LTC3644/
LTC3644-2

Demonstration circuit 2383A-B features the LT3644-2: the wide input and output voltage range, high efficiency and power density, quad 1.25A outputs DC/DC synchronous step-down monolithic regulator. The input voltage range of DC2383A-A is 2.7V to 17V. The default demo board setting of V_OUT1, V_OUT2, V_OUT3, V_OUT4 is 1.2V, 3.3V, 2.5V, and 1.8V at 1.25A maximum DC output current per channel respectively. There are two assembly versions. The DC2383A-B features LTC3644-2 which operates at an internally fixed frequency of 2.25MHz (Typ), while the DC2383A-A features LTC3644 which operates at an internally fixed frequency of 1MHz (Typ). Peak current limit is internally fixed at 2.2A typical per channel. Each channel comes with independent run pin control and power good indicators. Phase shift selection of either 0 degree or 180 degrees between switch rising edge of channels 1, 2 and channels 3, 4 is also available.

DC2383A-B provides optional onboard 0Ω jumpers to configure the LTC3644-2 as 4-phase dual 2.5A/2.5A outputs or 4-phase triple 2.5A/1.25A/1.25A outputs. Optional 0Ω jumpers connecting V_IN1 to V_IN2, V_IN3, and V_IN4 are available for users to operate selected channels of LTC3644-2 at different input voltages than V_IN1.

A user-selectable MODE/SYNC input is provided to allow users to trade off ripple noise for light load efficiency: pulse-skipping mode (PS) or Burst Mode^® operation delivers higher efficiency at light load while forced continuous conduction mode (FCM) is preferred for noise sensitive applications. The MODE/SYNC pin can also be used to synchronize the switching frequency to an external clock or set the phase shift between channels 1, 2 and channels 3, 4. Constant frequency; peak current mode control architecture; and an integrated, internal control loop compensation network allow very fast transient responses to line and load changes while maintaining loop stability.

The LTC3644-2 is available in a thermally enhanced, low profile 36-lead 5mm × 5mm BGA package.

It is recommended to read the LTC3644-2 data sheet and demo board manual prior to using or making any changes to DC2383A-B.

Demonstration circuit 2383A-A features the LTC3644: the wide input and output voltage range, high efficiency and power density, quad 1.25A outputs DC/DC synchronous step-down monolithic regulator. The input voltage range of DC2383A-A is 2.7V to 17V. The default demo board setting of V_OUT1, V_OUT2, V_OUT3, V_OUT4 is 1.2V, 3.3V, 2.5V and 1.8V at 1.25A maximum DC output current per channel. There are two assembly versions. The DC2383A-A features LTC3644 which operates at an internally fixed frequency of 1MHz (Typ), while the DC2383A-B features LTC3644-2 which operates at an internally fixed frequency of 2.25MHz (Typ). Peak current limit is internally fixed at 2.2A typical per channel. Each channel comes with independent run pin control and power good indicators. Phase shift selection of either 0 degree or 180 degrees between switch rising edge of channels 1, 2 and channels 3, 4 is also available.

DC2383A-A provides optional onboard 0Ω jumpers to configure the LTC3644 as 4-phase dual 2.5A/2.5A outputs or 4-phase triple 2.5A/1.25A/1.25A outputs. Optional 0Ω jumpers connecting V_IN1 to V_IN2, V_IN3, V_IN4 are available for users to operate selected channels of LTC3644 at different input voltages than V_IN1.

A user-selectable MODE/SYNC input is provided to allow users to trade off ripple noise for light load efficiency: pulse-skipping mode (PS) or Burst Mode^® operation delivers higher efficiency at light load while forced continuous conduction mode (FCM) is preferred for noise sensitive applications. The MODE/SYNC pin can also be used to synchronize the switching frequency to an external clock or set the phase shift between channels 1, 2 and channels 3, 4. Constant frequency, peak current mode control architecture and integrated internal control loop compensation network, allows very fast transient response to line and load changes while maintaining loop stability.

The LTC3644 is available in a thermally enhanced, low profile 36-lead 5mm × 5mm BGA package.

It is recommended to read the data sheet and demo manual of LTC3644 prior to using or making any changes to DC2383A-A.