Infineon TDA21535AUMA1

High frequency, low profile DC-DC converters; Voltage Regulators for DDR memory arrays, and low current voltage rails;

The TDA21535 integrated power-stage contains a low quiescent current synchronous buck gate-driver IC which is co-packed with control and synchronous MOSFETs along with an active diode structure that achieves low Vsd similar to a schottky with very little reverse recovery charge. The package is optimized for PCB layout, heat transfer, driver/MOSFET control timing, and minimal switch node ringing when layout guidelines are followed. The paired gate driver and MOSFET combination enables higher efficiency at lower output voltages.

The internal MOSFET sensing achieves superior current sense accuracy vs. best-in-class controller-based Inductor DCR sense methods.

Protection includes IC temperature reporting and over temperature protection feature (OTP with thermal shutdown), cycle-by-cycle over current protection (OCP), control MOSFET short detection (HSS - High side short detection), VDRV and bootstrap under-voltage protection. The TDA21535 also features "refreshing" of bootstrap capacitor to prevent the bootstrap capacitor from over-discharging.

Operation of up to 1.5 MHz switching frequency enables high performance transient response, allowing miniaturization of output inductors, as well as input and output capacitors while maintaining industry leading efficiency.

The TDA21535 contains an improved high speed MOSFET driver optimized to drive a pair of co-packaged high-side and low-side OptiMOS MOSFETs at frequency up to 1.5 MHz. Dc-dc controllers using traditional current sense methods like DCR sensing and Rdson sensing typically have limitations. DCR current sensing is sensitive to temperature changes of the inductor and needs temperature compensation either implemented externally using a thermos-couple or inside the power stage. Rdson current sensing, on the other hand, is not dependent on the inductor but there is a temperature co-efficient associated with the MOSFET rdson. Besides, it is difficult to implement rdson current sensing for high-side MOSFET which is therefore replaced by emulated current while the low-side current is sensed across the MOSFET. With the advanced current-mirror sensing in TDA21535, all these limitations are eliminated while achieving superior accuracy. Current on both high-side as well as low-side MOSFET is mirrored on a sense MOSFET which is a part of the main MOSFET device, and hence comes with an inherent temperature compensation without the need for an additional circuitry. Real current-sensing on both MOSFET ensures that the system

• Integrated driver, active diode, high-side MOSFET and low-side MOSFET
• Input voltage range of 4.25 V to 16 V
• VCC supply of 4.25 V to 5.5 V
• Output voltage range from 0.225 V up to 5.5 V
• Output current capability of 35 A
• Operation up to 1.5 MHz
• VCC under voltage lockout (UVLO)
• Bootstrap under voltage protection
• On-chip MOSFET current sensing and reporting with 5 μA/A gain
• Over temperature protection and thermal shutdown
• Cycle-by-cycle over current protection and flag
• High-side MOSFET short detection and flag
• Auto-replenishment on bootstrap capacitor
• Compatible with 3.3 V tri-state PWM Input
• Auto SLEEP mode after 20 μs of PWM Tri-state (1.7 mA typ)
• DEEP SLEEP mode for power saving via EN = low (32 μA typ)
• Small 4 mm x 5 mm x 0.9 mm PQFN package
• Lead free RoHS compliant package