FAM6502MP45X

FAN5602_09 FAIRCHILD | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 13

Technical content

Features

■Low-Noise, Constant-Frequency Operation at Heavy Load ■High-Efficiency, Pulse-Skip (PFM) Operation at Light Load ■Switch Configurations (1:3, 1:2, 2:3, 1:1, 3:2, 2:1, 3:1) ■92% Peak Efficiency ■Input Voltage Range: 2.7V to 5.5V ■Output Current: 4.5V, 100mA at VIN = 3.6V ■±3% Output Voltage Accuracy ■ICC < 1µA in Shutdown Mode ■1MHz Operating Frequency ■Shutdown Isolates Output from Input ■Soft-Start Limits Inrush Current at Startup ■Short-Circuit and Over-Temperature Protection ■Minimum External Component Count ■No Inductors

Applications

■Cell Phones ■Handheld Computers ■Portable RF Communication Equipment ■Core Supply to Low-Power Processors ■Low-Voltage DC Bus ■DSP Supplies

Description

The FAN5602 is a universal switched capacitor DC/DC converter capable of step-up or step-down operation. Due to its unique adaptive fractional switching topology, the device achieves high efficiency over a wider input/ output voltage range than any of its predecessors. The FAN5602 utilizes resistance-modulated loop control, which produces lower switching noise than other topolo- gies. Depending upon actual load conditions, the device automatically switches between constant-frequency and pulse-skipping modes of operation to extend battery life. The FAN5602 produces a fixed regulated output within the range of 2.7V to 5.5V from any type of voltage source. High efficiency is achieved under various input/ output voltage conditions because an internal logic circuit automatically reconfigures the system to the best possi- ble topology. Only two 1µF bucket capacitors and one 10µF output capacitor are needed. During power on, soft-start circuitry prevents excessive current drawn from the supply. The device is protected against short-circuit and over-temperature conditions. The FAN5602 is available with 4.5V and 5.0V output volt- ages in a 3x3mm 8-lead MLP package.

Ordering Information

Note: 1. Reference MLP08D Option B ONLY. Application Diagram Figure 1. Typical Application Diagram

Figure 2. Block Diagram

Figure 3. Pin Assignments 2 C2+ Bucket Capacitor2. Positive Connection. 3 C2- Bucket Capacitor2. Negative Connection.

4 GND Ground

5 C1- Bucket Capacitor1. Negative Connection. OUT Regulated Output Voltage. Bypass this pin with 10μF ceramic low-ESR capacitor. 7 C1+ Bucket Capacitor1. Positive Connection. supply current to less than 1µA. Do not float this pin.

FAN5602 — Universal (Step-Up/Step-Down) Charge Pump Regulated DC/DC Converter © 2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN5602 Rev. 1.5.3 4 Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be opera- ble above the recommended operating conditions and stressing the parts to these levels is not recommended. In addi- tion, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Note: 2. Using Mil Std. 883E, method 3015.7 (Human Body Model) and EIAJ/JESD22C101-A (Charged Device Model). Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Note: 3. Refer to Figure 9 in Typical Performance Characteristics. Symbol Parameter Min. Max. Unit VIN VIN, VOUT, ENABLE, Voltage to GND -3.0 6.0 V Voltage at C1+,C1-,C2+, and C2-to GND -3.0 V IN +0.3 V PD Power Dissipation Internally Limited TL Lead Soldering Temperature (10 seconds) 300 C° TJ Junction Temperature 150 C° TSTG Storage Temperature -55 150 C° ESD Human Body Model (HBM) 2 kV Charged Device Model (CDM) 2 kV Symbol Parameter Condition Min. Typ. Max. Unit VIN Input Voltage 1.8 5.5 V IL Load Current VIN < 2V 30 mA 4.5 & 5.5,VIN = 3.6V 100 TA Ambient Temperature -40 +85 C°

FAN5602 — Universal (Step-Up/Step-Down) Charge Pump Regulated DC/DC Converter © 2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN5602 Rev. 1.5.3 5 VIN = 2.7V to 5.5V, C1 = C2 = 1µF, CIN = COUT = 10µF, ENABLE = VIN, TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C. Symbol Parameter Condition Min. Typ. Max. Unit VUVLO Input Under-Voltage Lockout 1.5 1.7 2.2 v VOUT Output Voltage VIN ≥ 0.75 x VNOM, 0mA < ILOAD <100mA 0.97 x VNOM VNOM 1.03 x VNOM V IQ Quiescent Current VIN ≥ 1.1 x VNOM, ILOAD = 0mA 170 300 µA Off Mode Supply Current ENABLE = GND 0.1 1.0 µA Output Short-Circuit V OUT < 150mV 200 mA Efficiency VIN = 0.85 x VNOM, ILOAD = 30mA 4.5, 5.0V 80 VIN = 1.1 x VNOM, ILOAD = 30mA 4.5, 5.0V 92 fOSC Oscillator Frequency T A = 25°C 0.7 1.0 1.3 MHz TSD Thermal Shutdown Threshold 145 °C TSDHYS Thermal Shutdown Threshold Hysteresis 15 °C V IH ENABLE Logic Input High Voltage 1.5 V VIL ENABLE Logic Input Low Voltage 0.5 V IEN ENABLE Logic Input Bias Current ENABLE =V IN or GND -1 1 µA tON VOUT Turn-On Time VIN = 0.9 x VNOM, ILOAD = 0mA,10% to 90% 0.5 ms VOUT Ripple V IN = 2.5V, ILOAD = 200mA 10 mVpp

