PS0100 600mA Synchronous Boost Converter with Output Disconnect FEATURES Up to 92% efficiency Low start-up voltage 0.8V Internal synchronous rectifier Up to 2MHz switching allows for tiny external components 0.5V to 4.4V input range 2.5V to 5.0V output range (Note 3) Fully discharged shutdown output voltage Logic controlled shutdown (<1µA) Low 250µA operating supply current (measured at VOUT) Pulse skipping at light load for extended battery life Generates 3.3V at 100mA from single AA cell Stable with ceramic output capacitor Low profile 6-Leads SOT-26 package APPLICATIONS DESCRIPTION The PS0100 is a synchronous, step-up DC/DC converter delivering high efficiency in a SOT-26 package. The device has an internal NMOS switch and PMOS synchronous rectifier and has the capacity of supplying 3.3V at 100mA from a single AA cell input. High frequency switching (up to 2MHz) minimizes the board area by allowing the use of tiny, low profile inductors and ceramic capacitors. The PS0100 provides automatic pulse skipping at light loads, thus reducing the supply current for extended battery life. At shutdown, the PS0100 fully discharges the output to ground and draws no supply current. The PS0100 is available in small SOT-26 package with both fixed and adjustable output voltage versions. MP3 / MP4 players PDAs and organizers Digital cameras Wireless mice/ keyboards Portable medical equipment Cordless phones Wireless Headsets TYPICAL APPLICATION CIRCUIT July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 1 PS0100 PIN CONFIGURATION PIN DESIGNATOR Name Pin SW 1 GND 2 FB 3 SHUTB 4 VOUT 5 VIN 6 Type Switch Ground Feedback Shutdown input Analog output Battery input Function Connects inductor between SW and VIN Ground pin Adjustable feedback input, connects to resistor voltage divider SHUTB = High: normal operation (Supports both TTL and CMOS logic) Boost regulator output Boost regulator input ORDERING INFORMATION Part Number PS0100A PS0100 – 2.5 PS0100 – 2.8 PS0100 – 3.0 PS0100 – 3.3 July 2007 Voltage Adj. 2.5 2.8 3.0 3.3 Junction Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C www.picsemi.com © 2007 Power IC. All Rights Reserved. Package SOT-26 SOT-26 SOT-26 SOT-26 SOT-26 2 PS0100 BLOCK DIAGRAM SW VIN Discharge Switch Body Manage Switch VOUT Bias Select + - Bias to all Circuitry Current Sense Amplifier Zero-Current Ref + Thermal Sensor - Zero Crossing Comparator + - Gate Control Logic Program Voltage Fixed TON + - Over-Current Limiter Time Control Logic Start-up Oscillator Minimum TOFF UVLOB Under Voltage Lockout REFERENCE SHUTB Shut-Down Circuitry REF + _ FB Shut Down GND July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 3 PS0100 ABSOLUTE MAXIMUM RATINGS Symbol VIN VSW VSHUTB VFB VOUT ISW, IOUT, IGND TSTG RθJA TA, MAX TL ESD Parameter DC Supply Voltage at Pin 6 SW Voltage - DC SW Voltage–Pulsed (<100nS) SHUTB Voltage FB Voltage Output Voltage Switch Current Storage Temperature Range Thermal Resistance, Junction-To-Air Operating Temperature Range (Note 4) Lead Temperature (Soldering, 10sec) ESD Capability, HBM model Value -0.3 to 6.0 -0.3 to 6.0 -0.3 to 7.0 -0.3 to 6.0 -0.3 to 6.0 -0.3 to 6.0 0 to 1A -65 to +125 N/A -40 to +85 260 2.0 Unit V V V V V V A °C °C/W °C °C KV ELECTRICAL CHARACTERISTICS (All specifications are at TA = 25°C, VIN = 1.5V, VOUT = 3.3V, VSHUTB = 1.5V, unless otherwise specified.) Parameter Minimum Start-Up Voltage Minimum Operating Voltage Maximum Input Operating Voltage Output Voltage Adjust Range Feedback Voltage Feedback Input Current Load Regulation Quiescent Current (No-Switching) Quiescent Current (Shut-down) Conditions No load Note 1 Note 2 Min Note 3 TA = -40°C to 85°C (Note 4) VFB = 1.2V ILOAD = 10mA to 100mA VFB = 1.2V, measured at VOUT 2.5 0.97 Typ 0.8 0.5 4.4 1.0 1 2.2 250 Max 0.95 Unit V V V 5.0 1.03 420 V V nA % µA 1 µA 0.01 NMOS Switch On Resistance VSHUTB = 0V, VOUT = 0V, including switch leakage VOUT = 3.3V 0.45 Ω PMOS Switch On Resistance VOUT = 3.3V 0.6 Ω NMOS Current Limit PMOS Turn-Off Current Current Limit Delay to Output Minimum Off-Time Maximum On-Time Maximum On-Time to Minimum Off-Time Ratio July 2007 600 VIN = 0.5V VFB = 0.95V, VIN = 0.5V, TA = -40°C to 85°C (Note 4) www.picsemi.com © 2007 Power IC. All Rights Reserved. 