HIP6200, HIP6201 Data Sheet Transient Voltage Regulator DeCAPitator™ February 1998 File Number 4423.2 Features The Intersil DeCAPitator helps to stabilize a power system voltage during severe transients. It accomplishes this by supplying current when the voltage is more than 1% low or sinking current when the voltage is higher than 1.5% from the average load voltage. The fast transient response of the DeCAPitator can make up for the slow response time of many switching DC-DC converters. Although the HIP6200 serves as a simple replacement for large output capacitors for any dynamic load, it is especially useful in stabilizing the CPU core voltage in portable computer applications, where size and efficiency are major concerns. The DeCAPitator enables power supply designs for more powerful microprocessors without increasing converter size or decreasing converter efficiency. The DeCAPitator acts independently of the PWM control circuitry. This simplifies converter layout because the DeCAPitator and the load may be located separately from the DC-DC converter. The DeCAPitator should be located near the load for optimum performance. • Saves Power System Size and Cost - Replaces Expensive Bulk Capacitors - Small 8 Lead SOIC Package • Linear Regulator Response - Greater than 5MHz Bandwidth • Very Low Static Power Dissipation - Shutdown Current . . . . . . . . . . . . . . . . . . . . . . . . . < 5µA - Power Dissipated Only During Load Transients • Over Temperature Shutdown/Signal • Simplifies Power Supply Layout - Allows for Remotely Located CPU DC-DC Converter Applications • Notebook Computers • Pentium®, Pentium Pro, and Pentium II Power Supplies Ordering Information PART NUMBER TEMP. RANGE (oC) PACKAGE PKG. NO. HIP6200CB 0 to 70 8 Ld SOIC M8.15 HIP6201CB 0 to 70 8 Ld SOIC M8.15 Pinouts HIP6200 (SOIC) TOP VIEW HIP6201 (SOIC) TOP VIEW PVCC 1 8 EN/OT PVCC 1 8 EN PGND 2 7 OUT PGND 2 7 OUT GND 3 6 SNS GND 3 6 SNS VCC 4 5 CAP VCC 4 5 CAP Pentium® is a registered trademark of Intel Corporation. DeCAPitator™ is a trademark of Intersil Corporation. 2-441 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999 HIP6200, HIP6201 Typical Application - Portable CPU Dynamic Regulator PWM CONTROLLER BATTERY POWER +5V VCC 4 EN/OT 8 HIP6200 POR 1 PVCC 7 OUT 6 SNS + - X 0.99 R CAP 5 20R CPU LOAD + X 1.015 - 2 3 PGND GND Block Diagram VCC PVCC RVCC EN/OT (HIP6200) THERMAL MONITOR (TMON) POWER-ON RESET (POR) EN (HIP6201) 99% UPPER COMPARATOR + - ENABLE + UPPER AMPLIFIER - OUT RT1 SNS CAP RT2 LOWER AMPLIFIER ROUT + + 101.5% ENABLE RGND LOWER COMPARATOR GND 2-442 PGND HIP6200, HIP6201 Functional Pin Description PVCC (Pin 1) PVCC is the power source for the npn transistor output device. PVCC is connected internally to VCC through a resistor. Bulk capacitance should be placed between this pin and PGND to minimize voltage deviations. PGND (Pin 2) PGND is power ground for the N-Channel MOSFET output device. Tie this pin to the ground plane of the circuit board. GND (Pin 3) GND is signal ground for the IC. Tie this pin to the ground plane of the circuit board. VCC (Pin 4) VCC provides bias power to the chip. It should be tied to system 5V. Provide local decoupling to this pin. CAP (Pin 5) Connect a capacitor to GND to set the internal amplifiers’ on-time response to a rapid voltage change at the SNS pin. SNS (Pin 6) SNS is the remote sense of the output voltage to be regulated. If the output voltage increases rapidly by greater than 1.5%, the lower amplifier responds by turning on the NChannel MOSFET to sink current through the OUT pin to PGND. If the output voltage decreases rapidly by greater than 1%, the upper amplifier responds by turning on the npn transistor to source current from PVCC to OUT. OUT (Pin 7) This pin is the output pin of the IC. Tie this pin directly to the voltage to be regulated. EN/OT or EN (Pin 8) This pin is the only differentiation between the HIP6200 and the HIP6201. On the HIP6200, this pin is multiplexed. It is chip enable and also an overtemperature indicator. When this pin is low, the chip is disabled. If an overtemperature occurs, this pin will be pulled low internally. Tie EN/OT to a pull-up resistor and drive with an open collector signal. On the HIP6201, this pin is chip enable only. Pulling it low disables the IC. EN should be driven with a logic signal. 