STEVAL-ISA052V1 STMicroelectronics, STEVAL-ISA052V1 Datasheet
STEVAL-ISA052V1
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STEVAL-ISA052V1 Summary of contents
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Features ■ Switching section – 4 input voltage range – 0.6 V, ±1 % voltage reference – Selectable 1.5 V fixed output voltage – Adjustable 0 3.3 V output voltage – 1.237 V ±1 ...
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Contents Contents 1 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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PM6675S 7.2 LDO linear regulator section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Typical application circuit 1 Typical application circuit Figure 1. Application circuit V LDOIN 10 VSEL C IN4 23 LIN 4 LDO PG LPG 24 LOUT V LDO 2 LFB 1 LGND C OUT2 4/53 + IN3 ...
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PM6675S 2 Pin settings 2.1 Connections Figure 2. Pin connection (through top view) NOSKIP 24 1 LGND LFB PM6675 PM6675S LPG SGND AVCC 6 7 Pin settings 19 18 VCC LGATE PGND SPG LEN SWEN 13 12 5/53 ...
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Pin settings 2.2 Pin description Table 2. Pin functions N° Pin 1 LGND 2 LFB 3 NOSKIP 4 LPG 5 SGND 6 AVCC 7 VREF 8 VOSC 9 VSNS 10 VSEL 11 COMP 12 LILIM 13 SWEN 14 LEN 15 ...
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PM6675S Table 2. Pin functions (continued) N° Pin 19 CSNS 20 PHASE 21 HGATE 22 BOOT 23 LIN 24 LOUT 3 Electrical data 3.1 Maximum rating Table 3. Absolute maximum ratings Symbol V AVCC V VCC V PHASE 1. Free ...
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Electrical data 3.2 Thermal data Table 4. Thermal data Symbol R thJA T STG 3.3 Recommended operating conditions Table 5. Recommended operating conditions Symbol AVCC V VCC 8/53 Parameter Thermal resistance junction to ...
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PM6675S 4 Electrical characteristics Table 6. Electrical characteristics ° °C, VCC = AVCC = +5 V, LIN = 1.5 V and LOUT = 0 not otherwise A (1) specified Symbol Parameter Supply section ...
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Electrical characteristics Table 6. Electrical characteristics (continued ° °C, VCC = AVCC = +5 V, LIN = 1.5 V and LOUT = 0 not otherwise A (1) specified Symbol Parameter SMPS output SMPS ...
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PM6675S Table 6. Electrical characteristics (continued ° °C, VCC = AVCC = +5 V, LIN = 1.5 V and LOUT = 0 not otherwise A (1) specified Symbol Parameter Soft-end section Switching section ...
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Electrical characteristics Table 6. Electrical characteristics (continued ° °C, VCC = AVCC = +5 V, LIN = 1.5 V and LOUT = 0 not otherwise A (1) specified Symbol Parameter Power management section ...
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PM6675S 5 Typical operating characteristics Figure 3. VOUT efficiency vs load, 1 frequency = 400 kHz 100 0.01 0.10 1.00 Output Current [A] Figure 5. VOUT load regulation, ...
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Typical operating characteristics Figure 9. VOUT line regulation, 1 1.540 1.535 1.530 1.525 1.520 1.515 1.510 Input Voltage [V] Figure 11. VOUT line regulation, 1.5 V 1.5170 1.5165 1.5160 1.5155 1.5150 1.5145 1.5140 1.5135 ...
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PM6675S Figure 15. Switching frequency vs load - 1.5 V Figure 16. PWM waveforms 600 500 400 300 200 100 0 0.01 0.1 Output Current [A] Figure 17. No-audible pulse-skip waveforms Figure 19. Power-up sequence VCC above UVLO Pulse SKIP ...
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Typical operating characteristics Figure 21. Switching section output soft-end Figure 23. -1 1.8 A LOUT load transient, 0.9 V Figure 25 VOUT load transient, PWM 16/53 Figure 22. LDO section output soft-end Figure ...
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PM6675S Figure 27 VOUT load transient, Pulse-Skip Figure 29. Over-voltage protection, VOUT = 1.5 V Typical operating characteristics Figure 28 VOUT load transient, Pulse-Skip Figure 30. Under-voltage protection, VOUT = ...
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Block diagram 6 Block diagram Figure 31. Functional and block diagram 0.6V LFB LFB LFB LIN LIN LIN LOUT LOUT LOUT LGND LGND LPG LPG LPG SGND SGND SGND AVCC AVCC AVCC ...
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PM6675S 7 Device description The PM6675S combines a single high efficiency step-down controller and an independent Low Drop-Out (LDO) linear regulator in the same package. The switching controller section is a high-performance, pseudo-fixed frequency, Constant- On-Time (COT) based regulator specifically ...
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Device description 7.1 Switching section - constant on-time PWM controller The PM6675S employes 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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PM6675S 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 33. Switching frequency selection and VOSC pin The voltage seen at this pin must be greater than 0.8 V and lower than order to ensure the system linearity. 7.1.1 Constant-On-Time architecture Figure 34 shows ...
