The R1273 is a step-down DC/DC converter which can generate an output voltage of 0.7 V to 5.3 V by driving high- / low-side NMOSs. By the adoption of a unique current mode PWM architecture without an external current sense resistor, the R1273 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 R1273 can achieve a high-speed response to variations of input voltage and load current. The user-settable oscillation frequency is adjustable over a range of 250 kHz to 1 MHz by external resistors, and also can be synchronized to an external clock in a range of 250 kHz to 1 MHz. The R1273 supports 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 R1273 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, a hiccup-mode short-circuit protection (non-latch type), a thermal shutdown function, an UVLO (Under Voltage Lock Out) function, an OVD (Over Voltage Detection) function, a soft-start function, a low-inductor current shutdown function, and so on. Also, a power good function provide 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. The R1273 is available in QFN0505-32B package.
消费 工业 车载 输入电压范围 4.0 V to 34.0 V (36.0 V) 工作温度范围 -40°C to 105°C (125°C) -40°C to 105°C (125°C) -40°C to 125°C (150°C) 电源电流 Typ. 15 µA 待机电流 Typ. 3 µA 启动电压 4.5 V 输出电压范围 Externally Adjustable: 0.7 V to 5.3 V 反馈电压 0.64 V 反馈电压精度 ±1% 驱动器导通电阻 High-side: Typ. 11.8 mΩ / Low-side: Typ. 12.3 mΩ 振荡器频率 Externally Adjustable: 250 kHz to 1 MHz 封装 QFN0505-32B
TSD ILX OCP OVP UVLO OVLO Reverse Shutdown Soft Start SSCG PGOOD Auto Discharge Anti-ringing Sequencing Max Duty Ext. Phase LED Adjust
Efficiency vs. Output Current
|ILX||LX Current Limit Function|
|OVLO||Overvoltage Lockout Protection|
|SSCG||Spread Spectrum Clock Generator Function|
|PGOOD||Power Good Output|
|Anti-ringing||Anti-ringing Switch Function|
|Sequencing||Start-up Sequencing Control|
|LED Adjust||LED High-speed Dimming Control|