www.basicsemi.com

12/19

Rev.0.0

Dual-ChannelIsolatedGateDriver

BTD21520x

9.3InputStageCharacteristics

With input pins and secondary side completely isolated, BTD21520 is designed to be compatible with CMOS levels, and

supports 3.3V, 5V and 15V level input, making the chip easy to accept control of multiple logic levels.Inputs with Schmitt

stage for improved anti-interference performance.INx, PWM, and DIS have a built-in 200kΩ resistor pulled down to the

ground, ensuring that the output of the device is low when input left open. However, in order to ensure the initial pow-

er-on state of the device, BASiC recommends adding an appropriate pull-up or pull-down resistor to the input.

9.4OutputBoosterCharacteristic

The BTD21520 has a rail-to-rail booster stage output. The pull-up structure of the output stage consists of

a P-channel MOSFET and an N-channel MOSFET connected in parallel. At turn-on, N-channel MOSFET provides

high current driving capability. P-channel MOSFET provides a small steady-state conduction voltage drop during

steady conduction. The PMOS on-resistance (RPMOS_ON) is 6.5Ω, and the NMOS on-resistance (RNMOS_ON) is 0.5Ω.

The pull-down structure is implemented using an N-channel MOSFET. A 1MΩ resistor is connected in parallel between

the drain and gate of the MOSFET to effectively clamp the gate voltage of the power device in the event of a loss of pow-

er on the chip to prevent the occurrence of partial turn-on.However, in order to ensure reliable shutdown of the power

device, BASiC recommends that appropriate pull-down resistor be added to the gate.

Figure8.OutputCharacteristicsDiagram

9.5DeviceFunction

9.5.1Disable

When the DIS pin is set to a high level, both outputs can be shut down at the same time. The device operates normally

when the DIS pin is grounded or left open. The response time of the disable function is within 20ns. The disable function

is activated or deactivated according to the setting only when the VCC is kept above the undervoltage turn-on threshold.

If the DIS pin is not used, it is recommended to connect it to the ground. If connecting DIS pin to a microcontroller with

distance, it is recommended to bypass the DIS pin with a low ESR/ESL capacitor of approximately 1nF for better noise

immunity.

9.5.2PullingDTPinUptoVCC

The two channels are independent, with output exactly matching input, and no dead time is inserted, allowing the out-

put signals to be both high.

9.5.3DeadTimeSetting

DT pin sets the dead time.It is used to set the dead time between channel 1 and channel 2 to prevent them from shoot-

through. The steady-state voltage of DT pin is 0.8V, and the current value of the pin is measured for corresponding dead

time. The dead time is calculated as TDT=10×RDT. The unit of tDT is ns and the unit of RDT is kΩ. To ensure that the pin

signal is not interfered, it is recommended to place a 2.2nF capacitor near the IC between DT pin and GND, and it is not

recommended to left DT pin open.

VEE

VDD

Level Shifting and

Control Logic

RPMOS_ON

RNMOS_ON

ROL

OUT