2-443 HIP6200, HIP6201 Absolute Maximum Ratings Thermal Information Supply Voltage, VCC, PVCC . . . . . . . . . . . . . . . . . . . . . . . . . . . +7.0V EN, CAP, OUT, SNS. . . . . . . . . . . . . . . . . . . . . . . .GND-0.3V to +7V GND - PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to +0.5V Thermal Resistance (Typical, Note 1) θJA (oC/W) SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145oC/W Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC (SOIC - Lead Tips Only) Operating Conditions Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +5V ±5% Output Device Supply Voltage, PVCC . . . . . . . . . . . . +4.5V to +5.5V Output Voltage, OUT = SNS = CAP. . . . . . . . . . . . . . +1.3V to +2.0V Load Transient Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±8A Ambient Operating Temperature Range . . . . . . . . . . . . 0oC to 70oC Junction Temperature Range . . . . . . . . . . . . . . . . . . . . 0oC to 125oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications PARAMETER Recommended Operating Conditions, Unless Otherwise Noted SYMBOL TEST CONDITIONS MIN TYP MAX UNITS - 300 - µA - 1 - µA 0.8 1.5 2.0 V VCC SUPPLY CURRENT Nominal Supply IVCC Shutdown Supply IVCC_SD EN = GND PROTECTION CIRCUITRY EN Threshold VTH_EN Overtemperature (OT) Threshold On-Resistance of OT NMOS OT 130 150 170 oC Rds_TFN - 250 600 Ω POWER-ON RESET (POR) VCC Rising Threshold VTHH_VCC EN = VCC - 4.1 4.5 V VCC Falling Threshold VTHL_VCC EN = VCC 3.6 4.0 - V CAP Rising Threshold VTH_CAP EN = VCC - 1.10 1.20 V EN = VCC 0.95 1.05 - V CAP Falling Threshold POR Turn-Off Delay to EN Falling - 2 - µs POR Turn-On Delay to EN Rising - 1 - ms POR Turn-Off Delay to VCC UV EN = VCC, VCC Falling - 15 - µs POR Turn-On Delay after VCC UV EN = VCC, VCC Rising - 15 - µs POR Turn-Off Delay to CAP UV EN = VCC, CAP Falling - 2 - µs POR Turn-On Delay after CAP UV EN = VCC, CAP Rising - 15 - µs REFERENCE VOLTAGE VSNS - VCAP VHIGH CAP = 2V, SNS Increased Until Amplifier Turns On - 30 - mV VCAP - VSNS VLOW CAP = 2V, SNS Decreased Until Amplifier Turns On - 20 - mV - 500 - A/V AMPLIFIERS Transconductance Response Time (Rising) 60mV Step on OUT, Time for IOUT < -4A 50 100 175 ns Response Time (Falling) -60mV Step on OUT, Time for IOUT > 4A 50 100 175 ns RESISTOR VALUES Small Time Constant Resistor RT1 120 200 250 Ω Large Time Constant Resistor RT2 3000 4000 5500 Ω VCC to PVCC Resistor RVCC 6 10 16 Ω OUT to SNS Resistor ROUT 1000 1500 2100 Ω GND to PGND Resistors RGND - 140 - Ω 2-444 HIP6200, HIP6201 Application Information maintain a small difference between the desired and actual output voltage. Theory of Operation The HIP6200 is used in conjunction with a switching DC-DC converter to provide a regulated DC voltage. The output voltage of a DC-DC converter changes instantly with sudden load changes characteristic of today’s microprocessors. This change occurs because the bulk capacitors are imperfect; they have parasitic resistances (ESR) and inductances (ESL) which translate into voltage drops as the load is initially supplied by the bulk capacitance. Also, due to its output inductor, the DC-DC converter takes about 10-20µs (typical) before it provides the load current required by the CPU. The HIP6200 contains two high-speed linear regulators which are inactive except during the converter response time after high di/dt load transients. When active, the linear regulators The Typical Application Diagrams below illustrate how the DeCAPitator functions. The left side shows a common DCDC converter response to a fast ‘low-to-high’ load transient. The right side shows a similar response with a HIP6200 circuit employed. The HIP6200 allows the use of fewer bulk