L6738ATR STMicroelectronics, L6738ATR Datasheet - Page 13

• Manufacturer Part Number: L6738ATR
• Description: IC PWM CTLR 1PH STPDN 16-VFQFPN
• Manufacturer: STMicroelectronics

Specifications of L6738ATR

• Frequency - Max: 220kHz
• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Duty Cycle: 100%
• Voltage - Supply: 5 V ~ 12 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-11012-2

L6738A
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Device description and operation
The L6738A is a single-phase PWM controller with embedded high-current drivers that
provides complete control logic and protections to realize a general DC-DC step-down
converter. Designed to drive N-channel MOSFETs in a synchronous buck topology, with its
high level of integration, this 16-pin device allows a reduction of cost and size of the power
supply solution and also provides real-time PGOOD in a compact VFQFPN16 3x3 mm.
The L6738A is designed to operate from a 5 V or 12 V supply. The output voltage can be
precisely regulated to as low as 0.8 V with ±0.5 % accuracy over line and temperature
variations. The controller performs remote GND recovery to prevent losses and GND drops
to affect the regulation.
The switching frequency is internally set to 200 kHz and adjustable through the OSC pin.
The IC can be disabled by pulling the OSC pin low.
The L6738A provides a simple control loop with a voltage-mode error-amplifier. The error-
amplifier features a 15 MHz gain-bandwidth product and 8 V/µs slew rate, allowing high
regulator bandwidth for fast transient response.
To avoid load damages, the L6738A provides overcurrent protection, and overvoltage and
undervoltage protection. The overcurrent trip threshold is monitored through the inductor
DCR, assuring optimum precision, saving the use of an expensive and space-consuming
sense resistor. The output voltage is monitored through the dedicated VSEN pin.
The L6738A implements soft-start by increasing the internal reference in closed loop
regulation. The low-side-less feature allows the device to perform the soft-start over pre-
biased output avoiding high current return through the output inductor and dangerous
negative spikes at the load side.
The L6738A is available in a compact VFQFN16 3x3 mm package with exposed pad.
Doc ID 18134 Rev 1
Device description and operation
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