0.6 4 50 100 0.13 0.95 7.3 1.4 mA mA nS µS µS 4 PS0100 ELECTRICAL CHARACTERISTICS (continued) (All specifications are at TA = 25°C, VIN = 1.5V, VOUT = 3.3V, VSHUTB = 1.5V, unless otherwise specified.) Parameter SHUTB Input High SHUTB Input Low SHUTB Input Current Frequency at Start-Up Thermal Shutdown Conditions Min 0.95 Type Max 0.35 100 15°C Hysteresis 650 145 Unit V V nA KHz °C Note 1: Minimum operating input voltage is fixed by the battery’s ability to provide necessary power at that (terminal) voltage. Below this voltage, the battery fails to deliver required power as it enters into deeply discharged state. This voltage can be lower if the required duty cycle is less. Note 2: When the input voltage is greater than the output voltage regulation point, the part operates in track mode (see Track Mode). Note 3: For applications where VOUT > 4.3V, an external Schottky diode is recommended. Note 4: Limits are 100% production tested at TA=25°C. Specifications over the -40°C to +85°C operating temperature range are assured by design. July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 5 PS0100 TYPICAL OPERATING CHARACTERISTICS (All specifications are at TA =+25°C, VIN = 1.5V, circuit of typical application circuit, unless otherwise specified.) July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 6 PS0100 TYPICAL OPERATING CHARACTERISTICS (continued) July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 7 PS0100 TYPICAL OPERATING CHARACTERISTICS (continued) July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 8 PS0100 TYPICAL OPERATING CHARACTERISTICS (continued) July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 9 PS0100 OPERATION The PS0100 is a compact, high-efficiency, synchronous boost converter in a SOT-26 package designed for spacerestricted applications. The part is available with adjustable output voltages ranging from 2.5V to 5.0V. It is able to start up with input voltages as low as 0.8V and operate with input voltages down to 0.5V. With its internal synchronous rectifier and low on-resistance of the internal NMOS switch, the device maintains high efficiency over a wide range of load current. As shown in the Block Diagram, the PS0100 consists of accurate band gap core, error amplifier, start-up oscillator and control logic unit along with PMOS and NMOS switches. With current mode PWM control, the PS0100 has ultra-fast line and improved load regulation. Moreover, the PS0100 provides real shutdown circuitry which disconnects the output from the input during shutdown and results in the discharge of the output to ground. Start-Up Mode The PS0100 starts up typically at 0.8V. When it is turned on, the device gets its start up bias from VIN. A start-up oscillator, which runs typically at 650 KHz, takes the output voltage high enough so that VOUT exceeds VIN. Once VOUT exceeds VIN, the internal bias switches from VIN to VOUT by an internal bias-select circuit. Thus, once started (i.e. VOUT exceeds VIN), the internal circuit bias is completely independent of VIN. The start-up oscillator runs at 66% duty cycle at around 650KHz. Once VOUT exceeds VIN (typically 1.9V), the start-up oscillator is disabled and the normal fixed TON PWM operation takes over. Internal PMOS and NMOS Switches The PS0100 features a 0.45Ω NMOS switch and a 0.6Ω PMOS switch. In normal operation, these switches are alternatively turned on and thus initiate the charging of the inductor from VIN and then discharging of it to the output capacitor and the load. However, between the event of one switch turning off and the other turning on, a dead time is provided to avoid a huge in-rush current from the output to ground via switches. During the dead time, both switches remain off and the inductor discharges via the body diode of the PMOS switch to the output. True Shutdown Mode The PS0100 is designed to allow for true shutdown by managing the body diode of the PMOS switch. As the PMOS switch is turned off and there is no July 2007 conductive path through the body of the PMOS, the output is allowed to go to zero during shutdown, drawing zero current from the input. Output Voltage Selection The PS0100 features a user-adjustable output through an external feedback network. A voltage divider from VOUT to ground programs the output voltage via FB from 2.5V to 5V using the following equation: VOUT = VREF × [1 + (R1/R2)] where, VREF = 1.0V Thermal Overload Protection Thermal overload protection limits the total power dissipation in the PS0100. When the junction temperature exceeds TJ = +145°C, the thermal sensor signals the shutdown logic and turns off most of the internal circuitry. The thermal sensor turns the