Document
Green-Mode PWM Controller 300mA Driving Capability
ST6850
DESCRIPTION The ST6850 is the current mode PWM controller with green-mode power-saving operation which can meet the low standby-power needs for low power SMPS. This greenmode function enables the power supply to easily meet even the strictest power conservation requirements. The small package provides the high efficiency / low cost solution for SMPS power applications. ST6850 is processed by BiCMOS fabrication, that enables reducing the start-up current and the operating current. ST6850 is available by SOT-23-6L / DIP-8P packages.
PIN CONFIGURATION SOT-23-6L
DIP-8P
APPLICATIONS z AC / DC Switching Power Adaptor z Battery Charger z PC 5V Standby Power z Open-Frame Switching Power Supply
FEATURE z z z z z z z z z z z High-Voltage BiCMOS Process Very Low Startup Current( <25u ) Under Voltage Lockout( UVLO ) Current Mode Control Current Limiting Programmable Switching Frequency Intermal Slope Compensation Green-Mode Control for Power Saving Non-audible-noise Green Mode Control 300mA Driving Capability OVP (Over Voltage Protection) on Vcc Pin
PART MARKING SOT-23-6L
DIP-8P
YYWW
STANSON TECHNOLOGY
120 Bentley Square, Mountain View, Ca 94040 USA TEL: (650) 9389294 FAX: (650) 9389295
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Green-Mode PWM Controller 300mA Driving Capability
ST6850
TYPICAL APPLCTUON CIRCUIT ( High Efficiency SMPS )
ST6850
PIN DESCRIPTION
ST6850D8T Pin Symbol 1 OUT 2 VCC 3 NC 4 CS 5 6 7 RT NC COMP Descripton Gate driver output to drive the external MOSFET Supply Voltage Unconnected pin Current sense. This pin senses the voltage across a resistor, to control PWM output. This pin also provides current amplitude information for current-mode control. This pin is used to charge an internal capacitor, to determine the switching frequency. Unconnected pin Voltage feedback. The pin provides the output voltage regulation signal. It provides feedback to the internal PWM comparator, so that the PWM comparator can control the duty cycle. Grond
8
GND
STANSON TECHNOLOGY
120 Bentley Square, Mountain View, Ca 94040 USA TEL: (650) 9389294 FAX: (650) 9389295
Green-Mode PWM Controller 300mA Driving Capability
ST6850
SP6850S26R Pin Symbol Description 1 GND Ground 2 COMP Voltage feedback. The pin provides the output voltage regulation signal.. It provides feedback to the internal PWM comparator, so that the PWM comparator can control the duty cycle. 3 RT This pin is used to charge an internal capacitor, to determine the switching frequency. 4 CS Current sense. This pin senses the voltage across a resistor, to control PWM output. This pin also provides current amplitude information for current-mode control. 6 VCC Supply Voltage 7 OUT Gate driver output to drive the external MOSFET
STANSON TECHNOLOGY
120 Bentley Square, Mountain View, Ca 94040 USA TEL: (650) 9389294 FAX: (650) 9389295
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Green-Mode PWM Controller 300mA Driving Capability BLOCK DIAGRAM
ST6850
ORDERING INFORMATION
Part Number ST6850D8TG ST6850S26RG ST6850D8T : Tube; Pb – Free ST6850S26R: Tape Reel; Pb - Free Package DIP-8P SOT-23-6L Part Marking ST6850 805YW
STANSON TECHNOLOGY
120 Bentley Square, Mountain View, Ca 94040 USA TEL: (650) 9389294 FAX: (650) 9389295 Page 4
Green-Mode PWM Controller 300mA Driving Capability ABSOULTE MAXIMUN RATINGS ( Ta=25
ST6850
, unless otherwise specified.)
The following ratings designate persistent limits beyond which damage to the device may occur. Symbol Vcc Ccomp/ Rt/ Cs Pd Pj Tstg Tlead Parameter DC Supply Vlotage SYNC Power Dissipation @ Ta=85 * Operating Junction Temperature Range Storage Temperature Range Lead Soldering Temperaature for 5 sec Value 40 -3~7 0.3 150 150 Unit V V W
SOT-23-6L 220 DIP-8P 260 SOT-23-6L 95 Thermal Resistance Junction-Case(*) R jc /W DIP-8P 210 (*)The power dissipation and thermal resistance are evaluated under copper board mounted with free air conditions.
STANSON TECHNOLOGY
120 Bentley Square, Mountain View, Ca 94040 USA TEL: (650) 9389294 FAX: (650) 9389295
Page 5
Green-Mode PWM Controller 300mA Driving Capability ELECTRICAL CHARACTERISTICS (Ta=25
Symbol Parameter Supply Voltage ( Vcc Pin ) Istt Startup Current Iop Operating Current UVLO(off) Min. Operatinf Voltage UVLO(on) Start Threshold Voltage Voltage Feedback ( Comp Pin ) Isc Short Circuit Current Vop Vth(gm) Open Loop Voltage Green Mode Threshold VCOMP
ST6850
, Vcc=15V, unless otherwise specified.)
Coneitions Min. Typ. Max. Unit 8 2 9.0 15.0 16.0 2.2 5.0 2.35 25 4 17.0 3.0 uA mA V V mA V V
Vcomp=3V
10.0 11.0
Oscillator ( RT Pin ) Fosc Frequency Fosc(gm) Green Mode Frequency Frequency Variation versus Temp Deviation Fdv Frequency Variation versus Vcc Deviation Current Sensing ( CS Pin ) Vcs(off) Zcs Maximum Input Vlotage Input impedance Fdt
Rt=100K Fs=65.0KHz (-40 (Vcc=11V ~ 25V)
60.0
65.0 70.0 KHz 20 KHz 3 1 % %
0.8
0.85 50 150
0.9
V K nS
Tpd Delay to Output Gate Driver Output ( OUT pin ) VOL Output Low level VOH Tr Tf Output High Level Rising Time Falling Time
.