviceFeatures• Costs can be reduced through downsizing of the equipment andreduction of the number of pa ..
UN2114 ,Composite DeviceFeatures• Costs can be reduced through downsizing of the equipment andreduction of the number of pa ..
UN2115 ,Composite DeviceAbsolute Maximum Ratings T = 25°CaParameter Symbol Rating UnitCollector-base voltage (Emitter open ..
UN2115- ,Composite DeviceAbsolute Maximum Ratings T = 25°CaParameter Symbol Rating UnitCollector-base voltage (Emitter open ..
UN2116 ,Composite DeviceAbsolute Maximum Ratings T = 25°CaParameter Symbol Rating UnitCollector-base voltage (Emitter open ..
UC3843Q
CURRENT-MODE PWM CONTROLLER
VIN
VCC
VREF
RT/CT
GROUND
VFB
ISENSE
OUTPUT
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UC1842, UC2842, UC3842, UC1843, UC2843, UC3843
UC1844, UC2844, UC3844, UC1845, UC2845, UC3845SLUS223E –APRIL 1997–REVISED JANUARY
UCx84x Current-Mode PWM Controllers Features Optimized for Off-Line and DC-to-DC Converters Low Start-Up Current(<1 mA) Automatic Feedforward Compensation Pulse-by-Pulse Current Limiting Enhanced Load-Response Characteristics Undervoltage Lockout With Hysteresis Double-Pulse Suppression High-Current Totem-Pole Output Internally Trimmed Bandgap Reference Upto 500-kHz Operation Error Amplifier With Low Output Resistance
Applications Switching Regulatorsof Any Polarity Transformer-Coupled DC-DC Converters
DescriptionThe UCx84x series of control integrated circuits
provide the features that are necessaryto implement
off-line or DC-to-DC fixed-frequency current-mode
control schemes, witha minimum numberof external
components. The internally implemented circuits
include an undervoltage lockout (UVLO), featuringa
start-up currentof less than1 mA, anda precision
reference trimmed for accuracyat the error amplifier
input. Other internal circuits include logicto ensure
latched operation,a pulse-width modulation (PWM)
comparator that also provides current-limit control,
anda totem-pole output stage thatis designedto
sourceor sink high-peak current. The output stage,
suitable for driving N-channel MOSFETs,is low whenisin theoff state.
The UCx84x family offersa variety of package
options, temperature range options, choice
maximum duty cycle, and choiceof turnon and turnoff
thresholds and hysteresis ranges. Devices
higher turnonor turnoff hysteresis are ideal choices
for off-line power supplies, while the devices with
narrower hysteresis range are suited for DC-DC
applications. The UC184x devices are specified
operation from –55°Cto 125°C, the UC284x series
specified for operation from –40°Cto 85°C, and
UC384x seriesis specified for operation from 0°C
70°C.
Device Information(1)(1) Forall available packages, see the orderable addendum
the endofthe datasheet.
Simplified Application
