www.fairchildsemi.com FAN5242 Voltage Regulator for IMVP-II Notebook Processors Features Description • • • • • • The FAN5242 provides the power, control and protection for the CPU in Intel IMVP-II notebook PC applications. The IC integrates a PWM controller as well as monitoring and protection circuitry into a single 24 lead QSOP package. It provides high efficiency PWM at maximum load and hysteretic conversion at minimum load, and generates Intel specified load lines in both Performance and Battery Mode. • • • • • • • Powers Intel IMVP-II CPU core 0.600V to 1.750V output voltage range ±1% reference precision over temperature Dynamic VID code change supported 5V to 24V input voltage range Special controls for Battery Mode and Deeper Sleep Mode Meets IMVP-II Load Lines High efficiency at all load currents Active Droop provides correct load lines True differential remote voltage sense Current sense uses MOSFETs Power Good, Over-current, OV, UVLO Space-saving QSOP24 Applications The FAN5242 includes an Intel specified 5-input DAC that adjusts the core PWM output voltage from 600mV to 1.750V in 25mV steps. The DAC setting may be changed during operation, transition occurring in <100µsec. A precision reference, true differential remote sense, and a proprietary architecture with active droop provide excellent static and dynamic core voltage regulation. The FAN5242 includes over-voltage, and over-current protection, and an enable. It is available in a QSOP 24. • Notebook CPUs • Internet appliances Typical Application Vin = 5–24V 13 18 1 19 5 20 7 21 6 23 24 DPRSLPVR VID LINES DPSLP FAN5242 VCORE + 22 15 16 12 17 11 3 PGOOD 10 4 EN 9 14 SS 8 2 GMUXSEL +5Vin REV. 1.0.1 1/24/02 FAN5242 PRODUCT SPECIFICATIONS Pin Assignments AGND VCC PWRGD ENBL FPWM SLP FREQ VID4 VID3 VID2 VID1 VID0 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 PVCC LDRV PGND ISNS SW HDRV BOOT VCORE VCORE ILIM SS VBATT Pin Description Pin Number Pin Function Description 1 AGND Analog Ground. Return path for low power analog circuitry. This pin should be connected to a low impedance system ground plane to minimize ground loops. 2 VCC VCC. Internal IC supply. Connect to system 5V supply, and decouple with a 0.1µF ceramic capacitor. 3 PWRGD Power Good Flag. An open collector output that will be logic LOW if the output voltage is not within ±10% of the nominal output voltage setpoint. 4 ENABLE Output Enable. A logic LOW on this pin will disable the output. An internal current source allows for open collector control. 5 FPWM Forced PWM. A logic HIGH on this pin forces the converter to remain in PWM mode. 6 SLP Sleep Input. A resistor to ground on this pin overrides the VID settings. 7 FREQ Frequency Set. Grounding this pin sets the switching frequency to 300KHz. Attaching it to VCC sets the frequency to 600KHz. 8-12 VID0-4 Voltage Identification Code Inputs. These open collector/TTL compatible inputs will program the output voltage over the range specified in Table 2. Pull-ups are internal to the controller. 13 VBATT Battery Voltage Input. Connect to the main power source. 14 SS Soft Start. 15 ILIM Current Limit. A resistor from this pin to ground sets the over current trip level. VCORE, VCORE Voltage Feedback. Connect these pins to the desired regulation point at the processor for true differential feedback. 18 BOOT Bootstrap. Input supply for high-side MOSFET. 19 HDRV High Side FET Driver. Connect this pin to the gate of an N-channel MOSFET. The trace from this pin to the MOSFET gate should be <0.5". 20 SW High side driver source and low side driver drain switching node. Gate drive return for high side MOSFET, and negative input for low-side MOSFET current sense. 21 ISNS Current Sense. Connect this pin to the SW node through a resistor to sense output current. 22 PGND Power Ground. Return pin for high currents flowing in low-side MOSFET. Connect directly to low-side MOSFET source. 23 LDRV Low Side FET Driver. Connect this pin to the gate of an N-channel MOSFET for synchronous operation. The trace from this pin to the MOSFET gate should be <0.5". 24 PVCC Power VCC. Provides power to drive low-side MOSFET. 