A8670EESTR-T

A8670EESTR-T Datasheet

A8670 Fixed Frequency, 2 A Synchronous Buck Regulator

Part	Datasheet
A8670EESTR-T	A8670EESTR-T (pdf)

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A8670 Fixed Frequency, 2 A Synchronous Buck Regulator With Fault Warnings and Power OK Discontinued Product This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available. Date of status change December 3, 2013 Recommended Substitutions: For existing customer transition, and for new customers or new applications, contact Allegro Sales. NOTE For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. A8670 Fixed Frequency, 2 A Synchronous Buck Regulator With Fault Warnings and Power OK • High efficiency integrated FETs optimized for lower duty cycle voltage conversion 180 mΩ high side, 40 mΩ low side • Adjustable output voltage, down to V • Extremely short minimum controllable on-time; example allows 12 V conversion to V at >1 MHz • Reference accuracy of ±1% throughout temperature range • and Power OK pins for operating and protection modes Normal operation VFB low or high Overcurrent UVLO Thermal warning prior to TSD Thermal shutdown TSD short protection Timing resistor open circuit protection Continued on the next Package 20-contact QFN with exposed thermal pad suffix ES Approximate size The A8670 is a synchronous buck converter capable of delivering up to 2 A. The A8670 utilizes valley current mode control, allowing very short on-times to be achieved. This makes it ideal for applications that require very low output voltages relative to the input voltage, combined with high switching frequencies. Valley current mode control inherently provides improved transient response over traditional switcher schemes, through the use of a voltage feedforward loop and frequency modulation during large signal load changes. The A8670 includes a comprehensive set of diagnostic flags, allowing the host platform to react to a myriad of different conditions. A fault output indicates when either the temperature is becoming unusually high, or a single point failure has occurred for example, the switching node LX shorted to ground, or the timing resistor going open-circuit. A Power OK POK output is also provided after a fixed delay, to indicate when the output voltage is within regulation. The A8670 is a rugged solution, offering protection against input undervoltages, Continued on the next • Servers • Point of load supplies • Network and telecom • Storage Typical Application Diagram VIN 12 V R1 k Ω C1 10 uF POK FAULT Vpull-up R2 20 kΩ R3 20 kΩ C5 10 nF C6 100 nF BOOT A8670 TON ILIM EN C2 10 nF L1 uH C3 10 uF FAULT SS BIAS FB COMP R4 12 k Ω AGND PGND

PDF Datasheet Preview

A8670 Fixed Frequency, 2 A Synchronous Buck Regulator

With Fault Warnings and Power OK

Discontinued Product

This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available.

Date of status change December 3, 2013

Recommended Substitutions:

For existing customer transition, and for new customers or new applications, contact Allegro Sales.

NOTE For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative.

A8670

Fixed Frequency, 2 A Synchronous Buck Regulator With Fault Warnings and Power OK
• High efficiency integrated FETs optimized for lower duty cycle voltage conversion 180 mΩ high side, 40 mΩ low side
• Adjustable output voltage, down to V
• Extremely short minimum controllable on-time;
example allows 12 V conversion to V at >1 MHz
• Reference accuracy of ±1% throughout temperature range
• and Power OK pins for operating and protection
modes Normal operation VFB low or high Overcurrent UVLO Thermal warning prior to TSD Thermal shutdown TSD short protection Timing resistor open circuit protection

Continued on the next

Package 20-contact QFN with exposed thermal pad suffix ES

Approximate size

The A8670 is a synchronous buck converter capable of delivering up to 2 A. The A8670 utilizes valley current mode control, allowing very short on-times to be achieved. This makes it ideal for applications that require very low output voltages relative to the input voltage, combined with high switching frequencies. Valley current mode control inherently provides improved transient response over traditional switcher schemes, through the use of a voltage feedforward loop and frequency modulation during large signal load changes.

The A8670 includes a comprehensive set of diagnostic flags, allowing the host platform to react to a myriad of different conditions. A fault output indicates when either the temperature is becoming unusually high, or a single point failure has occurred for example, the switching node LX shorted to ground, or the timing resistor going open-circuit. A Power OK POK output is also provided after a fixed delay, to indicate when the output voltage is within regulation. The A8670 is a rugged solution, offering protection against input undervoltages,

Continued on the next
• Servers
• Point of load supplies
• Network and telecom
• Storage

Typical Application Diagram

VIN 12 V

R1 k Ω

C1 10 uF

POK FAULT

Vpull-up

R2 20 kΩ

R3 20 kΩ

C5 10 nF

C6 100 nF

BOOT

A8670

TON ILIM EN

C2 10 nF

L1 uH

C3 10 uF

FAULT SS BIAS

FB COMP

R4 12 k Ω

AGND PGND

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Datasheet ID: A8670EESTR-T 516087