AMS1070 AMS | Alldatasheet

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Technical content

DESCRIPTION

The AMS1070 is a monolithic synch ronous buck regulator. The device integra tes 100 mΩ MOSFETS that provide 3A of continuous lo ad current over a wide operating inp ut voltage of 4.75V to 23V. Current mode con trol provides fast transi ent response and c ycle-by-cycle current limit. An adjustable soft-start prevents inrush current at turn-on and in shut down mode, the supply current drops below 1µA. This device, available in an 8-pin ESOP8 package, provides a very com pact system solution with minimal reliance on external components.

FEATURES

  • 3A Continuous Output Current 4A Peak Output Current
  • Wide 4.75V to 23V Operating Input Range
  • Integrated 100mΩ Power MOSFET Switches
  • Output Adjustable from 0.925V to 20V
  • Up to 95% Efficiency
  • Programm able Soft-Start
  • Stable with Low ESR Ceramic Output Capacitors
  • Fixed 380KHz Frequency
  • Cycle-by-Cycle Over Current Protection
  • Input Under Voltage Lockout
  • Thermally Enhanced 8-Pin ESOP8 Package

APPLICATIONS

  • Distributed Power Systems
  • Networking Systems
  • Notebook Computers TYPICAL APPLICATION INPUT 4.75V to 23V OUTPUT 3.3V 3.9nF 10nF AMS1070 BSIN FB SW SS GND COMP EN 10uH (4A) 10uF/25V CERAMIC X 2 100K 26.1K 22uF/6.3V CERAMIC X 2 10K 6.8K 0.1uF AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com

(1) Supply Voltage V IN Switch Voltage V SW IN + 0.3V Boost Voltage V BS SW – 0.3V to V SW + 6V Recommended Operating Conditions (2) Input Voltage V IN Output Voltage V OUT Notes: 1) Exceeding these ratings may damage the device. 2) The device is not guaranteed to function outside of its operating conditions.

ELECTRICAL CHARACTERISTICS

V IN = 12V, T A = +25°C, unless otherwise noted. Parameter Symbol Condition Min Typ Max Units Shutdown Supply Current V EN = 0V 1.0 3.0 µA Supply Current V EN = 2.0V, V FB = 1.0V 1.3 1.5 mA Feedback Voltage V FB 4.75V ≤ V IN ≤ 23V 0.900 0.925 0.950 V Feedback Overvoltage Threshold 1.1 V Error Amplifier Voltage Gain (3) A EA

400 V/V

Error Amplifier Transconductance G EA C = ±10µA 820 µA/V High-Side Switch On-Resistance (3) R DS(ON)1 100 m Ω Low-Side Switch On-Resistance (3) R DS(ON)2 100 m Ω High-Side Switch Leakage Current V EN = 0V, V SW = 0V 0 10 µA Upper Switch Current Limit Minimum Duty Cycle 4.0 5.8 A Lower Switch Current Limit From Drain to Source 0.9 A COMP to Current Sense Transconductance G CS

5.2 A/V

380 KHz

Short Circuit Oscillation Frequency F osc2 V FB = 0V 110 KHz Maximum Duty Cycle D MAX V FB = 1.0V 90 % Minimum On Time (3) T ON 2 10 ns EN Shutdown Threshold Voltage V EN Rising 1.1 1.5 2.0 V EN Shutdown Threshold Voltage Hysterisis 220 mV AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com

(continued) V IN = 12V, T A = +25°C, unless otherwise noted. Parameter Symbol Condition Min Typ Max Units EN Lockout Threshold Voltage 2.2 2.5 2.7 V EN Lockout Hysterisis 210 mV Input Under Voltage Lockout Threshold V IN Rising 4.3 V Input Under Voltage Lockout Threshold Hysteresis 210 mV Soft-Start Current V SS = 0V 6 µA Soft-Start Period C SS = 0.1µF 15 ms Thermal Shutdown (3) 160 °C Note: 3) Guaranteed by design, not tested. AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com

Pin # Name Description 1 BS High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET switch. Connect a 0.01µF or greater capacitor from SW to BS to power the high side switch. 2 IN Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN with a 4.75V to 23V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input to the IC. 3 SW Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to power the high-side switch. 4 GND Ground (Connect the exposed pad to Pin 4). 5 FB Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage divider connected to it from the output voltage. The feedback threshold is 0.925V.

6 COMP

Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC network from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. 7 EN Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator; low to turn it off. Attach to IN with a 100kΩ pull up resistor for automatic startup. 8 SS Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set the soft-start period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the soft-start feature, leave SS unconnected. AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com

Advanced Monolithic Systems http://www.ams-semitech.com

TYPICAL APPLICATION CIRCUIT INPUT 4.75V to 23V OUTPUT 3.3V 3.9nF B130 (optional) 10nF AMS1070 BSIN FB SW SS GND COMP EN (optional) AMS1070 with 3.3V Output, 22uF/6.3V Ceramic Output Capacitor Recommended Resistance Values VOUT R1 R2 1.8V 9.53K 10K 2.5V 16.9K 10K 3.3V 26.1K 10K 5V 44.2K 10K 12V 121K 10K VOUT=0.925X(1+R1/R2) 10uF/25V CERAMIC X 2 22uF/6.3V CERAMIC X 2 10K 100K 0.1uF R3 6.8K 26.1K 10uH (4A) AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com

NOTE: 1) Control dimension is in inches. Dimension in bracket is millimeters. ESOP8 AMS1070 Advanced Monolithic Systems http://www.ams-semitech.com