DatasheetsPDF.com

A8697 Dataheets PDF



Part Number A8697
Manufacturers Allegro MicroSystems
Logo Allegro MicroSystems
Description Wide Input Voltage 4.0A Step Down Regulator
Datasheet A8697 DatasheetA8697 Datasheet (PDF)

A8697 Wide Input Voltage 4.0 A Step Down Regulator Features and Benefits ▪ 8 to 25 V input range ▪ Integrated DMOS switch ▪ Adjustable fixed off-time ▪ Adjustable output Package: 8-Lead SOIC with exposed thermal pad (suffix LJ) Description The A8697 is a constant off-time current mode step-down regulator with a wide input voltage range. Regulation voltage is set by external resistors, to output voltages as low as 0.8 V. The A8697 includes an integrated power DMOS switch to reduce the total sol.

  A8697   A8697


Document
A8697 Wide Input Voltage 4.0 A Step Down Regulator Features and Benefits ▪ 8 to 25 V input range ▪ Integrated DMOS switch ▪ Adjustable fixed off-time ▪ Adjustable output Package: 8-Lead SOIC with exposed thermal pad (suffix LJ) Description The A8697 is a constant off-time current mode step-down regulator with a wide input voltage range. Regulation voltage is set by external resistors, to output voltages as low as 0.8 V. The A8697 includes an integrated power DMOS switch to reduce the total solution footprint. It also features internal compensation, allowing users to design stable regulators with minimal design efforts. The off-time can be set with an external resistor, allowing flexibility in inductor selection. Additionally, the A8697 has a logic level enable pin which can shut the device down and put it into a low quiescent current mode for power sensitive applications. The A8697 is supplied in a low-profile 8-lead SOIC with exposed pad (package LJ). Applications include: ▪ Applications with 8 to 25 V input ▪ Consumer electronics, networking equipment ▪ 12 V lighter-powered applications (portable DVD, etc.) ▪ Point of Sale (POS) applications Approximate Scale 1:1 Typical Application CBOOT 0.01 μF VIN +12 V + CIN 47 μF 25 V BOOT VIN ENB LX A8697 TSET RTSET 51.1 k7 GND VBIAS FB Ratings: L: CDRH104R-3R8 COUT: EEUFM1V151 CIN: EEVFC1H470P L 3.8 μH D1 R1 2 k7 R2 6.14 k7 Circuit for 12 V step down to 1.06 V at 4 A VOUT 1.06 V/ 4.0 A + COUT 150 μF 56 mΩ Efficiency (%) Efficiency versus Load Current 90 80 VOUT = 2.5 V 70 VOUT = 1.8 V 60 VOUT = 1.06 V 50 40 30 20 10 0 0 1 2 3 4 Load Current (A) Efficiency curve for circuit at left A8697-DS, Rev. 3 A8697 Wide Input Voltage 4.0 A Step Down Regulator Absolute Maximum Ratings Characteristic Symbol Conditions Min. Typ. Max. Units VIN Supply Voltage VIN – – 25 V VBIAS Input Voltage VBIAS –0.3 – 7 V Switching Voltage VS –1 – – V ENB Input Voltage VENB –0.3 – 7 V Operating Ambient Temperature Range TA Range E –40 – 85 °C Junction Temperature TJ(max) – – 150 °C Storage Temperature TS –55 – 150 °C *Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current ratings, or a junction temperature, TJ, of 150°C. Package Thermal Characteristics* Package RθJA (°C/W) PCB LJ 35 4-layer * Additional information is available on the Allegro website. Ordering Information Use the following complete part numbers when ordering: Part Numbera Packingb A8697ELJTR-T 13 in. reel, 3000 pieces/reel aLeadframe plating 100% matte tin. bContact Allegro for additional packing options. Description LJ package, SOIC surface mount with exposed thermal pad Allegro MicroSystems, LLC 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A8697 Wide Input Voltage 4.0 A Step Down Regulator Functional Block Diagram BOOT VIN ENB μC TSET GND VBB UVLO TSD Boot Charge – + Switch Disable Switch PWM Control + I_Peak Clamp – I_Demand – Error COMP + VIN VIN LX L1 D1 VOUT ESR COUT FB Bias Supply VBIAS Soft Start Ramp Generation 0.8 V Allegro MicroSystems, LLC 3 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A8697 Wide Input Voltage 4.0 A Step Down Regulator ELECTRICAL CHARACTERISTICS1,2 at TA = 25°C, VIN = 8 to 25 V (unless noted otherwise) Characteristics Symbol Test Conditions Min. VENB = LOW, VIN = 12 V, VBIAS = 3.2 V, VFB = 1.5 V (not switching) – VIN Quiescent Current IVIN(Q) VENB = LOW, VIN = 12 V, VBIAS < 3 V, VFB = 1.5 V – VENB = HIGH – VBIAS Input Current IBIAS VBIAS = VOUT – Buck Switch On Resistance RDS(on) TA = 25°C, IOUT = 3 A – Fixed Off-Time Proportion Based on calculated value –15 Feedback Voltage VFB 0.784 Output Voltage Regulation VOUT IOUT = 0 mA to 3 A –3 Feedback Input Bias Current IFB –400 Soft Start Time tss 5 Buck Switch Current Limit ICL VFB > 0.4 V VFB < 0.4 V 4.8 – ENB Open Circuit Voltage VOC Output disabled 2.0 ENB Input Voltage Threshold VENB(0) LOW level input (Logic 0), output enabled – ENB Input Current IENB(0) VENB = 0 V –10 VIN Undervoltage Threshold VUVLO VIN rising 6.6 VIN Undervoltage Hysteresis VUVLO(hys) VIN falling 0.7 Thermal Shutdown Temperature TJTSD Temperature increasing – Thermal Shutdown Hysteresis TJTSD(hys) Recovery = TJTSD – TJTSD(hys) – 1Negative current is defined as coming out of (sourcing) the specified device pin. 2Specifications over the junction temperature range of 0ºC to 125ºC are assured by design and characterization. Typ. 1.0 4.1 – 3.8 180 – 0.8 – –100 10 6.2 2.7 – – – 6.9 – 165 15 Max. – – 100 5 – 15 0.816 3 100 15 7.2 – 7 1.0 –1 7..


A8530 A8697 B10011S


@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site.
(Privacy Policy & Contact)