16-17 2 Pin Name REV. 1.0.1 1/24/02 PRODUCT SPECIFICATIONS FAN5242 Absolute Maximum Ratings Absolute maximum ratings are the values beyond which the device may be damaged or have its useful life impaired. Functional operation under these conditions is not implied. Parameter Min. Typ. Max. Units VCC Supply Voltage: 6.5 V VBATT 27 V BOOT, SW, HDRV Pins 33 V BOOT to SW 6.5 V All Other Pins –0.3 VCC+0.3 V Junction Temperature (TJ ) –10 150 °C Storage Temperature –65 150 °C 300 °C Lead Soldering Temperature, 10 seconds Recommended Operating Conditions Parameter Conditions Supply Voltage VCC Supply Voltage VBATT Ambient Temperature (TA ) Min. Typ. Max. Units 4.75 5 5.25 V 5 24 V –10 85 °C Electrical Specifications (VCC = 5V, VBATT = 5V–24V, and TA = recommended operating ambient temperature range using circuit of Figure 1 unless otherwise noted.) Parameter Conditions Min. Typ. Max. Units 2.7 3.2 mA Shut-down (ENABLE=0) 6 30 µA Operating 12 20 µA 1 µA Power Supplies VCC Current VBATT Current Operating, CL = 10pF Shut-down (ENABLE=0) UVLO Threshold Rising VCC 4.3 4.65 4.75 V Falling 4.1 4.35 4.45 V per Table 1. Output Voltage VID 0.6 1.75 V Initial Accuracy –1 1 % VID Static Load Regulation –2 2 % VID Regulator / Control Functions Output voltage Error Amplifier Gain 86 Error Amplifier GBW 2.7 MHz 1 V/µS Error Amplifier Slew Rate ILIM Voltage RILIM = 30KΩ 0.89 Over-voltage Threshold 1.9 Over-voltage Protection delay 1.6 Under-voltage Shutdown Disabled during VID code change Under-voltage Delay ENABLE, input threshold Logic LOW Logic HIGH REV. 1.0.1 1/24/02 72 1.2 2 1.95 75 dB 0.91 V 2.0 V 3.2 µS 78 % VID 1.6 µS 1.2 V V 3 FAN5242 PRODUCT SPECIFICATIONS Electrical Specifications(Continued) (VCC = 5V, VBATT = 5V–24V, and TA = recommended operating ambient temperature range using circuit of Figure 1 unless otherwise noted.) Parameter Conditions Min. Typ. Max. Units Output Drivers HDRV Output Resistance LDRV Output Resistance Sourcing 3.8 5 Ω Sinking 1.6 3 Ω Sourcing 3.8 5 Ω Sinking 0.8 1.5 Ω Oscillator Frequency Ramp Amplitude, pk–pk FREQ = HIGH 255 300 345 KHz FREQ = LOW 510 600 690 KHz VBATT = 16V Ramp Offset Ramp Gain Ramp amplitude ------------------------------------------VIN 2 V 0.5 V 125 mV/V Reference, DAC and Soft-Start VID input threshold Logic LOW Logic HIGH VID pull-up current 1.21 1.62 to internal 2.5V reference DAC output accuracy V V µA 12 –1 1 % at start-up, VSS.< 0.5 20 26 32 µA at start-up, 1.75 > VSS.> 0.5 350 500 650 µA SLP Current Source 9.5 10 10.5 µA SLP to VID mode threshold 1.71 1.75 1.78 V 123 127 % VID Falling Edge 77 81 % VID Rising Edge 87 94 % VID 1 µA Soft Start current (ISS) PWRGD VCORE Upper Threshold VCORE Lower Threshold 4 PWRGD Output Low IPWRGD = 4mA Leakage Current VPULLUP = 5V 0.5 V REV. 1.0.1 1/24/02 PRODUCT SPECIFICATIONS FAN5242 Table 1. Output Voltage Programming Codes VID4 VID3 VID2 VID1 VID0 VOUT to CPU 1 1 1 1 1 0.600 1 1 1 1 0 0.625 1 1 1 0 1 0.650 1 1 1 0 0 0.675 1 1 0 1 1 0.700 1 1 0 1 0 0.725 1 1 0 0 1 0.750 1 1 0 0 0 0.775 1 0 1 1 1 0.800 1 0 1 1 0 0.825 1 0 1 0 1 0.850 1 0 1 0 0 0.875 1 0 0 1 1 0.900 1 0 0 1 0 0.925 1 0 0 0 1 0.950 1 0 0 0 0 0.975 0 1 1 1 1 1.000 0 1 1 1 0 1.050 0 1 1 0 1 1.100 0 1 1 0 0 1.150 0 1 0 1 1 1.200 0 1 0 1 0 1.250 0 1 0 0 1 1.300 0 1 0 0 0 1.350 0 0 1 1 1 1.400 0 0 1 1 0 1.450 0 0 1 0 1 1.500 0 0 1 0 0 1.550 0 0 0 1 1 1.600 0 0 0 1 0 1.650 0 0 0 0 1 1.700 0 0 0 0 0 1.750 1 - Logic High or open, 0 = Logic Low REV. 1.0.1 1/24/02 5 FAN5242 PRODUCT SPECIFICATIONS Application Circuit Vin = 5–24V +5Vin + C1-2 C3 D1 R1 +5Vin R2 13 18 1 19 5 20 7 21 6 23 24 15 DPSLP Q1 DPRSLPVR Q3 R3 R4 VID LINES Q2 U1 FAN5242 C4 L1 Q4 Processor @ 17.6A R5 Q5 + Q6 R7 C5-7 22 16 12 17 11 3 10 4 9 14 8 2 Q7 R8 PGOOD EN +3.3V R6 R9 +5Vin C8 C9 GMUXSEL Q8 Figure 1. FAN5242 IMVP-II Application Circuit Table 2. FAN5242 Application Bill of Materials Reference C1-2 C3, C9 C4, C8 C5-7 R1, R6 R2 R3 R4 R5 R7 R8 R9 D1 L1 Q1-3, Q8 Q4 Q5-6 Q7 U1 6 Manufacturer, Part # AVX TPSV686*025#0150 Any Any Panasonic EEFUE0D271R Any Any Any Any Any Any Any Any Fairchild MBRD0520 Coiltronics DR127-1R0 Fairchild FDV301N Fairchild FDS6690A Fairchild FDS6680S Fairchild FDV302P