Electronic Components Datasheet Search |
|
AS1322A-BTTT Datasheet(PDF) 7 Page - ams AG |
|
AS1322A-BTTT Datasheet(HTML) 7 Page - ams AG |
7 / 17 page www.austriamicrosystems.com Revision 1.07 7 - 17 AS1322 Data Sheet - Deta iled Description 8 Detailed Description The AS1322/AS1322B can operate from a single-cell input voltage (VIN) below 1V, and feature fixed frequency (1.2MHz) and current mode PWM control for exceptional line- and load-regulation. With low RDS(ON) and gate charge internal NMOS and PMOS switches, the devices maintain high-efficiency from light to heavy loads. Modern portable devices frequently spend extended time in low-power or standby modes, switching to high power- drain only when certain functions are enabled. The AS1322A and the AS1322B are ideal for portable devices since they maintain high-power conversion efficiency over a wide output power range, thus increasing battery life in these types of devices. In addition to high-efficiency at moderate and heavy loads, the AS1322A includes an automatic powersave mode that improves efficiency of the power converter at light loads. The powersave mode is initiated if the output load current falls below a factory programmed threshold (see Figure 3 on page 5). Note: The AS1322B does not support powersave mode and provides continuous operation at light loads, eliminating low-frequency VOUT ripple at the expense of light load efficiency. Figure 15. Block Diagram Low-Voltage Start-Up The AS1322 requires VIN of only 0.85V (typ) or higher to start up. The low-voltage start-up circuitry controls the internal NMOS switch up to a maximum peak inductor current of 850mA (typ), with 1.5ms (approx.) off-time during start-up, allowing the devices to start up into an output load. With a VOUT > 2.3V, the start-up circuitry is disabled and normal fixed-frequency PWM operation is initiated. In this mode, the AS1322 operates independent of VIN, allowing extended operating time as the battery can drop to several tenths of a volt without affecting output regulation. The limiting factor for the application is the ability of the battery to supply sufficient energy to the output. AS1322 + – Start Up OSC PWM Control A/B MUX Slope Compensator 1.2MHz Ramp Generator + – Powersave Operation Control – Shutdown Control PWM Comp Σ + – 1.23V Ref Sync Drive Control A B VOUT Good 2.3V gm Error Amp Shutdown Powersave 0.35 Ω 0.45 Ω R2 640k Ω 1% R1 1.02M Ω 1% CFF* COUT 4.7µF 3.3V Output CIN 1µF 1.5V Single Cell * Optional Current Sense RC 80k Ω CP2 2.5pF CC 150pF GND 2 SW 1 4 SHDNN 3 FB 6 VIN 5 VOUT L1 4.7µH |
Similar Part No. - AS1322A-BTTT |
|
Similar Description - AS1322A-BTTT |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |