AT1366 ETC | Alldatasheet

Document overview

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  • PDF pages: 13

Technical content

Features

  • High efficiency (95%) possible
  • No Schottky Diode Required
  • 800mA Output Current at 5V input 3.3V output
  • Oscillation frequency 1.0MHz
  • Built-in ON/OFF Function
  • Low Dropout Operation: 100% Duty Cycle
  • Stand-by current max. 1µA
  • Input voltage: 2.5V ~5.5V

Applications

  • Power Supply for portable devices General Description The A T1366 prov ides com plete con trol f or a DC/DC converter opti mized for h igh-performance microprocessor appl ications. It i s operat ed on current mode arch itecture f or ex cellent li ne an d load transient response. 1MHz operation frequency is allowing the use of small surface mount inductor and capacitor. The in ternal s ynchronous s witch increases efficiency and eliminates the need for an external Schottky di ode. T he A T1366 i s a f amily of l ow-noise s ynchronous st ep-down D C/DC converters th at is ideall y s uited f or s ystems powered f rom a 1- cell Li-ion bat tery or f rom a 3-cell to 4-cell NiCd, NiMH, or alkaline battery. It can also be used to USB-Based power system. Block Diagram Aimtron reserves the right without notice to change this circuitry and specifications. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Pin Configuration

Ordering Information

Part number Package Marking AT1366X SOT-25 AT1366X_GRE SOT-25, Green , Date Code with one bottom line : Date Code Pin Description Symbol Pin No. Descript RUN 1 ON/OFF Control GND 2 Power ground SW 3 Switch Node Connection to Inductor VIN 4 Power Supply FB 5 Output Feedback Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Absolute Maximum Ratings Rated Value Parameter Condition Min. Max. Unit Power Supply Voltage — -0.3 +6.0 V RUN,FB -0.3 VIN V Input Pin Voltage SW -0.3 VIN+0.3 V P-Channel Switch Source Current (DC) — - 1000 mA N-Channel S witch Si nk C urrent (DC) — - 1000 mA Peak SW Sink and Source Current — - 1.5 A Thermal Resistance from Junction to Ambient θJA SOT25 - 165 0C/W Operating temperature TA — -35 +85 0C Storage temperature — -55 +150 0C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Recommended Operating Conditions (Ta=+250C) Values Parameter Symbol Min. Typ. Max. Unit Power supply voltage VIN 2.5 -- 5.5 Ｖ Operating temperature* TA -20 +25 +85 °C Operating junction temperature TJ - - +150 °C *Using X5R or X7R input capacitors. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller

Electrical Characteristics

(VIN = 3.6V,Ta =+25℃ , unless otherwise noted. ) Values Parameter Symbol Condition Min. Typ. Max. Unit Input Supply Range VIN 2.5 -- 5.5 V Quiescent Current* IS FB=0.8V, Iload=0A Active Mode -- 300 -- µA Current in standby mode IST RUN=0V, VIN=5.5V -- 0.5 1 µA Feedback Voltage VFB Ta =-20℃ to +85℃ 0.784 0.800 0.816 V Feedback Voltage line-regulation VFB-Line VCC=2.5V to 5.5V -- 0.1 0.5 % Feedback Variation with Temperature Ta =-20℃ to +85℃ -- 0.5 1.0 % Feedback current IFB -- -- ±200 nA Peak Inductor Current* IPK VIN=5V,VOUT=3.3V 1.10 1.25 1.50 A Maximum Output Current* IO VIN=5V±5%, VOUT=3.3V, L=4.7µH - - 800 mA fosc1 FB=0.8V 0.8 1.0 1.2 MHz Oscillator Frequency fosc2 FB=0V -- 200 -- KHz RDS(ON) o f P -Channel MOSFET RPFET ISW=600mA -- 0.4 0.5 Ω RDS(ON) of N-Channel MOSFET RNFET ISW=-600mA -- 0.35 0.45 Ω SW Leakage Current ILSW RUN=0V,SW=0V or 5V,VIN=5V -- ±0.1 ±1 µA RUN Threshold VRUN 0.3 1.0 1.5 V RUN leakage Current IRUN -- ±0.1 ±1 µA L tVVIIII ONOUTIN OOPK × ×−+=∆+= 2 Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Typical characteristics : (refer to Figure 2) Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Typical characteristics : Start-Up from Shutdown(VIN=3.6V) CH1:RUN CH2 :VOUT C H4:IL Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Typical characteristics (Continuted) VIN=5V,VOUT=3.3V CH2:VOUT CH4: IOUT ILOAD=0mA to 600mA ILOAD= 50mA to 600mA ILOAD= 100mA to 600mA ILOAD= 200mA to 600mA ILOAD= 50mA to 800mA ILOAD= 200mA to 800mA Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller

Application Information

In continuous mode, the source cur rent of the top MOSFET is square w ave of dut y cycle. The Primary function of the input capacitor is to provide a low impedance loop for the ed ges of pulsed current drawn by the AT1366. A load step at the output can induce ringing at the input VIN. This ringing can couple to the output and be mistaken as loop instability. The oscillation can be improved by add the capacitance of the input capacitor. A typical value is 4.7~22µF ceramic (X5R or X7R), POSCAP or Aluminum Polymer. These capacitors will provide good high frequency bypassing and the ir low ESR will reduce resistive losses for hig her ef ficiency. Th e input capacitor RM S current v aries with the input voltag e a nd the ou tput voltag e. Th e equ ation for the maximum RMS current in the input capacitor is: )1( IN O IN O OMAXRMS V V V VII −= The output capa citor d epends on the suitabl e ripple voltage. Low rip ple voltage corresponds to lower ef fective series resi stance ( ESR). The output ripple voltag e is determined by: OUT LOUT fCESRIV +∆≅∆ The output capacitor RMS ripple current is given by: IN OUTINOUT RMS VfL VVVI ×× −×= )( When choosing the inp ut and output ceramic capacitors, choos e the X5 R o r X 7R dielectric form ulations. These di electrics hav e the best t emperature and vol tage characteristics of all the ceramics for a given value and size. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Inductor Selection The inductor is chos en based on the d esired ripple curr ent. Large v alue inductors lower ripple current and small value inductors result in h igher ripple current. Always consider the losses associated with the DCR and its ef fect on the tot al converter efficiency when sele cting an inductor . The inductor is selected to lim it the ripple current to some predetermined value, typically 20~40% of the full load current at the maximum input voltage. The formula of inductance value is as below: )(4.0~2.0 MAXOUTL II ×=∆  −∆×= IN OUT L OUT V V If VL 1 Adjustable Output Voltage The AT1366 appears a 0.8V reference voltage at FB pin. The output voltage is set by a resistive divider which is according to the following formula: 21(8.0 R RVVOUT +×= *R1=150KΩ for stability consideration. The Dissipation The power loss is given by: INsfrOINNONDSOPONDSOLOSS VIttIVDRIDRIP ×++××+−××+××= −− )()1()( LOSSJAAMAXJ PTT ×+= θ)( Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21 1 0

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Inductors Surface Mount Inductance(µH) Manufacturer/Part No. Manufacturer Website

3.3 Sumida CDRH4D28-3R3

4.7 Sumida CDRH5D18-4R7

www.sumida.com 3.3 Mitsumi C3-K1.8L-3R3 Mitsumi C4-K1.8L-3R3 www.mitsumi.co.jp

3.3 ABC SH40283R3YSB

4.7 ABC SH40284R7YSB

www.atec-group.com Capacitors Surface Mount Capacitance(µF) Manufacturer/Part No. Manufacturer Website 22 TDK C3216X5R0J226M www.tdk.com 47 TDK C3225X5R0J46M www.tdk.com 10 GRM42-6X5R 106K6.3 www.murata.com 4.7 TAIYO JMK212BJ475MG www.t-yuden.com Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21 1 1

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller PC Board Layout 1. The most critical aspe ct of the layout is the placement of the input capa citor C1. It must be placed as close as possible to the AT1366 to reduce th e input ripple voltage. 2. Power loops on the inpu t and output of th e converter should b e laid out with the shortest and widest traces possible. The longer and narrower the t race, the higher resistance and inductan ce it w ill have. The leng th of t races in seri es with the capacitors i ncreases i ts ES R and ES L and re duces t heir e ffectiveness at hi gh frequency. 3. The FB pin should connect to feedback resistors directly. And the route should be away from the noise source, such as inductor of SW line. 4. Grounding all components at the same poi nt may effectively reduce the occurrence of loop. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21 1 2

Preliminary Product Information 1MHz,800mA Synchronous Buck Controller Package Outline :SOT-25 INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX NOTES A 0.035 0.057 0.90 1.45 - A1 0.000 0.006 0.00 0.15 - A2 0.035 0.051 0.90 1.30 - b 0.010 0.020 0.25 0.50 - C 0.003 0.008 0.08 0.20 - D 0.110 0.122 2.80 3.10 - E 0.102 0.118 2.60 3.00 - E1 0.059 0.069 1.50 1.75 - L 0.014 0.022 0.35 0.55 e 0.037ref 0.95ref e1 0.075ref 1.90ref r 00 100 00 100 - Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 E mail: service@aimtron.com.tw 0 5/04/21 1 3