capacitors to handle the regulation requirements of the high edge-rate load transients. The response time of the HIP6200’s linear regulators (100ns typical) are fast enough to help with the leading edge spike. Output voltage deviations during the converter response time are reduced with the HIP6200 since it helps supply the load while the inductor current slews. Typical Application Diagrams PWM CONTROLLER BATTERY POWER IL +5V BATTERY POWER PVCC VCC VOUT EN 8 ICPU PWM CONTROLLER 7 HIP6201 VCAP IL CBULK CAP 5 CBULK: (11) 220µF, 10V, 0.1Ω Tantalums CCAP GND 2 OUT VOUT IOUT 6 3 CPU LOAD CPVCC 1 4 SNS ICPU PGND CPU LOAD CBULK CBULK: (5) 100µF, 10V, 0.1Ω Tantalums CCAP: small Ceramic (0805) CVCC: small Ceramic (0805) CPVCC: (1) 100µF, 10V, 0.1Ω Tantalum ICPU ICPU IL IL VCAP VOUT VOUT IOUT CONVERTER RESPONSE TIME (TR) FIGURE 1. PORTABLE CPU WITHOUT HIP6200, HIP6201 2-445 FIGURE 2. PORTABLE CPU WITH HIP6200, HIP6201 HIP6200, HIP6201 Detailed Functional Description As shown in the Block Diagram, the HIP6200 has two comparators which compare the voltage on the CAP pin to the voltage on the SNS pin. The CAP voltage follows the SNS voltage with an R-C delay which is user programmable and also variable depending upon the state of the amplifiers. Normally, resistor RT1 is in parallel with RT2 when the amplifiers are not active. RT1 is small and the CAP voltage (VCAP) follows the SNS voltage (VSNS) closely. During a transient, when either amplifier is active, the switch in series with RT1 opens and RT2 alone (with the capacitor on CAP) sets the time constant. Since RT2 is 20 times larger than RT1, the DeCAPitator has time to source or sink current as the inductor current slews. The CAP voltage waveform is depicted in the Typical Application Diagrams. Prior to the load transient, VCAP follows VOUT (and likewise VSNS) closely. This is important in many portable applications because the DC-DC converter will be in an energy-saving skip-cycle mode at light load currents. In this mode, the output voltage ripple may be in excess of ±2% and could trip the HIP6200’s comparators if VCAP did not track VSNS. This would turn on the amplifiers and waste power. When a fast load transient occurs, VCAP no longer follows VOUT and the DeCAPitator becomes active when VOUT exceeds +1% or -1.5% of VCAP. When the DeCAPitator is active, it either supplies current from the PVCC pin or sources current to PGND. Because of this, a high-quality capacitor must be placed locally from PVCC to GND. The system 5V bus typically has a good deal of bulk capacitance as well as high frequency decoupling sprinkled across the application board. PVCC is tied to the system 5V bus through an on-chip 10Ω resistor. This resistor helps isolate the system 5V from the disturbances on PVCC. The HIP6200 has a power-on reset function which ensures that both VCC and CAP are at some minimum levels before allowing amplifier operation. There is also an EN(ABLE) pin, allowing users to disable the HIP6200 if desired. An overtemperature (OT) shutdown feature ensures that the HIP6200 will not self-destruct from thermal overload. An OT event will shutdown the chip until the junction temperature decreases a few degrees below its trip point. The DeCAPitator draws very little bias current (300µA typical) when its amplifiers are inactive. When either amplifier is active, the chip draws 15-30mA of bias current. This current is mainly for the active high-speed amplifier and lasts only for the duration of the on-time of the HIP6200. Component Selection Guidelines Bulk Output Capacitors For a given converter design without the HIP6200 in the target application, the number of output capacitors is determined mainly by the output voltage regulation and 2-446 transient specifications. It is estimated that for a load transient of 0-8A with a di/dt of 20A/µs, eleven 220µF, 0.1Ω low ESR tantalum capacitors are necessary to maintain CPU core voltage regulation specifications. For identical conditions with a HIP6200 employed, only five 100µF, 0.1Ω low ESR tantalums are required. Similar savings in output capacitance can be achieved with other capacitor dielectrictypes. The number of capacitors which can be eliminated on the output is limited by either of the following: 1. Output voltage ripple - this increases proportional to the equivalent ESR of the bulk output capacitance. This may be counteracted by increasing the output inductance. In many cases the inductor can remain the same because the output ripple will still be acceptably small. 