nx2154 Microsemi Corporation, nx2154 Datasheet
nx2154
Related parts for nx2154
nx2154 Summary of contents
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... DESCRIPTION The NX2154/2154A controller synchronous Buck controller IC designed for step down con- verter applications optimized to convert bus volt- ages from 2V to 40V to outputs as low as 0.8V voltage. The NX2154/2154A operates at fixed 300kHz. The NX2154/2154A employs fixed loss-less current limiting by sensing the Rdson of synchronous MOSFET followed by hiccup feature ...
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... REF V CC (Static) Outputs not switching I C =3300pF F =300kHz CC LOAD S (Static) Outputs not switching I C =3300pF F =300kHz BST LOAD S _UVLO V Rising CC CC _Hyst V Falling CC CC NX2154/2154A Typical values refer Min TYP MAX Units 0 4 4.2 V 0.22 V ...
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... Ldrv going Low to Hdrv H) going High, 10%-10% R (Ldrv) I=200mA source R (Ldrv) I=200mA sink I (Ldrv) source I (Ldrv) sink TLdrv(Rise) TLdrv(Fall) Tdead going Low to Ldrv L) going High, 10% to 10% NX2154 NX2154A NX2154/2154A Min TYP MAX Units 3.4 mS 1.7 300 kHz 1 2000 umho ...
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... This pin is connected to the source of the high side MOSFET and provides 8 SW return path for the high side driver. Also SW senses the low side MOSFETS current, when the pin voltage is lower than 360mV for NX2154, 540mV for NX2154A, hiccup will be triggered. Rev.1.2 02/26/07 ...
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... BLOCK DIAGRAM VCC 1.25V Bias Generator 0.8V COMP 0.3V START 0.8V Digital ramp start Up FB COMP START GND Figure 2 - Simplified block diagram of the NX2154/NX2154A Rev.1.2 02/26/07 70%Vp FB UVLO POR START OC OSC 0.6V CLAMP 1.3V CLAMP Hiccup Logic NX2154/2154A Hiccup Logic OC BST HDRV SW Control Logic VCC PWM LDRV ...
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... Input voltage Output voltage OUT I - Output current OUT DV - Output voltage ripple RIPPLE F - Working frequency Inductor current ripple RIPPLE Design Example The following is typical application for NX2154, the schematic is figure 33V IN V =5V OUT F =300kHz S I =3A OUT DV <=50mV RIPPLE DV < ...
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... OUT ESR N 30m ...(7) 250mV crit 1000 F 250mV 0. OUT ...(8) I step The number of capacitors has to satisfied both ripple and transient requirement. Overall, we can choose N=1. NX2154/2154A is true. In that case, the L L crit step 2 OUT tran E tran crit I step ...
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... To achieve the same effect as voltage amplifier, the compensator of transconductance amplifier must satisfy this condition: R able if R ||R ||R >>1/gm can be met at the same time Vout Zin R3 C3 Figure 3 - Type III compensator using transconductance amplifier NX2154/2154A 1 ...(11 ...(12 ...(13) ...
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... 33V =9.9k Choose R 7. Calculate C double pole by equation (11). is shown 12.2nF Choose C 8. Calculate C half the switching frequency 106pF Choose C NX2154/2154A equal to 10k 2 10k 0.8V REF 1.91k 5V-0.8V REF =1.91k and ESR . ...
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... this case, input 2nF Choose C are chosen 6. Calculate C half the switching frequency 63pF Choose C 7. Calculate 1.2k Choose R NX2154/2154A V 10k 0.8V 2 REF 8k -V 1.8V-0.8V REF = and ESR and C with the crossover ...
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... ESR zero ESR 2 Gain 2 5.3kHz P 2.Set R equal OUT Choose R 3. Set crossover frequency at 1/10~ 1/5 of the swithing frequency, here F 4.Calculate R NX2154/2154A Vref C2 C1 has to satisfy ESR OUT OUT 1 2 15uH 1000uF 1.3kHz ...
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... MOSFETs to the overall converter efficiency. In this design example, two STM6920 are used. They have the following parameters: V and R selection. =7A,R =45m , DSON There are two factors causing the MOSFET power loss:conduction loss, switching loss. NX2154/2154A Fb Vref OUT IN ...(19) =5V, I =3A, using equation (19), OUT OUT ...
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... Over Current Limit Protection Over current Limit for step down converter is achieved by sensing current through the low side MOSFET. For NX2154, the current limit is decided by the R of the low side mosfet. When synchronous DSON FET is on, and the voltage on SW pin is below 360mV, the over current occurs ...
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... L2 1uH D1 MBR0530T1 1uF C4 Vcc BST 0.1uF 7 2 Comp Hdrv C2 C1 15nF 220pF Ldrv Fb C7 4.7nF Gnd 800 NX2154/2154A C5 Cin 1uF 2 x 16SP180M M1 IRF3706 L1 1uH Vout +1.8V,20A (1500uF,13mohm IRF3706 14 ...
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... LUXEDN III star LED, VIN=12V) Rev.1.2 02/26/07 +5V 78L05 D1 MBR0530T1 5 1 0.1uF Vcc BST 2 Hdrv IRF7341 10uH Ldrv Gnd 3 LM358 Figure 10 - NX2154 LED application 0.8 1 1.2 Figure 12 - Startup in NX2154 LED application NX2154/2154A Vin +9V to 33V 1uF 220uF Vout Co 1000uF,30mohm LUXEON III star LED 0.1ohm 15 ...
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... SOIC8 PACKAGE OUTLINE DIMENSIONS Rev.1.2 02/26/07 NX2154/2154A 16 ...
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... Rev.1.2 02/26/07 NX2154/2154A 17 ...