LMR51430XFDDCR

Part: LMR51430XDDCR — Texas Instruments

Type: Synchronous Buck Converter

Description: 4.5–36 V input, 3 A synchronous buck converter with integrated FETs, 500 kHz fixed switching frequency (PFM variant) and 0.6 V ±1.5% reference in a 6-pin SOT-23 package.

Operating Conditions:

• Supply voltage (VIN): 4.5–36 V
• Operating junction temperature: -40 to 150 °C
• Output voltage: 0.6 V to 95% of VIN
• Output current: 3 A

Absolute Maximum Ratings:

• Max supply voltage (VIN): 38 V
• Max SW voltage: 38 V (DC); -3.0 V to 38 V for transients < 20 ns
• Max junction temperature: 150 °C
• Storage temperature: -65 to 150 °C

Key Specs:

• Reference voltage (VFB): 0.591 / 0.6 / 0.609 V (min/typ/max)
• Switching frequency (500 kHz option, CCM): 450 / 500 / 560 kHz
• Quiescent current (VEN = 3 V, non-switching, PFM variant): 40 μA typ, 65 μA max
• Shutdown supply current (VEN = 0 V): 3 μA typ, 15 μA max
• High-side / low-side RDS(on) (TJ = 25 °C): 0.12 Ω / 0.07 Ω
• High-side peak current limit: 3.67 / 4.76 / 6.68 A
• Low-side valley current limit: 2.75 / 3.5 / 4.2 A
• Internal soft-start time: 4.0 ms typ (3.2–5.4 ms)
• VIN UVLO rising threshold: 3.89 V typ, 4.5 V max
• Minimum on-time: 70 ns (VIN = 12 V, IOUT = 3 A)
• Thermal shutdown: 163 °C typ, 22 °C hysteresis

Features:

• Functional Safety-Capable
• 4.5–36 V input range, 3 A continuous output current
• 70 ns minimum on-time, 98% maximum duty cycle
• 500 kHz and 1.1 MHz fixed frequency options; PFM and FPWM variants
• ±1.5% tolerance voltage reference
• Precision enable with adjustable UVLO
• Internal compensation and soft-start
• Start-up with prebiased output
• Cycle-by-cycle current limit, hiccup-mode short-circuit protection, thermal shutdown
• Pin-to-pin compatible with TPS54202 and TPS54302

Applications:

• Appliances
• Building automation
• Motor drives
• General purpose wide VIN power supplies

Package:

• SOT-23, 6 pins (2.90 mm × 1.60 mm nominal body size)

• Functional Safety-Capable
• -Documentation available to aid functional safety system design
• Configured for rugged industrial applications
• -4.5-V to 36-V input voltage range
• -3-A continuous output current
• -70-ns minimum switching on time
• -500-kHz and 1.1-MHz fixed switching frequency options
• --40°C to 150°C junction temperature range
• -98% maximum duty cycle
• -Start-up with prebiased output
• -Internal short circuit protection with hiccup mode
• -±1.5% tolerance voltage reference
• -Precision enable
• Small solution size and ease of use
• -Integrated synchronous rectification
• -Internal compensation for ease of use
• -SOT-23 package
• Pin-to-pin compatible with the TPS54202 and TPS54302
• PFM and forced PWM (FPWM) options available
• Create a custom design using the LMR51430 with the WEBENCH ® Power Designer

• Appliances
• Building automation
• Motor drives
• General purpose wide VIN power supplies

Simplified Schematic

Figure 6-1. 6-Pin SOT-23 DBV Package (Top View)

Table 6-1. Pin Functions

Table 6-1. Pin Functions

Limits apply over operating junction temperature (T J ) range of -40°C to +150°C, unless otherwise stated. Minimum and maximum limits (1) are specified through test, design or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise stated, the following conditions apply: V IN = 4.5 V to 36 V.

Over operating junction temperature range (unless otherwise noted) (1)

Over the recommended operating junction temperature range of -40°C to 150°C (unless otherwise noted) (1)

The value of RθJA given in this table is only valid for comparison with other packages and cannot be used for design purposes. These values were calculated in accordance with JESD 51-7, and simulated on a 4-layer JEDEC board. They do not represent the performance obtained in an actual application. For example, with a 2-layer PCB, a R θJA = 80 °C /W can be achieved. For design information, see Maximum Output Current Versus Ambient Temperature.

The LMR51430 is a step-down DC-to-DC converter. The device is typically used to convert a higher input voltage to a lower output DC voltage with a maximum output current of 3 A. The following design procedure can be used to select components for the LMR51430. Alternately, the WEBENCH ® software can be used to generate complete designs. When generating a design, the WEBENCH software uses iterative design procedure and accesses comprehensive databases of components. Go to ti.com for more details.

• (1) For all available packages, see the orderable addendum at the end of the data sheet.

D003_SLUSEF4.grf

Efficiency vs Output Current, VOUT = 5 V, 500 kHz