2. Leading edge voltage spike - this may increase with reduced number of capacitors. The HIP6200 and its very fast response is very effective in handling this leading edge spike up to a point. Some additional ceramic decoupling on the OUT pin can also help. PVCC Capacitor A 100µF, 0.1Ω tantalum is recommended on the PVCC pin for an application which has 8A transients (maximum recommended operation of the HIP6200). RVCC is an internal 10Ω resistor from VCC to PVCC which decouples the PVCC transient from the system 5V (VCC). CAP Capacitor The capacitor on the CAP pin sets the amount of time that the HIP6200 has to sink or source current in response to a load transient. The DeCAPitator on-time should be greater than the converter response time. When the HIP6200’s amplifiers are not active, the CAP pin follows the output voltage closely to prevent false tripping at light loads due to PWM skip-cycle modes of operation. These two boundaries are addressed with RT1 and RT2 internal to the HIP6200 but must also be verified on each design. The converter response time is the time interval required for the inductor current to slew to the output load current. This time is dramatically different for the two edges of the transient event if there is a large differential between input and output voltages of the converter. The converter response times are approximated by v = L*di/dt: I STEP T R1 = L OUT • -----------------------------------( V IN – V OUT ) (EQ. 1) I STEP T R2 = L OUT • -------------------( V OUT ) (EQ. 2) where TR1 = converter response time to low-to-high load transient TR2 = converter response time to high-to-low load transient HIP6200, HIP6201 LOUT = output inductor value and: ISTEP = transient current step amplitude Ibias UP • t ACTIVE Ibias DWN • t ACTIVE I BIAS = I IDLE + --------------------------------------------------- + -------------------------------------------------------T T The value of the capacitor at the CAP pin should be sized so that the HIP6200 can be active in response to a transient for longer than the greater of TR1 and TR2. For a 12V to 1.7V DC-DC converter with a 3µH inductor and a 8A maximum transient step size, TR1 = 2.3µs and TR2 = 14.1µs. Thus, the CAP capacitor should be chosen for the worst-case TR2 response. Though the HIP6200 will be active for longer than necessary in response to the low-to-high load transient, the amount of power wasted will be minimal. The upper amplifier will be active, drawing about 15mA, but the power npn darlington will pinch off after the inductor current slews up. The following section details power dissipation further. Thermal Considerations HIP6200 Power Dissipation The power dissipated by the DeCAPitator is a function of many variables. The load transient step size (ISTEP), the frequency of the transient events (1/TTRAN), and the converter response time (TR1, TR2) have the largest influence. Figure 3 displays these terms. TTRAN ICPU ISTEP TRAN TRAN (EQ. 7) IIDLE = nominal supply current when HIP6200 is powered and amplifiers are not active (300µA typical) IbiasUP = upper amplifier bias current when active (15mA typical) IbiasDWN = lower amplifier bias current when active (30mA typical) tACTIVE = time amplifiers are active. This time is set by CAP capacitor and should be at least as long as TR2. The bias power is a very small percentage of the total chip power dissipation, but is included for completeness. Based on these equations, the two figures below show how the