Fairchild FAN5242 Quantity 2 Description 68µF, 25V Tantalum Comments 2 2 3 1µF Ceramic 220nF, Ceramic 270µF, Polymer 2 1 1 1 1 1 1 1 1 10KΩ 117.3KΩ, 1% 698Ω, 1% 2.74KΩ, 1% 5.62KΩ, 1% 10Ω, 1% 1.69KΩ, 1% TBD KΩ, 1% 0.5A, 20V Schottky 1 1.0µH, 16A Inductor R < 2.5mΩ 4 N MOSFET SOT-23 1 30V N MOSFET R = 17mΩ 2 30V N MOSFET w/ Schottky R = 17mΩ 1 P MOSFET SOT-23 1 CPU Controller REV. 1.0.1 1/24/02 PRODUCT SPECIFICATIONS Applications Information Overview The FAN5242 is a high efficiency and high precision DC/DC controller for IMVP-II powered notebooks and other portable applications. It provides the voltage necessary for portable applications’ processor core. The core voltage is programmed with a 5-bit VID. Utilization of both input and output voltage feedback, and summing-mode compensation, allows for fast loop response over a wide range of input and output variations. This scheme has a superior range of output current operation and is free of the light load instabilities typical of current mode. The IC design allows for a minimum size design of magnetics and discrete transistors for minimum cost and space at maximum performance. Active droop on the CPU output also minimizes the number of output capacitors required. Also included are a number of additional features to make design straightforward, including a pin to set the core voltage during Deep Sleep and Deeper Sleep. Power Architecture The power output of the FAN5242 is generated from the unregulated input voltage using synchronous buck converters. Both the high-side and the low-side MOSFET are N-channels to maximize efficiency. FAN5242 Selection of a current-limit resistor must include the tolerance of the current-limit trip point, the MOSFET RDS,on tolerance and temperature coefficient, and the ripple current, in addition to the maximum output current. Example: Maximum DC output current is 18A, and the inductor is 1.0µH at this current. The MOSFETs have a cumulative RDS,on = 8.5mΩ at VGS = 4.5V, and will be running at 100°C, at which its resistance is 30% higher than at 25°C. Peak current is DC output current plus peak ripple current: TV o 4µsec × 1.25V I p k = I DC + ---------- = 18A + ------------------------------------ = 21A 2L 2 × 1µH where T is the maximum period, VO is output voltage, and L is the inductance. The voltage across the MOSFET at this current is V = I pk × R DS,on × TC = 21A × 8.5mΩ × 1.3 = 230mV The current source driving the external resistor is 100µA minimum, so we must use V 230mV R ≥ ---- = ------------------ = 2.39kΩ I 100µA The power output has a pin for setting output overcurrent; two pins for remote voltage-sense feedback; a pin that generates a softstart; and an enable pin that can be used to shutdown the converter. Softstart Timing Loop Description Softstart of the converter is accomplished by attaching a capacitor to the SS pin. The control loop of the FAN5242 uses summing-mode control, and requires no external compensation. The control loop measures the current differentially across its low-side MOSFET, subtracting it from the ground voltage, and subtracts the sum from the reference voltage. In addition, it uses voltage feed-forward to guarantee loop rejection of input voltage variation: the ramp amplitude is varied as a function of the input voltage. Example: To get approximately a 1msec softstart, select a It 10µA × 1msec C = ---- = ------------------------------------ = 10nF V 1V capacitor. Light Load Mode Compensation of the control loop amounts to merely selecting suitable output capacitors. Most selections of common Tantalum capacitors will result in a stable loop with adequate phase margin, as will Oscons or Polycaps. Current Limit The converter senses the voltage across the low-side N-channel MOSFET (from the SW pin to ground) and compares it to the voltage across a resistor from SW to the ISNS pins; it can also use a discrete resistor in series with the low-side MOSFET for precision. If the voltage drop exceeds the setpoint, the softstart capacitor is discharged, forcing the converter to re-softstart. REV. 1.0.1 1/24/02 Because the converter is a synchronous buck, it can operate in