MAX8723ETE+

19-3949 Rev 0; 4/06 KIT ATION EVALU E L B AVAILA Low-Cost, Internal-Switch, Step-Down Regulator for LCD Displays The MAX8723 is a high-efficiency, switch-mode, stepdown regulator with a 14V internal power switch. With only a few external passive components, this low-cost regulator can generate a fixed 3.3V or adjustable DC output voltage of 2.0V to 3.6V of 2.0V to 3.6V (dual mode) from a 6V to 13.2V DC source. The 13.2V input voltage range makes this part ideal for LCD displays, point-of-load regulators, and other 8/12V-powered industrial equipment applications. The MAX8723 can deliver up to 2A. It features an internal power MOSFET, a built-in bootstrap diode for its MOSFET driver, and an interface for an external synchronous rectifier MOSFET drive to replace the Schottky diode and improve efficiency. Its fixed-frequency PWM/skip-mode operation and current-mode control architecture provide fast load-transient response without compensation. The switching frequency is a pin-selectable 500kHz, 1MHz, or 1.5MHz, minimizing the size of external components. The MAX8723 has built-in soft-start, current-limit, thermal-shutdown, and timer-delayed output-fault shutdown functions. The soft-start function limits inrush current during startup, avoiding transients that can trigger front-end protection circuits and lock up the system. The current limit, thermal-shutdown, and timer-delayed output-fault shutdown functions protect the power supply against fault conditions. The MAX8723 also includes a linear regulator (VL), which provides a fixed 5V output (25mA) to support small external loads. The reference output is high-precision (2V ± 1%) and can also supply small external load currents. The MAX8723 is available in the 16-pin 4mm x 4mm thin QFN package. Features ♦ 6V to 13.2V Input Supply Range ♦ Integrated 14V 2A n-Channel MOSFET Switch ♦ Preset 1.5% Accurate 3.3V Fixed Output Voltage or 2.0V to 3.6V Adjustable Output (Dual Mode) ♦ Current-Mode PWM Operation ♦ Frequency-Selectable 500kHz/1MHz/1.5MHz ♦ Internal 5V Linear Regulator Supports Up to 25mA External Load ♦ 2V Precision Reference (1%) ♦ Integrated Bootstrap Diode for High-Side MOSFET Drive ♦ ♦ ♦ ♦ ♦ ♦ External Synchronous Rectifier Driver Built-In Soft-Start 200µA Standby Mode Timer-Delayed Output Fault Protection Thermal Shutdown Protection Small 16-Pin 4mm x 4mm Thin QFN Package Ordering Information PART TEMP RANGE PIN-PACKAGE PKG CODE MAX8723ETE+ -40°C to +85°C 16-pin Thin QFN 4mm x 4mm T1644-4 +Denotes lead-free package. Simplified Operating Circuit IN CINL INL Applications LCD TVs LCD Monitors Digital System Power Supplies Point-of-Load Regulators 8/12V Industrial Equipment REF BST CREF IN VCC SHDN VCC2 VL CVL GND CIN CBST LX MAX8723 L D OUT COUT PGND FSEL Pin Configuration appears at end of data sheet. EXT OUT I.C. EP FB ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX8723 General Description MAX8723 Low-Cost, Internal-Switch, Step-Down Regulator for LCD Displays ABSOLUTE MAXIMUM RATINGS IN, INL to GND .......................................................-0.3V to +14V SHDN, VCC2, OUT, VL, VCC, I.C. to GND...............-0.3V to +6V FB, FSEL, REF to GND.................................-0.3V to VCC + 0.3V EXT to GND .....................................................-0.3V to VL + 0.3V GND to PGND .......................................................-0.3V to +0.3V BST to GND ............................................................-0.3V to +20V LX to BST..................................................................-6V to +0.3V LX to GND........................................................-0.3V to IN + 0.3V VL Short Circuit to GND..............................................Momentary RMS LX Current ....................................................................1.6A Continuous Power Dissipation (TA = +70°C) 16-Pin 4mm x 4mm Thin QFN (derated 25mW/°C above +70°C)..............................2000mW Operating Temperature Extended.......................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (Circuit of Figure 1 with 1.5MHz components of Table 1, unless otherwise specified. VIN = V INL = 12V, V OUT = +3.3V, PGND = GND = 0, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL IN, INL Input Voltage Range 6.0 INL Quiescent Current FB = 1.8V, EXT unconnected INL Standby Supply Current VINL = 6V to 13.2V, SHDN = GND 6 13.2 V 12 mA 0.5 mA FSEL = GND 1275 1500 1725 FSEL = VCC 850 1000 1150 FSEL = REF 425 500 590 VL Output Voltage 6V < VINL < 13.2V, VFB = 1.8V, EXT unconnected, IVL = 25mA 4.9 5.0 5.1 V VL Undervoltage Lockout Threshold VL rising, hysteresis = 2.5% 3.6 4.0 4.4 V REF Output Voltage No external load 1.98 2.00 2.02 V REF Load Regulation 0 < ILOAD < 50µA 10 mV REF Sink Current In regulation REF Undervoltage Lockout Threshold Rising edge 1.5 Falling edge 1.3 Operating Frequency kHz VL REGULATOR REFERENCE 10 µA V STEP-DOWN REGULATOR OUT Voltage in Fixed Mode VIN = 6.0V to 13.2V, IOUT = 0.5A (Note 1) 3.25 3.30 3.35 V FB Voltage in Adjustable Mode Duty cycle = 20% to 35%, IOUT = 0.5A (Note 1) 1.97 2.00 2.03 V FB Adjustable-Mode Threshold Voltage Dual-mode comparator 0.10 0.15 0.20 V 3.6 V Output Voltage Adjust Range 2 2.0 _______________________________________________________________________________________ Low-Cost, Internal-Switch, Step-Down Regulator for LCD Displays (Circuit of Figure 1 with 1.5MHz components of Table 1, unless otherwise specified. VIN = V INL = 12V, V OUT = +3.3V, PGND = GND = 0, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS Step-Down Regulator Fault Trip Level 3.3V fixed mode, OUT falling FB Input Bias Current VFB = 2.0V FB adjustable mode, FB falling MIN TYP MAX 2.640 1.536 1.600 1.664 50 125 200 Low-Frequency Operation OUT Threshold 1.3 UNITS V nA V FSEL = GND 250 FSEL = VCC 167 FSEL = REF 83 DC Load Regulation 0 < IOUT < 2A 0.5 % DC Line Regulation 6V