R1272S032A033-0500EV 34 V Input Synchronous Step-down DC / DC Controller Evaluation Board NO.EEV-351-032A033-0500-200729 R1272S032A033-0500EV is the evaluation board for R1272 which has the below features, benefits and specifications. OUTLINE The R1272S is a step-down DC/DC controller which can generate an output voltage of 0.7 V to 5.3 V by driving external high- / low-side NMOSs. By the adoption of a unique current mode PWM architecture without an external current sense resistor, the R1272S can make up a stable DC/DC converter with high-efficiency even if adding low Ron MOSFETs and a low DCR inductor externally. And, by the frequency characteristics optimization with using external phase compensation capacitor, the R1272S can achieve a high-speed response to variations of input voltage and load current. The user-settable oscillation frequency is adjustable (1) over a range of 250 kHz to 1 MHz by external resistors, and also can be synchronized to an external clock. Output Voltage Control Methods have three operating modes: Forced PWM mode, PLL PWM mode, and PWM/VFM Auto-switching mode. These modes are selectable according to conditions of the MODE pin. Especially, the PWM/VFM Auto-switching mode can improve efficiency under light load conditions. The R1272S can minimize the output voltage drop caused by an input voltage drop at cranking, with reducing the operating frequency (the lowest possible limit is a quarter of the frequency) so that the off-duty is reduced. Protection functions include a current limit function, an UVLO (Under Voltage Lock Out) function, an OVP (Over Voltage Protection) function, a soft-start function, a low-inductor current shutdown function, and so on. Also, a power good function provides the status of output with using a power good (PGOOD) pin. For EMI reduction, SSCG (Spread-Spectrum Clock Generator) for diffused oscillation frequency at the PWM operation is optionally available. FEATURES Operating Voltage (Maximum Rating) 4.0 V to 34 V (36 V) Operating Temperature Range -40C Ta 105C (Usable in high-temperature environment) Start-up Voltage 4.5 V Output Voltage 3.3 V Feedback Voltage Tolerance 0.64 V 1% Consumption Current at No Load (at VFM mode) Typ.15 A Adjustable Oscillation Frequency 500 kHz Synchronizable Clock Frequency 250 kHz to 1 MHz Spreading Rate for SSCG Typ. 3.6% Minimum On-Time Typ.100 ns Minimum Off-Time Typ.120 ns (at regulation mode) At dropout, actual minimum off-time is reduced. (1) Adjustable Soft-start Time Typ.500 s Pre-bias Start-up (1) 500 s (Typ.) as a lower limit with using an external capacitor. Otherwise, available the tracking function through the application of an external voltage. 1 R1272S NO.EEV-351-032A033-0500-200729 Anti-phase Clock Output Thermal Shutdown Function Tj = 160C (Typ.) Under Voltage Lockout (UVLO) Function Typ. 3.3 V Over Voltage Detection (OVD) Function FB pin voltage (V ) + 10% (Typ.) FB Detection/Release Hysteresis FB pin voltage (VFB) x 3% (Typ.) ) - 10% (Typ.) Under Voltage Detection (UVD) Function FB pin voltage (VFB Detection/Release Hysteresis FB pin voltage (V ) x 3% (Typ.) FB Over-current Protection Hiccup-mode / Latch mode Selectable Current Limit Threshold 70 mV Power Good Output NMOS Open-drain Output Package HSOP-18 For more details on R1272 IC, please refer to