two quadrants, which means that the ripple current is a constant independent of the load current. At light loads, this ripple current translates into poor efficiency, since it causes circulating current losses in the MOSFETs. To optimize the efficiency at light loads, then, the FAN5242 switches from normal operation to a special light load when the current is low. Light load occurs when the on-state drain-source voltage is less than about 17mV. In light load mode, the FAN5242 switches from PWM (pulse width modulation) to PFM (pulse frequency modulation), which reduces the gate drive current. It also turns off the low side drive completely, which further saves on gate current; in 7 FAN5242 this mode, the converter operates non-synchronously, using the output schottky. The switch to this mode of operation can be avoided by pulling the FPWM pin to VCC. PRODUCT SPECIFICATIONS The ISNS pin can be quite sensitive to stray capacitance, and so it is important to use a low capacitance switch for the resistor to ground, such as the Fairchild FDV301N shown in the Figure. Setting the Switching Frequency Connecting the FREQ pin to ground sets the switching frequency to 300KHz. Connecting the FREQ pin to VCC sets the switching frequency to 600KHz. Setting the Voltage with SLP Deep Sleep and Deeper Sleep voltages can be set with the SLP pin. When the SLP pin is open, the output voltage of the converter is set by the VID pins. When the SLP pin has a resistor to ground, the output voltage of the converter will be equal to 10µA ✕ R. Thus, the DEEPSLEEP voltage of 1.173V can be obtained by turning on a switch with a 117.3KΩ resistor to ground, and the DEEPERSLEEP voltage of 700mV can be obtained by turning on a switch with a 698Ω resistor to ground. Setting the Load Line with ISNS The load line can be set with a resistor between the switching node of the power MOSFETs and the ISNS pin, and further adjusted with a resistor from the ISNS pin to ground. The schematic of Figure 3 shows how to obtain the nominal Performance Mode load line of 4mV/A, and how to use a switch connected to the GMUXSEL signal to obtain the Battery Mode load line of 3mV/A. 8 Overvoltage Protection When the output voltage of the converter exceeds approximately 120% of nominal, it enters into over-voltage protection, with the goal of protecting the load from damage. In over-voltage protection, the high-side MOSFET is turned off and the low-side MOSFET is turned on, crowbarring the output. Once over-voltage protection is triggered, it remains on until power is recycled. Power good Power good is asserted when the output is within its specified tolerance. ENABLE The ENBL pin does the on/off control. Pulling this pin low turns off the converter. Thermal shutdown If the die temperature of the FAN5242 exceeds safe limits, the IC shuts itself off. UVLO If the input voltages falls below the UVLO threshold, the FAN5242 turns itself off. REV. 1.0.1 1/24/02 PRODUCT SPECIFICATIONS FAN5242 Mechanical Dimensions 24 Lead QSOP Inches Symbol Min. A A1 A2 b c D E e H L N α ccc Millimeters Max. Min. 1.35 1.75 0.1 0.25 1.37 1.57 0.20 0.30 0.19 0.25 8.55 8.74 3.81 3.99 0.635 BSC 0.228 0.016 5.79 0.40 24 1. Dimensioning and tolerancing per ANSI Y14.5M-1982. Max. 0.0532 0.0668 0.0040 0.0098 0.054 0.062 0.008 0.012 0.0075 0.0098 0.337 0.344 0.150 0.157 0.025 BSC 0.244 0.050 Notes: Notes 2. "D" and "E" do not include mold flash. Mold flash or protrusions shall not exceed .006 inch (0.15mm). 3. "L" is the length of terminal for soldering to a substrate. 4. Terminal numbers are shown for reference only. 5 5 24 0° 8° 0° 8° .004 — 0.10 6. Symbol "N" is the maximum number of terminals. 2, 4 2 6.20 1.27 — 5. "b" and "c" dimensions include solder finish thickness. 3 6 D E A H C A1 A2 B e SEATING PLANE –C– α L LEAD COPLANARITY ccc C REV. 1.0.1 1/24/02 9 FAN5242 PRODUCT SPECIFICATIONS Ordering Information Part Number Temperature Range Package Packing FAN5242QSC 0°C to 85°C QSOP-24 Rails FAN5242QSCX 0°C to 85°C QSOP-24 Tape and Reel DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 1/24/02 0.0m 001 Stock#DS30005242 2001 Fairchild Semiconductor Corporation