STEVAL-ISA051V2 STMicroelectronics, STEVAL-ISA051V2 Datasheet
STEVAL-ISA051V2
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STEVAL-ISA051V2 Summary of contents
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Complete DDR2/3 memory power supply controller Features ■ Switching section (VDDQ) – 4 input voltage range – 0.9 V, ±1% voltage reference – 1.8 V (DDR2) or 1.5 V (DDR3) fixed output voltages – 0.9 V ...
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Contents Contents 1 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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PM6670AS 7.3 S3 and S5 power management pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 8 Application information ...
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Typical application circuit 1 Typical application circuit Figure 1. Application circuit VDDQ VDDQ ( ( LDO input) LDO input IN4 IN4 IN4 VTTREF VTTREF OUT3 OUT3 ...
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PM6670AS 2 Pin settings 2.1 Connections Figure 2. Pin connection (through top view) VTTGND VTTGND VTTGND VTTSNS VTTSNS VTTSNS DDRSEL DDRSEL DDRSEL VTTREF VTTREF VTTREF PM6670A PM6670A PM6670A PM6670A PM6675S PM6670AS SGND ...
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Pin settings 2.2 Pin description Table 2. Pin functions N° Pin 1 VTTGND 2 VTTSNS 3 DDRSEL 4 VTTREF 5 SGND 6 AVCC 7 VREF 8 VOSC 9 VSNS 10 MODE 11 COMP 12 DSCG ...
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PM6670AS Table 2. Pin functions (continued) N° Pin 18 VCC 19 CSNS 20 PHASE 21 HGATE 22 BOOT 23 LDOIN 24 VTT +5 V low-side gate driver supply. Bypass with a 100 nF capacitor to PGND. Current Sense Input for ...
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Electrical data 3 Electrical data 3.1 Maximum rating Table 3. Absolute maximum ratings Symbol V AVCC V VCC V PHASE P TOT 1. Free air operating conditions unless otherwise specified. Stresses beyond those listed under “absolute maximum ratings” may cause ...
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PM6670AS 4 Electrical characteristics T = -25 ° °C, VCC = AVCC = +5 V and LDOIN connected to VDDQ output if not A otherwise specified Table 6. Electrical characteristics Symbol Parameter Supply section I Operating current IN ...
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Electrical characteristics Table 6. Electrical characteristics (continued) Symbol Parameter DDR3 VDDQ output voltage V DDR2 VDDQ output voltage VDDQ Feedback accuracy Current limit and zero crossing comparator I CSNS input bias current CSNS Comparator offset Positive current limit threshold Fixed ...
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PM6670AS Table 6. Electrical characteristics (continued) Symbol Parameter VTTREF discharge resistance in non-tracking discharge mode VDDQ Output threshold synchronous for final tracking to non-tracking discharge transition V LDO section TT LDO input bias current in full- I LDOIN,ON on state ...
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Electrical characteristics Table 6. Electrical characteristics (continued) Symbol Parameter Power management section Turn OFF level S3,S5 Turn ON level MODE pin high level threshold V MODE MODE pin low level threshold DDRSEL pin high level threshold DDRSEL pin middle level ...
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PM6670AS 5 Typical operating characteristics Figure 3. Efficiency vs load - 1.5 V and 1.8 V, Vin = 12 V 100 0.001 0.01 0.1 Output current (A) Figure 5. Switching ...
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Typical operating characteristics Figure 9. VDDQ load regulation, 1.8 V, Vin = 12 V 1.860 1.850 1.840 1.830 1.820 1.810 1.800 0.001 0.01 0.1 Output current (A) Figure 11. VTT load regulation, 0.9 V, LDOIN = 1.8 V 0.940 0.930 ...
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PM6670AS Figure 15. Power-up sequence - AVCC above UVLO Figure 17 1.8 A VTT load transient, 0.9 V Typical operating characteristics Figure 16. VDDQ soft-start, 1.8 V, heavy load Figure 18 ...
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Typical operating characteristics Figure 19. Non-tracking (soft) discharge Figure 21 VDDQ load transient, PWM 16/53 Figure 20. Tracking (fast) discharge, LDOIN = VDDQ Figure 22 VDDQ load transient, PWM Doc ...