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PM6675S Figure 34. Switching section simplified block diagram Positive Current Limit comparator Positive Current Limit comparator Positive Current Limit comparator Positive Current Limit comparator CSNS CSNS CSNS CSNS + + - - 100uA 100uA 100uA 100uA + + VBG VBG ...
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Device description Figure 35. 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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PM6675S Equation 7 where µs is the integrator trans conductance. If the ripple on the COMP pin is greater than 150 mV, the auxiliary capacitor C added the desired attenuation factor of the output ...
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Device description Figure 36. "Virtual-ESR" network T NODE VOLTAGE ∆V 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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PM6675S Equation 13 Moreover, the C INT Equation 14 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 PM6675S by entering the Pulse-Skip Mode (if enabled). At light load conditions the zero-crossing comparator truncates the low- side switch On-Time as soon ...
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PM6675S No-audible pulse-skip mode Some audio-noise sensitive applications cannot accept the switching frequency to enter the audible range possible in Pulse-Skip mode with very light loads. For this reason, the PM6675S implements an additional feature to maintain ...
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Device description 7.1.4 Mode-of-operation selection Figure 39. VSEL and NOSKIP multifunction pin configurations The PM6675S has been designed to satisfy the widest range of applications. The device is provided with some multilevel pins which allow the user to choose the ...
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PM6675S Table 8. Mode-of-operation settings summary VSEL V > 4.3 V VSEL V < 3.7 V VSEL 7.1.5 Current sensing and current limit The PM6675S switching controller uses a valley current sensing algorithm to properly handle the current limit protection ...
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Device description It must be taken into account that the current limit circuit actually regulates the inductor valley current. This means that R maximum DC output current plus half of the inductor ripple current: Equation 21 The PM6675S provides also ...
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PM6675S Figure 42. Soft-start at heavy load (a) and short-circuit (b) conditions, Pulse-Skip enabled (a) 7.1.7 Switching section power good signal The SPG pin is an open drain output used to monitor output voltage through VSNS (in fixed output voltage ...
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Device description 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 by the +5 V rail. The BOOT and PHASE pins work respectively as supply ...
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PM6675S 7.1.12 Device thermal protection The internal control circuitry of the PM6675S self-monitors the junction temperature and turns all outputs off when the 150 °C limit has been overrun. This event causes the switching section to be immediately disabled and ...
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Device description A compensation capacitor Cc must be added to adjust the dynamic response of the loop. The value calculated according to the desired bandwidth of the LDO regulator and depends on the value of the feedback ...
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PM6675S Figure 46. Maximum LDO source able output current vs input voltage 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0.0 7.2.2 LDO section soft-start The LDO section soft-start is performed by clamping the current limit. ...
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Application information 8 Application information The purpose of this chapter is showing the design procedure of the switching section. The design starts from three main specifications: ● The input voltage range, provided by the battery or the external supply. The ...
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PM6675S where Equation 28a Equation 28b Referring to the typical application schematic (figure in cover page and expression is then: Equation 29 The switching frequency directly affects two parameters: ● Inductor size: greater frequencies mean smaller inductances. In notebook applications, ...
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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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PM6675S The saturation current of the inductor should be greater than I hard saturation core inductors. Using soft-ferrite cores is possible (but not advisable) to push the inductor working near its saturation current. In Table 11 some inductors suitable for ...
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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 12. Evaluated MLCC for input filtering Manufacturer TAIYO YUDEN UMK325BJ106KM-T TAIYO ...
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PM6675S If ceramic capacitors are used, the output voltage ripple due to inductor current ripple is negligible. Then the inductance should 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. DS(on) Switching losses are approximately given by: Equation 42 P switching where t and t ON OFF gate-driver current capability and the gate charge Q low R . ...
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PM6675S Table 15. Evaluated low-side MOSFETs Manufacturer ST STS12NH3LL ST STS25NH3LL IR Dual N-MOS can be used in applications with lower output current. Table 16 shows some suitable dual MOSFETs for applications requiring about 3 A. Table 16. Suitable dual ...
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Application information 8.1.6 VOUT current limit setting The valley current limit is set by R current. The valley of the inductor current I Equation 46 The output current limit depends on the current ripple as shown in Figure 48. Valley ...
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PM6675S 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 Equation 51 In order to reduce noise on the COMP pin, it's possible to introduce a resistor R together with C INT much greater (10 or more times) than the switching frequency: Equation 52 For most applications both ...
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PM6675S Then calculate R in order to have enough ripple voltage on the integrator input: Equation 54 Where R is the new virtual output capacitor ESR. A good trade-off is to consider an VESR equivalent ESR of 30-50 mΩ , ...
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Package mechanical data 9 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and ...
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PM6675S Figure 51. Package dimensions Package mechanical data 51/53 ...
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Revision history 10 Revision history Table 19. Document revision history Date 14-Feb-2008 52/53 Revision 1 Initial release PM6675S Changes ...
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... PM6675S 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. ...