ZHCSHA3D NOVEMBER 2009 – March 2018 TPS40303 , TPS40304 , TPS40305
PRODUCTION DATA.
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
BOOT | 6 | I | Gate drive voltage for the high-side N-channel MOSFET. A 0.1-µF capacitor (typical) must be connected between this pin and SW. For low input voltage operation, an external schottky diode from BP to BOOT is recommended to maximize the gate drive voltage for the high-side. |
BP | 10 | O | Output bypass for the internal regulator. Connect a low ESR bypass ceramic capacitor of 1 µF or greater from this pin to GND. |
COMP | 4 | O | Output of the error amplifier and connection node for loop feedback components. |
EN/SS | 2 | I | Logic level input which starts or stops the controller via an external user command. Letting this pin float turns the controller on. Pulling this pin low disables the controller. This is also the soft-start programming pin. A capacitor connected from this pin to GND programs the soft-start time. The capacitor is charged with an internal current source of 10 µA. The resulting voltage ramp of this pin is also used as a second non-inverting input to the error amplifier after a 0.8 V (typical) level shift downwards. Output regulation is controlled by the internal level shifted voltage ramp until that voltage reaches the internal reference voltage of 600 mV – the voltage ramp of this pin reaches 1.4 V (typical). Optionally, a 267-kΩ resistor from this pin to BP enables the FSS feature. |
FB | 5 | I | Inverting input to the error amplifier. In normal operation, the voltage on this pin is equal to the internal reference voltage. |
HDRV | 7 | O | Bootstrapped gate drive output for the high-side N-channel MOSFET. |
LDRV/OC | 9 | O | Gate drive output for the low-side synchronous rectifier N-channel MOSFET. A resistor from this pin to GND is also used to determine the voltage level for OCP. An internal current source of 10 µA flows through the resistor during initial calibration and that sets up the voltage trip point used for OCP. |
PGOOD | 3 | O | Open-drain power good output. |
SW | 8 | O | Sense line for the adaptive anti-cross conduction circuitry. Serves as common connection for the flying high-side FET driver. |
VDD | 1 | I | Power input to the controller. Bypass VDD to GND with a low ESR ceramic capacitor of at least 1-µF close to the device. |
GND | Thermal Pad | — | Ground connection to the controller. This is also the thermal pad used to conduct heat from the device. This connection serves a twofold purpose. The first is to provide an electrical ground connection for the device. The second is to provide a low thermal impedance path from the device die to the PCB. This pad should be tied externally to a ground plane. |