FAN5602 — Universal (Step-Up/Step-Down) Charge Pump Regulated DC/DC Converter © 2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN5602 Rev. 1.5.3 9 Functional Description FAN5602 is a high-efficiency, low-noise switched capaci- tor DC/DC converter capable of step-up and step-down operations. It has seven built-in switch configurations. Based on the ratio of the input voltage to the output volt- age, the FAN5602 automatically reconfigures the switch to achieve the highest efficiency. The regulation of the output is achieved by a linear regulation loop, which modulates the on-resistance of the power transistors so that the amount of charge transferred from the input to the flying capacitor at each clock cycle is controlled and is equal to the charge needed by the load. The current spike is reduced to minimum. At light load, the FAN5602 automatically switches to Pulse Frequency Modulation (PFM) mode to save power. The regulation at PFM mode is achieved by skipping pulses. Linear Regulation Loop The FAN5602 operates at constant frequency at load higher than 10mA. The linear regulation loop consisting of power transistors, feedback (resistor divider), and error amplifier is used to realize the regulation of the out- put voltage and to reduce the current spike. The error amplifier takes feedback and reference as inputs and generates the error voltage signal. The error voltage sig- nal is then used as the gate voltage of the power transis- tor and modulates the on-resistance of the power transistor and, therefore, the charge transferred from the input to the output is controlled and the regulation of the output is realized. Since the charge transfer is controlled, the FAN5602 has a small ESR spike. Switch Array Switch Configurations The FAN5602 has seven built-in switch configurations, including 1:1, 3:2, 2:1 and 3:1 for step-down and 2:3, 1:2 and 1:3 for step-up. When 1.5 x V OUT > V IN > V OUT, the 1:1 mode shown in Figure 21 is used. In this mode, the internal oscillator is turned off. The power transistors connecting the input and the output become pass transistors and their gate voltages are controlled by the linear regulation loop, the rest of power transistors are turned off. In this mode, the FAN5602 operates exactly like a low dropout (LDO) regu- lator and the ripple of the output is in the micro-volt range. When 1.5 x V IN > V OUT > V IN, the 2:3 mode (step-up) shown in Figure 22 is used. In the charging phase, two flying capacitors are placed in series and each capacitor is charged to a half of the input voltage. In pumping phase, the flying capacitors are placed in parallel. The input is connected to the bottom the capacitors so that the top of the capacitors is boosted to a voltage that equals VIN/2 + VIN, i.e., 3/2 x VIN. By connecting the top of the capacitors to the output, one can ideally charge the output to 3/2 x V IN. If 3/2 x V IN is higher than the needed VOUT, the linear regulation loop adjusts the on- resistance to drop some voltage. Boosting the voltage of the top of the capacitors to 3/2 x V IN by connecting V IN the bottom of the capacitors, boosts the power efficiency 3/2 times. In 2:3 mode, the ideal power efficiency is V OUT/1.5 x VIN. For example, if VIN = 2V, VOUT = 2 x VIN = 4V, the ideal power efficiency is 100%. When 2 x VIN > VOUT > 1.5 x VIN, the 1:2 mode (step-up) shown in Figure 23 is used. Both in the charging phase and in pumping phase, two flying capacitors are placed in parallel. In charging phase, the capacitors are charged to the input voltage. In the pumping phase, the input volt- age is placed to the bottom of the capacitors. The top of the capacitors is boosted to 2 x V IN. By connecting the top of the capacitors to the output, one can ideally charge the output to 2 x VIN. Boosting the voltage on the top of the capacitors to 2V IN boosts the power efficiency 2 times. In 1:2 mode, the ideal power efficiency is VOUT/2 x VIN. For example, V IN = 2V, VOUT = 2 x V IN = 4V, the ideal power efficiency is 100%. When 3 x V IN > VOUT > 2 x V IN, the 1:3 mode (step-up) shown in Figure 24 is used. In charging phase, two flying capacitors are placed in parallel and each is charged to VIN. In the pumping phase, the two flying capacitors are placed in series and the input is connected to the bottom of the series connected capacitors. The top of the series connected capacitors is boosted to 3 x V IN. The ideal power efficiency is boosted 3 times and is equal to VOUT/ 3VIN. For example, V IN = 1V, V OUT = 3 x V IN = 3V, the ideal power efficiency is 100%. By connecting the output to the top of the series connected capacitors, one can charge the output to 3 x VIN. The internal logic in the FAN5602 monitors the input and the output compares them, and automatically selects the switch configuration to achieve the highest efficiency. The step-down modes 3:2, 2:1, and 3:1 can be under- stood by reversing the function of V IN and V OUT in the above discussion. The built-in modes improve power efficiency and extend the battery life. For example, if V OUT = 5V, mode 1:2 needs a minimum V IN = 2.5V. By built-in 1:3 mode, the minimum battery voltage is extended to 1.7V.

FAN5602 — Universal (Step-Up/Step-Down) Charge Pump Regulated DC/DC Converter © 2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN5602 Rev. 1.5.3 11

Application Information

Using the FAN5602 to Drive LCD Backlighting The FAN5602 4.5V option is ideal for driving the back- lighting and flash LEDs for portable devices. One FAN5602 device can supply the roughly 150mA needed to power both the backlight and the flash LEDs. Even though drawing this much current from the FAN5602 drives the part out of the 3% output regulation, it is not a problem. The backlight and flash LEDs still produce opti- mal brightness at the reduced regulation. When building this circuit, use ceramic capacitors with low ESR. All capacitors should be placed as close as possible to the FAN5602 in the PCB layout. Figure 25. Circuit for Backlighting / Flash Application

Figure 26. 8-Lead, 3x3mm, Molded Leadless Package (MLP), .8mm Thick specifically the warranty therein, which covers Fairchild products. http://www.fairchildsemi.com/packaging/.

FAN5602 — Universal (Step-Up/Step-Down) Charge Pump Regulated DC/DC Converter © 2005 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN5602 Rev. 1.5.3 13