UNISONIC TECHNOLOGIES CO., LTD L8401 LINEAR INTEGRATED CIRCUIT FET BIAS CONTROLLER DESCRIPTION The UTC L8401 is designed to bias the MOSFETs that are commonly used in LNBs that can implies minimum external components requires. FEATURES * Can Bias up to 4 FETs * Drain Current Adjustable by Two External Resistors. * Two Sets of Drain Current can be Setted. ORDERING INFORMATION Ordering Number L8401G-R16-R Package SSOP-16 Packing Tape Reel MARKING www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd 1 of 5 QW-R123-018.B L8401 LINEAR INTEGRATED CIRCUIT PIN CONFIGURATION FUNCTIONAL DIAGRAM Fig.1 FUNCTIONAL DESCRIPTION The UTC L8401 includes one negative supply required for gate biasing from the single supply voltage, and all the other bias requirements for external FETs. A low current negative supply voltage includes an internal OSC and two 47nF external cap. The negative rail generator is common to all devices. This negative supply voltage used to drive the FET’s gate to obtain the required drain current because of he FET is a depletion mode transistor. There are for stages in the IC to baising the four external FETS. The drain voltage of the external FET FET1~4 is 2.2 volts set by the UTC L8401. The drain current of external FET is determined by the external resist RCAL1 or RCAL2. External resistor RCAL1 sets the drain current of FET1 and FET 2, and resistor RCAL2 sets the drain current of FET3 and FET4. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 5 QW-R123-018.B L8401 LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Supply Voltage VCC -0.6~8 V Supply Current ICC 100 mA Maximum Drain Current 15 mA Maximum CSUB Sink Current -500 uA Operating Temperature TOPR -40~80 °C Storage Temperature TSTG -50~150 °C Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. ELECTRICAL CHARACTERISTICS (VCC=3.3V, ID=10mA, RCAL1=8.2KΩ, RCAL2=8.2KΩ, TA=25°C, unless otherwise stated) PARAMETER SYMBOL TEST CONDITIONS Supply Voltage VCC Supply Current ICC No FET ISUB=0uA, VCC=6V Negative Voltage VSUB ISUB=-200uA Oscillator Freq. fO Drain Current ID Drain Current Change with VCC ∆IDV VCC=3.3~6V VD1/VD2(VD3/VD4) Drain Offset ∆IDC Current Drain Current Change with Temp. ∆IDT T=-40~80°C Drain Voltage VD ID=10mA Drain Voltage Change with VCC ∆VDV VCC=3.3~6V Drain Voltage Change ∆VDT T=-40~80°C Dynamic Gate Voltage Range VG Csub without loading Drain Output Noise Voltage Vdn With drain bypass capacitor=10nF Gate Output Noise Voltage VGN With gate bypass capacitor=10nF UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN TYP MAX 3.3 6 10 -3.0 -2.5 -1 -1 200 350 800 8 10 12 0.2 UNIT V mA V V KHz mA %/V 0.2 mA 1.8 -2.5 0.1 2 0.5 50 %/°C V %/V ppm 0.7 V 0.05 VPP 0.03 VPP 2.2 3 of 5 QW-R123-018.B L8401 LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 5 QW-R123-018.B L8401 LINEAR INTEGRATED CIRCUIT APPLICATIONS INFORMATION It is application circuit of UTC L8401 in figure 2, the bias circuits is stable fully in -40°C ~80°C. CNB and CSUB are used to generated the negative supply on pin CSUB (about -2.5V), which can be used to power other external circuits, but it is low load current is noticeable. C1 and C2 are used to suppress noise or RF interference in each stage of the IC or other external circuits in application circiut system. Value of C1 and C2 could be used in 1nF to 100nF as design dependent. RCAL1 and RCAL2 are used to set the drain current of FETs 1 & 2 and FETS 3 & 4. If the same drain current is required for all FETs on UTC L8401, then the pin RCAL1 and RCAL2 can be connected to GND through only one res of half normal value. There are full protection for external FETs on chip: The gate output voltage is limitted in -2.5V~0.7V in any conditions including powerup and powerdown transients; If the negative bias generator be shorted or overloaded, the drain supply to FETs is shut down to avoid damage to the FETs by excessive drain current. The fig.3 is typical applications of UTC L8401 in LNB. UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 5 QW-R123-018.B