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Details, datasheet, quote on part number:ZXSC100N8
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Datasheet text preview:
ZXSC100
SINGLE CELL DC-DC CONVERTER SOLUTION
DESCRIPTION The ZXSC100 series is designed for DC-DC applications where step-up voltage conversion from very low input voltages is required. These applications mainly operate from single nickel cadmium or nickel metal hydride battery cells. The ZXSC100 devices are non-synchronous PFM, DC-DC controller ICs which drive an external transistor. Zetex SuperSOT4TM switching transistors, with saturation resistance as low as 13m, are recommended as the external switching element. These bipolar transistors are the best switching devices available for this type of DC-DC conversion, enabling high efficiency conversion with input voltages down to below 1 volt. The circuit can start up under full load with regulation maintained down to an input voltage of only 0.926 volts. The solution configuration ensures optimum FEATURES · · SuperSOT4TM switching transistor ZXT14N20DX:VCE(sat) 45mV max @ 1A load Efficiency maintained over a wide range of input voltages and load currents 82% efficiency @ VBATT=1V Startup under full load Minimum operating input voltage VBATT=0.926V Adjustable output voltage down to VBATT Quiescent current typically 150µA referred to input voltage MSOP8 Package SO8 Package
U1
EM BAS RE
VC C
efficiency over a wider range of load currents, several circuit configurations are possible with power dissipation up to 2W. The step up output voltage is easily programmed with external resistors, the non-synchronous architecture and SuperSOT4TM device enabling an output voltage down to the input voltage level. For best performance the ZXSC100 quiescent current is a small 150µA ensuring minimum battery drain in no load conditions. For the best in space saving the ZXSC100 is offered in the MSOP8 package, however the devices are also available in SO8 packaging for applications where space saving is not so critical. The IC and discrete combination offers the ultimate cost vs performance solution for single cell DC-DC conversion.
APPLICATIONS(continued) · · · · · Hand Held Instruments Portable Medical Equipment Solar Powered Equipment LED Flashlight LED Backlight
· · · · · ·
TYPICAL APPLICATION CIRCUIT
VBATT
L1
D1
ZHCS2000
3.3V/0.1A
R1 Q1
ZXT14N20DX VDRIVE ISENSE FB GND
R3 C3 C2
APPLICATIONS · · · · · · · · · Cordless Telephones MP3 Players PDA Pagers Battery Backup Supplies Electronic toothbrush GPS Receivers Digital Camera Palmtop Computers
ZXSC100
C1
R2
R4
ISSUE 2 - MAY 2003 1
SEMICONDUCTORS
ZXSC100
ABSOLUTE MAXIMUM RATING
Supply Voltage Maximum Voltage Other Pins Power Dissipation MSOP8 SO8 0.3 to 3.5V 0.3 to VCC+0.3V 500mW 780mW Operating Temperature Storage Temperature Junction Temperature 0 to 70°C -55 to 125°C 150°C
ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated) VCC=1.2V, TA = 25°C
Symbol ICC IDRIVE VDRIVE VFB VISENSE TCVISENSE VDREF TCVDREF VCC(SRT) VCC(min) VCC(hys) IFB IISENSE VO(min) VO(max) Parameter Quiescent current Base drive current VDRIVE o/p voltage Feedback voltage Output current reference voltage ISENSE voltage temp co. Drive current reference voltage VDREF temp co. Startup voltage Minimum operating input voltage Supply start up to shutdown hysteresis Feedback input current ISENSE input current Minimum Output Voltage Maximum Output Voltage ZXT14N20DX as pass element1 VISENSE = 0V 3 VCC 20 Any output load 1.01 0.926 Measured with respect to VCC 20 Conditions Not switching VRE = VCC VRE = VCC, IDRIVE = 5mA 5 VCC - 0.17 708 12 730 17.5 0.4 30 1 1.06 0.98 80 100 4 200 5.5 1.1 1 40 752 24 Min Typ 150 Max 200 10 Units µA mA V mV mV %/°C mV %/°C V V mV nA µA V V
1
Depends on breakdown voltage of pass device. See ZXT14N20DX data sheet
ISSUE 2 - MAY 2003
SEMICONDUCTORS
2
ZXSC100
ELECTRICAL CHARACTERISTICS: AC PARAMETERS2 TEST CONDITIONS (Unless otherwise stated) ) VCC=1.2V, TA = 25°C
Symbol TOFF FOSC
2 3
Parameter Discharge Pulse Width Recommended operating frequency3
Conditions
Min 1.7 3
Typ 4
Max
Units µs kHz
200
These parameters guaranteed by Design Operating frequency is application circuit dependant. See applications section
ZXT14N20DX
For the circuits described in the applications section, Zetex ZXT14N20DX is the recommended pass transistor. The following indicates outline data for the ZXT, more detailed information can be found in the Zetex SuperSOT4 data book or at www.zetex.com
ELECTRICAL CHARACTERISTICS (at TA = 25°C unless otherwise stated).
PARAMETER Collector-Emitter Breakdown Voltage Collector-Emitter Saturation Voltage SYMBOL V(BR)CEO VCE(sat) MIN. 20 TYP. 30 4.5 30 75 6 45 95 MAX. UNIT V mV mV mV CONDITIONS. IC=10mA* IC=0.1A, IB=10mA* IC=1A, IB=10mA* IC=4A, IB=40mA*
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle 2%
ZHCS2000
For the circuits described in the applications section Zetex ZHCS2000 is the recommended Schottky diode. The following indicates outline data for the ZHCS, more detailed information is available at www.zetex.com
ELECTRICAL CHARACTERISTICS (at Tamb = 25°C unless otherwise stated).
PARAMETER Forward Voltage Reverse Current Reverse Recovery Time SYMBOL VF IR trr 5.5 MIN. TYP. MAX. 385 500 300 UNIT mV mV µA ns CONDITIONS. IF=1A IF=2A VR=30V Switched from IF = 500mA to IR = 500mA. Measured at IR=50mA
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle 2%
ISSUE 2 - MAY 2003 3
SEMICONDUCTORS
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