Fs2119a Synchronous Boost IC output 3.3V and fs2119b Synchronous Boost IC output 5V

summary
FS2119A High efficiency synchronization , PWM Boost DC / DC converter , Provide efficient solutions for medium power systems . The working frequency is 1.4MHz frequency . allow
Use micro , Thin inductors and ceramic capacitors . Light load automatic PWM/PFM Mode switching saves energy , Increase of efficiency .
PW5200A Can provide 2.5V and 5V Between the output voltage .
characteristic ：
l It's as efficient as 94%
l Turn off the current ： <1μA
l Load current ： the height is 500mA
l Input voltage ： FS2119A:1V to 4.4V,FS2119B:2V to 4.4V
l Output voltage ： 2.5V to 5V（ Schottky is 5V）
l Low on resistance RDS（On）, Internal switch ： 0.35Ω
l 1.4MHz Constant frequency switch
l Automatically PWM/PFM Mode switch
l Frivolous SOT-23-6L encapsulation
FS2119A The input voltage is 1V-4.4V Between , fit 1-2 Save dry battery or lithium battery input ,
FS2119B The input voltage is 2V-4.4V Between , fit 2 Save dry battery or lithium battery input .
FS2119A/FS2119B It is an efficient synchronization PWM Boost type DC/DC Converter solutions .FS2119A/FS2119B The working frequency is 1.4MHZ. Automatically when the load is light PWM/PFM Mode switch , Increase of efficiency . FS2119A/FS2119B Can provide 2.5V and 5V Output voltage between internal synchronous rectifier switches , It saves Schottky and improves efficiency .

FS2119A Of PCB Layout design suggestions - The basic chapter
A common problem with switching power supply is “ unstable ” Switching waveform . Sometimes , Obvious waveform jitter , Noise can be heard from the magnetic elements
The sound . If the problem is with the PCB （PCB） Layout related , It is difficult to determine the cause . EMC Also pay attention to （PCB） Layout , This is for
What is the correct layout in the early stage of switching power supply design PCB The crucial reason . Its importance cannot be overstated .
Schematic wiring
Placement of main components
Connect a bypass capacitor in parallel 0.1uF
SW node
FB Feedback resistance R1,R2
COUT capacitance
Easy to affect the output wiring
Recommended pad patterns for power components
GND Power ground PCB wiring
Inductor selection schematic wiring
• Good layout design optimizes power efficiency , Reduce thermal stress , most important of all , Minimize noise and interaction between wiring and components .
• To begin PCB Before the layout , A good practice is to highlight the schematic wiring of high current wiring , Flat core micro products Datasheet In a typical application circuit , special
Marked prominently for customer reference ： Black thick line .

Placement of main components
• Switching power supply circuit can be divided into power stage circuit and small signal control circuit . The power stage circuit consists of components that conduct large currents . Usually , These components should be placed first
(FS2119A chip , L1, CIN and COUT). Then, the small signal control circuit FB Place in a specific location in the layout . The high current wiring of inductance shall be short and wide , To minimize
PCB inductance , Resistance and voltage drop .
• CIN Need to approach FS2119A Of VIN Pin PIN6, It is not recommended to place on the back of the via . COUT When conditions are limited , It can be placed on the back of the through hole .
• Cout Need to approach FS2119A Of vout Pin PIN5.

Connect a bypass capacitor in parallel 0.1uF
• It is suggested that CIN and Cout Add one in parallel 0.1uF-1uF High frequency decoupling capacitor , use X5R or X7R Dielectric ceramic capacitors , Its ESL and ESR Very low . And placed in
FS2119A Of VIN and Vout Next to the pin . Post on Ping Xin micro website {DC-DC For non disconnector power supply PCB Layout design } Medium CHF Namely 0.1uF. In this paper, from the boost junction
The structure is introduced and explained .
• CIN And bypass capacitance 0.1uF Be close to VIN Pin ;
• Cout And bypass capacitance 0.1uF Be close to Vout Pin .