MP9942

Part: MP9942GJ — Monolithic Power Systems (MPS)

Type: Synchronous Step-Down (Buck) Converter with Power Good

Description: 4–36 V input, 2 A synchronous step-down converter with integrated 90 mΩ/55 mΩ MOSFETs, 410 kHz switching frequency, and a power-good output, in an 8-pin TSOT23 package.

Operating Conditions:

• Supply voltage: 4–36 V (continuous)
• Operating junction temperature: -40 to +125 °C
• Output voltage: 0.8 V to VIN×DMAX
• Sync clock range: 200 kHz to 2.2 MHz

Absolute Maximum Ratings:

• Max supply voltage (VIN): 40 V
• VSW: -0.3 V to 41 V
• VBS: VSW + 6 V
• All other pins: -0.3 V to 6 V
• Continuous power dissipation (TA = +25 °C, TSOT23-8): 1.25 W
• Max junction temperature: 150 °C
• Storage temperature: -65 to 150 °C
• Lead temperature: 260 °C

Key Specs:

• Feedback voltage: 780 / 792 / 804 mV (min/typ/max), VIN = 12 V, TJ = +25 °C
• Quiescent current: 0.5 mA typ, 0.7 mA max (VEN = 2 V, VFB = 1 V); shutdown current 8 μA max (VEN = 0 V)
• High-side/low-side RDS(ON): 90 mΩ typ (155 mΩ max) / 55 mΩ typ (105 mΩ max)
• Current limit: 3 / 4.2 / 5.5 A (min/typ/max), under 40% duty cycle
• Switching frequency: 320 / 410 / 500 kHz (VFB = 750 mV)
• Maximum duty cycle: 92% min, 95% typ (VFB = 750 mV, 410 kHz)
• Minimum on-time: 70 ns typ
• VIN UVLO: 3.5 V rising typ, 3.3 V falling typ
• Soft-start time: 1.45 ms typ (VOUT 10% to 90%)
• Thermal shutdown: 170 °C typ, 30 °C hysteresis
• Thermal resistance θJA: 100 °C/W (TSOT23-8, JESD51-7 4-layer PCB)

Features:

• Wide 4–36 V continuous input range
• High-efficiency synchronous operation with internal power-save mode (AAM)
• Synchronizes to an external clock from 200 kHz to 2.2 MHz
• High duty cycle for automotive cold-crank
• Internal soft-start
• Power Good indicator
• Over-current protection with hiccup
• Thermal shutdown
• Output adjustable from 0.8 V

Applications:

• Automotive
• Industrial control systems
• Distributed power systems

Package:

• TSOT23-8 (8-pin)

• Wide 4V to 36V Continuous Operating Input Range
• 90m Ω /55m Ω Low RDS(ON) Internal Power MOSFETs
• High-Efficiency Synchronous Mode Operation
• 410kHz Switching Frequency
• Synchronizes from 200kHz to 2.2MHz External Clock
• High Duty Cycle for Automotive Cold-crank
• Internal Soft-Start
• Internal Power-Save Mode
• Power Good Indicator
• Over-Current Protection with Hiccup
• Thermal Shutdown
• Available in an 8-pin TSOT-23 package
• Output Adjustable from 0.8V

• Automotive
• Industrial Control System
• Distributed Power Systems

All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. 'MPS' and 'The Future of Analog IC Technology' are Registered Trademarks of Monolithic Power Systems, Inc.

VIN = 12V, TJ = +25°C, unless otherwise noted.

Recommended Operating Conditions (4) Continuous Supply Voltage VIN ........... 4V to 36V Output Voltage VOUT .................. 0.8V to V IN *DMAX Operating Junction Temp. (TJ). -40°C to +125°C

Thermal Resistance (5) θ JA θ JC TSOT23-8 .............................. 100 ..... 55 ... °C/W

• 1. Absolute maximum ratings are rated under room temperature unless otherwise noted. Exceeding these ratings may damage the device.
• 1. About the details of EN pin's ABS MAX rating, please refer to page 14, Enable/SYNC control section.
• 1. The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θ JA , and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by P D (MAX) = (T J (MAX)-TA)/ θ JA . Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.
• 1. The device is not guaranteed to function outside of its operating conditions.
• 1. Measured on JESD51-7, 4-layer PCB.

Thermal shutdown prevents the chip from operating at exceedingly high temperatures. When the silicon die temperature exceeds 170°C, it shuts down the whole chip. When the temperature drops below its lower threshold (typically 140°C) the chip is enabled again.

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