power dissipation varies with the transient frequency (1/TTRAN), step load change (ISTEP), and converter response time (TR1, TR2). Both figures assume VIN = 12V and VOUT = 1.7V. Figure 4 assumes a 3µH output inductor and varies the step size (as well as the transient frequency). As mentioned in the previous section, these conditions give TR1 = 2.3µs and TR2 = 14.1µs for ISTEP = 8A. Figure 5 holds ISTEP constant at 8A and varies the response time. The converter response time often differs from the ideal (Equations 1 and 2) substantially and therefore should be verified experimentally. IOUT 0.6 POWER DISSIPATION (W) TR2 TR1 FIGURE 3. IDEALIZED WAVEFORMS OF DeCAPitator OPERATION Based on some simplifying assumptions, the DeCAPitator power dissipation can be approximated as follows: P DISS = P BIAS + P UP + P DWN (EQ. 3) 0.5 ISTEP = 8A 0.4 ISTEP = 4A ISTEP = 6A 0.3 0.2 0.1 102 103 104 105 TRANSIENT FREQUENCY (Hz) where: T R1 I STEP P UP = ( V CC – V OUT ) • ---------------- • ------------------- T TRAN 2 (EQ. 4) T R2 I STEP P DWN = ( V OUT ) • ---------------- • ------------------- T TRAN 2 (EQ. 5) P BIAS = V CC • ( I BIAS ) (EQ. 6) 2-447 FIGURE 4. ESTIMATED HIP6200, HIP6201 POWER DISSIPATION vs ISTEP Figures 4 and 5 show the relationships between the DeCAPitator power dissipation and the load transient frequency, load transient step size and the converter response time. The power dissipation is linear with the transient frequency but is shown on the log scale to emphasize the fact that the HIP6200/1 power is minimal at frequencies below a few hundred Hertz. HIP6200, HIP6201 In actual systems, the load transient will most likely be of varying frequency and step size. The power dissipation of the HIP6200/1 becomes even more difficult to estimate analytically. Example: HIP6200/1 Junction Temperature Calculation TAMBIENT = 70oC PDISS = 0.2W POWER DISSIPATION (W) ΘJA = 100oC/W 0.6 TR1 = 15µs, TR2 = 40µs TR1 = 10µs, TR2 = 30µs 0.5 TR1 = 2µs, TR2 = 10µs THIP6200 = 70oC + (0.2 x 100) = 90oC TR1 = 5µs, TR2 = 20µs In a similar fashion, one could estimate the maximum allowable power dissipation for given maximum ambient and transient loading and determine the boundary of maximum transient frequency. 0.4 0.3 Example 0.2 Maximum Transient Frequency Calculation 0.1 TAMBIENT = 70oC 102 103 104 TRANSIENT FREQUENCY (Hz) FIGURE 5. ESTIMATED HIP6200, HIP6201 POWER DISSIPATION vs CONVERTER RESPONSE TIME HIP6200 Temperature Rise The HIP6200/1 junction temperature can be estimated simply by: T HIP6200 = T AMBIENT + ( P DISS • Θ JA ) (EQ. 8) where: ΘJA is the thermal resistance from junction to ambient. 2-448 THIP6200 = 110oC max ΘJA = 80oC/W (this number is dependent upon airflow and the amount of pc board trace connected to HIP6200 Max PDISS = (110oC - 70oC)/(80oC/W) = 0.5W From Figures 4 and 5, the estimated maximum transient frequency is obtained for any of the seven cases shown. For instance, from Figure 4, the maximum transient frequency is about 4kHz for the 8A transient step and the conditions stipulated. HIP6200, HIP6201 Layout Considerations P5V 4 VCC C37 + 100µ 10V FROM µP CORE + C19-23 5x 100µ 10V 6 C24-26 3x 1µ 16V PVCC EN 8 U3 HIP6201 7 VOUT OUTPUT OF DC-DC (OUTPUT INDUCTOR) 1 OUT CAP C38 0.1µ 5 SNS PGND 2 RTN GND C39 8200p 3 RTN CERAMIC DECOUPLING FOR HIGH di/dt LOAD (MAY NOT BE REQUIRED) BULK OUTPUT CAPACITANCE OF DC-DC CONVERTER FIGURE 6. TYPICAL SCHEMATIC Example Layout • HIP6200 located near bulk output capacitance (not shown is the microprocessor load itself - for best performance, the HIP6200 and bulk output capacitance should be located close to the µP) • C37 (+5V bulk cap) located near the HIP6200 • Solid ground and VOUT planes with numerous via interconnects TOP - SILK SCREEN TOP - COMPONENT SIDE SOLDER SIDE INTERNAL ONE GND NOTE: Internal layers are shown as negatives (white is copper): via connection to copper plane no connection All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. 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