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PM6670AS Figure 23. Over-voltage protection, VDDQ = 1.8 V Typical operating characteristics Figure 24. Under-voltage protection, VDDQ = 1.8 V Doc ID 14436 Rev 2 17/53 ...
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Block diagram 6 Block diagram Figure 25. Functional and block diagram VTTSNS VTTSNS VTTSNS LDOIN LDOIN LDOIN VTT VTT VTT VTTGND VTTGND VTTGND VTTREF VTTREF VTTREF SGND SGND SGND AVCC AVCC AVCC DDRSEL DDRSEL DDRSEL DSCG DSCG DSCG Table 7. ...
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PM6670AS 7 Device description The PM6670AS is designed to satisfy DDR2-3 power supply requirements combining a synchronous buck controller buffered reference and a high-current low-drop out (LDO) linear regulator capable of sourcing and sinking ...
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Device description 7.1 VDDQ section - constant on-time PWM controller The PM6670AS uses a pseudo-fixed frequency, constant on-time (COT) controller as the core of the switching section well known that the COT controller uses a relatively simple algorithm ...
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PM6670AS The duty-cycle of the buck converter is, in steady-state conditions, given by Equation 2 The switching frequency is thus calculated as Equation 3 where Equation 4a Equation 4b Referring to the typical application schematic (figures on cover page and ...
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Device description Figure 27. Switching frequency selection and VOSC pin The suggested voltage range for VOSC pin is 0.3V to 2V, for better switching frequency programmability. 7.1.1 Constant-on-time architecture Figure 28 shows the simplified block diagram of the constant-on-time controller. ...
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PM6670AS Figure 28. Switching section simplified block diagram 7.1.2 Output ripple compensation and loop stability The loop is closed connecting the center tap of the output divider (internally, when the fixed output voltage is chosen, or externally, using the MODE ...
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Device description Figure 29. Circuitry for output ripple compensation COMP PIN VOLTAGE Vr OUTPUT VOLTAGE The additional capacitor is used to reduce the voltage on the COMP pin when higher than 300 mVpp and is unnecessary for most of applications. ...
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PM6670AS Equation 7 where μs is the integrator trans conductance. In order to ensure stability it must be also verified that: Equation 8 If the ripple on the COMP pin is greater than the integrator 150 mV, ...
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Device description Figure 30. “Virtual-ESR” Network T NODE VOLTAGE ΔV 1 The ripple on the COMP pin is the sum of the output voltage ripple and the triangular ripple generated by the Virtual-ESR Network. In fact the Virtual-ESR Network behaves ...
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PM6670AS Equation 14 Moreover, the C INT Equation 15 where R is the sum of the ESR of the output capacitor and the equivalent ESR given by TOT the Virtual-ESR Network (R determines the minimum integrator capacitor value C Equation ...
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Device description 7.1.3 Pulse-skip and no-audible pulse-skip modes High efficiency at light load conditions is achieved by PM6670AS entering the pulse-skip mode (if enabled). When one of the two fixed output voltages is set, pulse-skip power saving is a default ...
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PM6670AS has taken place within 30 μs (typ.) since the last one (because the output voltage is still higher than the reference), a no-audible pulse-skip cycle begins. The low-side MOSFET is turned on and the output is driven to fall ...
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Device description When the MODE pin is connected the PM6670AS allows setting the VDDQ voltage to 1 1.5 V just forcing the DDRSEL multilevel pin ground respectively (see Figure 33 ...
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PM6670AS Figure 34. Current sensing scheme An internal 120 μA current source is connected to C input of the positive current limit comparator. When the voltage drop developed across the sensing parameter equals the voltage drop across the programming resistor ...
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Device description The soft-start allows a gradual increase of the internal current limit threshold during start-up reducing the input/output surge currents. At the beginning of start-up, the PM6670AS current limit is set to 25% of nominal value and the under ...
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PM6670AS 7.1.7 Power-Good signal The PG pin is an open drain output used to monitor output voltage through VSNS (in fixed output voltage mode) or MODE (in adjustable output voltage mode) pins and is enabled after the soft-start timer has ...
