ZHCSQ77B February 2023 – June 2024 TPS25948
PRODUCTION DATA
For all applications, a ceramic decoupling capacitor of 0.1 μF or greater is recommended between the IN terminal and GND terminal.
The optimal placement of the decoupling capacitor is closest to the IN and GND terminals of the device. Care must be taken to minimize the loop area formed by the bypass-capacitor connection, the IN terminal, and the GND terminal of the IC.
High current-carrying power-path connections must be as short as possible and must be sized to carry at least twice the full-load current.
The GND terminal must be tied to the PCB ground plane at the terminal of the IC with the shortest possible trace. The PCB ground must be a copper plane or island on the board. It's recommended to have a separate ground plane island for the eFuse. This plane doesn't carry any high currents and serves as a quiet ground reference for all the critical analog signals of the eFuse. The device ground plane should be connected to the system power ground plane using a star connection.
The IN and OUT pads are used for heat dissipation. Connect to as much copper area on top and bottom PCB layers using as possible with thermal vias. The vias under the device also help to minimize the voltage gradient accross the IN and OUT pads and distribute current unformly through the device, which is essential to achieve the best on-resistance and current sense accuracy.
Locate the following support components close to their connection pins:
RILM
CdVdT
CITIMER
Resistors for the EN/UVLO and OVLO pins
Connect the other end of the component to the GND pin of the device with shortest trace length. The trace routing for the RILM, CITIMER and CdVdt components to the device must be as short as possible to reduce parasitic effects on the current limit , overcurrent blanking interval and soft start timing. It's recommended to keep parasitic capacitance on ILM pin below 50 pF to ensure stable operation. These traces must not have any coupling to switching signals on the board.
Since the bias current on ILM pin directly controls the overcurrent protection behavior of the device, the PCB routing of this node must be kept away from any noisy (switching) signals.
Protection devices such as TVS, snubbers, capacitors, or diodes must be placed physically close to the device they are intended to protect. These protection devices must be routed with short traces to reduce inductance. For example, a protection Schottky diode is recommended to address negative transients due to switching of inductive loads. It's also recommended to add a ceramic decoupling capacitor of 1 μF or greater between OUT and GND. These components must be physically close to the OUT pins. Care must be taken to minimize the loop area formed by the Schottky diode/bypass-capacitor connection, the OUT pin and the GND terminal of the IC.