internal circuitry on again after the IC’s junction temperature drops by 15°C. Thermal overload protection is designed to protect the PS0100 in the event of a fault condition. For continuous operation, do not exceed the absolute maximum junction temperature rating of TJ = +125°C. Current Limit and Short Circuit Protection The PS0100 includes a current limiter that monitors the peak inductor current through the NMOS switch and turns the NMOS switch off when the inductor peak current exceeds 850mA. Because of its true shutdown feature, the IC is allowed to be short-circuited. The thermal shutdown turns off the regulator in the event of excessive heating when the die temperature reaches 145°C. Light Load Operation The PS0100 provides improved light load efficiency. The internal zero current comparator monitors the inductor current to the load and shuts off the PMOS switch once this current reduces to some low value (typically 50mA). This prevents the inductor current from reversing its polarity, avoiding back-charging and thus improving the efficiency at light loads. At that time, both the NMOS and PMOS switches remain off. However, normal operation starts again when the output voltage falls below the regulation point. The IC automatically skips pulses at light load, thus providing better efficiency. www.picsemi.com © 2007 Power IC. All Rights Reserved. 10 PS0100 Enable Input Anti-Ringing Control When the inductor current goes to zero, there arises a high frequency ringing at the SW pin. To prevent this, a 100Ω discharge switch is provided between SW and VIN, so that this high frequency ringing is damped out. Under Voltage Lockout When the supply becomes too low (typically below 1.8V), the PS0100 produces an internal UVLO (Under Voltage Lockout) signal that disables the normal PWM operation and enables the start-up oscillator to run at a fixed frequency. At this stage, very few circuits are operational. When the oscillator raises the supply to above 1.9V, the UVLO signal is disabled and the normal PWM mode takes over the operation of the start-up oscillator. This mechanism protects the chip from producing false logic due to low input supply. July 2007 The PS0100 features an active-high CMOS input enable pin (SHUTB) that allows on/off control of the regulator. When SHUTB=Low, shutdown of the chip occurs and at that time almost no quiescent current (<1µA) flows. The output capacitor can be completely discharged through the load or the feedback resistors for real output shutdown. A discharge switch is internally connected between VIN and SW. The Enable (SHUTB) input is TTL/CMOS compatible. Connect SHUTB to VIN for normal operation. Track Mode The PS0100 is in track mode when VIN is greater than the output voltage regulation point. In track mode, the regulator runs at a fixed start-up oscillator frequency. The start-up oscillator runs freely until VOUT exceeds VIN. When VOUT falls below VIN, the start-up oscillator is enabled again. Thus, in track mode, the regular loop control of PWM operation remains off. Instead, the regulator runs by intermittent oscillator operation. www.picsemi.com © 2007 Power IC. All Rights Reserved. 11 PS0100 PACKAGE INFORMATION July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 12 PS0100 DISCLAIMERS LIFE SUPPORT Power IC’s products are NOT designed to be used as components in devices intended to support or sustain human life. The use of Power IC’s products in components intended for surgical implants into the body or other applications, in which failure of Power IC’s products could create a situation where personal death or injury may occur, is NOT authorized without the express written approval of Power IC’s Chief Executive Officer. Power IC will NOT be held liable for any damages or claims resulting from the use of its products in medical applications. MILITARY Power IC’s products are NOT designed for use in military applications. The use of Power IC’s products in military applications is NOT authorized without the express written approval of Power IC’s Chief Executive Officer. Power IC will NOT be held liable for any damages or claims resulting from the use of its products in military applications. RIGHT TO MAKE CHANGES Power IC reserves the right to change this document and/or this product without notice. Customers are advised to consult their Power IC sales representative before ordering. July 2007 www.picsemi.com © 2007 Power IC. All Rights Reserved. 13