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Device description Figure 38. Fast discharge and soft discharge options VDDQ VDDQ VTT VTT 400mV 400mV 7.1.9 Gate drivers The integrated high-current gate drivers allow using different power MOSFETs. The high- side driver uses a bootstrap circuit which is supplied ...
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PM6670AS 7.1.11 Over voltage and under voltage protections When the switching output voltage is about 115% of its nominal value, a latched over- voltage protection (OVP) occurs. In this case the synchronous rectifier immediately turns on while the high-side MOSFET ...
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Device description 7.2 VTTREF buffered reference and VTT LDO section The PM6670AS provides the required DDR2/3 reference voltage on the VTTREF pin. The internal buffer tracks half the voltage on the VSNS pin and has a sink and source capability ...
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PM6670AS 7.3 S3 and S5 power management pins According to DDR2/3 memories supply requirements, the PM6670AS can manage all system states by connecting S3-S5 pins to their respective sleep-mode signals in the notebook's motherboard. Keeping S3 and ...
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Application information 8 Application information The purpose of this chapter is to show the design procedure of the switching section. The design starts from three main specifications: ● The input voltage range, provided by the battery or the AC adapter. ...
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PM6670AS where Equation 27a Equation 27b Referring to the typical application schematic (figure in cover page and expression is then: Equation 28 The switching frequency directly affects two parameters: ● Inductor size: greater frequencies mean smaller inductances. In most of ...
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Application information 8.1.1 Inductor selection Once the switching frequency has been defined, the inductance value depends on the desired inductor ripple current. Low inductance value means great ripple current that brings poor efficiency and great output noise. On the other ...
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PM6670AS The saturation current of the inductor should be greater than I saturation core inductors. Using soft-ferrite cores it is possible (but not advisable) to push the inductor working near its saturation current. In Table 13 some inductors are listed. ...
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Application information It must be taken into account that in some MLCC the capacitance decreases when the operating voltage is near the rated voltage. In applications are listed. Table 14. Evaluated MLCC for input filtering Manufacturer TAIYO YUDEN UMK325BJ106KM-T TAIYO ...
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PM6670AS If ceramic capacitors are used, the output voltage ripple due to inductor current ripple is negligible. Then the inductance could be smaller, reducing the size of the choke. In this case it is important that output capacitor can adsorb ...
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Application information where R is the drain-source on-resistance of the control MOSFET. DSon Switching losses are approximately given by: Equation 41 P switching where t and t ON OFF gate-driver current capability and the gate charge Q low R . ...
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PM6670AS Tested low-side MOSFETs are listed in Table 17. Evaluated low-side MOSFETs Manufacturer ST STS12NH3LL ST STS25NH3LL IR Dual N-MOS can be used in applications with lower output current. Table 18 shows some suitable dual MOSFETs for applications requiring about ...
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Application information 8.1.6 VDDQ current limit setting The valley current limit is set by R current. The valley of the inductor current I Equation 45 The output current limit depends on the current ripple as shown I Figure 39. Valley ...
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PM6670AS 8.1.7 All ceramic capacitors application Design of external feedback network depends on the output voltage ripple across the output capacitors' ESR. If the ripple is great enough (at least 20 mV), the compensation network simply consists ...
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Application information If the ripple on pin COMP is greater than the integrator output dynamic (150 mV), an additional capacitor C attenuation factor of the output ripple, select: Equation 50 In order to reduce noise on pin COMP, it's possible ...
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PM6670AS Select C as shown: Equation 52 Then calculate R in order to have enough ripple voltage on the integrator input: Equation 53 Where R is the new virtual output capacitor ESR. A good trade-off is to consider an VESR ...
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Package mechanical data 9 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available ...
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PM6670AS Figure 42. Package dimensions Doc ID 14436 Rev 2 Package mechanical data 51/53 ...
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Revision history 10 Revision history Table 21. Document revision history Date 14-Feb-2008 17-Feb-2010 52/53 Revision 1 Initial release. Updated: Coverpage, 2 Table 8 Doc ID 14436 Rev 2 Changes Table 2, Table 6, Section 7.1, Figure 28 PM6670AS and ...
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... PM6670AS Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...