Features

• Ultrawide Input Voltage Range: 3V to 100V
• Output Voltage Range: 0.8V to 60V
• Internal Synchronous Switches
• Low Ripple Burst Mode® Operation:
  16μA I_Q at 12V_IN to 5V_OUT Output Ripple <10mV_P-P
  7μA I_Q at 48V_IN to 5V_OUT Output Ripple <10mV_P-P
• Low Dropout: 99% Maximum Duty Cycle
• Peak Current Mode Control
• Fixed Frequency Operation: 100kHz to 1MHz
• Synchronization Input
• Programmable Undervoltage Lockout
• Power Good Flag
• Flexible Output Voltage Tracking
• Short-Circuit Protection
• Low Shutdown Current: 5μA
• Tolerates Pin Open/Short Faults
• Thermally Enhanced 20-Lead TSSOP with High Voltage Lead Spacing

Typical Application

Description

The LT®8631 is a current mode PWM step-down DC/DC converter with internal synchronous switches that provide current for output loads up to 1A. The wide input range of 3V to 100V makes the LT8631 suitable for regulating power from a wide variety of sources, including automotive and industrial systems and 36V to 72V telecom supplies. Low ripple Burst Mode operation enables high efficiency operation down to very low output currents while keeping the output ripple below 10mV_P-P. Resistor programmable 100kHz to 1MHz frequency range and synchronization capability enable optimization between efficiency and external component size. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, while also providing output tracking. A power good flag signals when the output voltage is within ±7.5% of the regulated output. Undervoltage lockout can be programmed using the EN/UV pin. Shutdown mode reduces the total quiescent current to < 5μA. The LT8631 is available in a 20-lead TSSOP package with exposed pad for low thermal resistance and high voltage lead spacing.