Texas Instruments LM25137-Q1 Synchronous Buck Controller
Texas Instruments LM25137-Q1 Synchronous Buck Controller is a 42V synchronous buck DC-DC controller with three options for functional safety (capable, ASIL B, and ASIL D). The device uses an interleaved, stackable, peak current-mode architecture for fast transient response, easy loop compensation, excellent line and load regulation, and accurate current sharing with paralleled phases for high output current. A high-side switch with a minimum on-time of 22ns facilitates large step-down ratios. This feature enables the direct conversion from 12V and 24V automotive inputs to low-voltage rails for reduced system design cost and complexity. The LM25137-Q1 continues to operate during input voltage dips as low as 4V, at 100% duty cycle if needed. The operating run-time in battery-powered automotive systems is extended by a 9µA no-load quiescent current with the output voltage in regulation.
Several features are included in the Texas Instruments LM25137-Q1 to simplify compliance with CISPR 25 and automotive EMI requirements. High-current MOSFET gate drivers that are adaptively timed minimize body diode conduction during switching transitions, improving thermal and EMI performance and reducing switching losses at high switching frequency and high input voltage. To reduce the EMI filter size and input capacitor ripple current, 180° interleaved operation is provided for two outputs. A 90° out-of-phase clock output works well for multichannel, multiphase, or cascaded power stages. Resistor-adjustable switching frequency can be synchronized to an external clock source up to 2.5MHz, with a frequency as high as 2.2MHz to eliminate beat frequencies in noise-sensitive applications.
Features
- AEC-Q100 qualified for automotive applications with a device temperature grade 1 (-40°C to +125°C ambient operating temperature)
- Functional safety-capable, with documentation available to aid functional safety system design
- Functional safety-compliant options of ASIL B and ASIL D are available
- Dual-channel synchronous buck DC-DC controller
- Wide input voltage range of 4V to 42V
- 1% accurate, fixed 3.3V, 5V, 12V, or adjustable outputs from 0.8V to 36V
- 150°C maximum junction temperature
- Charge-pump gate drivers for 100% duty cycle
- Two interleaved synchronous buck channels
- Dual-channel or single-output multiphase
- Stackable up to four phases
- SYNC in and SYNC out capability
- Inherent protection features for robust design
- Internal hiccup-mode overcurrent protection
- Independent ENABLE and PGOOD functions
- Adjustable output voltage soft start
- VCC and gate-drive UVLO protection
- Thermal shutdown protection with hysteresis
- Designed for ultra-low EMI requirements
- Dual Random Spread Spectrum (DRSS)
- Switching frequency from 100kHz to 2.5MHz
- VQFN-36 package with wettable flanks
Applications
- Automotive electronic systems
- Infotainment systems, instrument clusters
- Advanced driver assistance systems (ADAS)
- Body electronics and lighting
Simplified Schematic - Dual-Output Buck Switching Regulator
