SP6127_07 SIPEX | Alldatasheet

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Rev 6/27/07 SP6127 Evaluation Manual Copyright 2007 Sipex Corporation SP6127EB SCHEMATIC High=Of f L1, IHLP-2525CZ 3.3uH, 30mOhm, 6A 22uF Ds MBRA340T3G 200k, 1% RZ 2K R2 100k, 1% Si2343DS CZ 33pF 0.1uF 4.7uF Rs=1k D1 1N4148 SHDN 12V VIN VOUT GND GND VFB Vin GND VDR 1.8V 0-2.0A Gate LX SP6127 /square4 Easy Evaluation for the SP6127EK1 12V Input, 0 to 2A Output Non-Synchronous Buck Converter /square4 Precision 0.60V ±1% High -Accuracy Reference. /square4 Small form factor /square4 Feature Rich: Single supply operation, Over- current protection with auto-restart, on/off function, Preset internal soft start, Type-II internal compensation SP61 27, 2A Evaluation Board Manual

USING THE EVALUATION BOARD 1) Powering Up the SP6127EB Circuit Connect the SP6127 Evaluation Board to an external +12V power supply. Connect with short leads directly to the “VIN” and “GND” posts. Connect a Load between the “VOUT” and “GND” posts, again using short leads to minimiz e inductance and voltage drop. 2) Measuring Output Load Characteristics It’s best to GND reference scope and digital meters using the Star GND post near the output of the board. VOUT ripple can best be seen touching probe tip to the pad for COUT and scope GND collar touching Star GND post – avoid a GND lead on the scope which will increase noise pickup. 3) Using the Evaluation Board with Different Output Voltages While the SP6127 Evaluation Board has been tested and delivered with the output set to 1.80V, by simply changing one resistor, R2, the SP6127 can be set to other output voltages. The relationship in the following formula is based on a voltage divider from the output to the feedback pin FB, which is set to an internal reference voltage of 0.60V. Standard 1% metal film resistors of surface mount size 0603 are recommended.  − Vref Vout RR Where R1 = 200k Ω . For Vout = 0.60V setting, simply remove R2 from the board. Note that since the SP6127 Evaluation Board design was optimized for 12V down conversion to 1.80V, changes of output voltage and/or input voltage will alter performance from the data given in the Power Supply Data section. Using the SHDN (ON/OFF function) Feedback pin serves a dual role of ON/OFF control. The MOSFET driver is disabled when a voltage greater than 1V is applied at FB pin. Maximum voltage rating of this pin is 5.5V. The controlling signal should be applied through a small signal diode as shown on page 1. Note that under no-load condition an optional 10kOhm bleeding resistor across the output helps keep the output capacitor discharged. POWER SUPPLY DATA The SP6127EB is designed with an accurate 2% reference over line, load and temperature. Figure 1 data shows a typical SP6127 Evaluation Board efficiency plot, with efficiencies to 75% and output currents to 2A. SP6127 Load Regulation in Figure 2 shows very little change in output voltage from no load to 2A load. Figures 3 and 4 show the transient response of the SP6127 and overcurrent shutdown. Figures 5 and 6 show a controlled start-up with no load and 2A load when power is applied where the input current rises smoothly as the soft-start ramp increases. Figures 7 and 8 show the output ripple under no load and 2A load.

Typical Performance Characteristics Figure 7- Output ripple at 0A is 32mV, Figure 8- Output ripple at 2A is 15mV, ch1: Vin, ch2: Vout, ch3: Iout ch1: Vin, ch2: Vout, ch3: Iout

The SP6127 includes Type-II internal compensation components for loop compensation. External compensation components are not required for systems with tantalum or aluminum electrolytic output capacitors with sufficiently high ESR. Use the condition below as a guideline to determine whether or not the internal compensation is sufficient for your design. Type-II internal compensation is sufficient if the following condition is met: where: OUT ESR ESRZERO CRf ... 2 π= ……….. (2) OUT DBPOLE CL f .. 2 π ………… (3) Creating a Type-III compensation Network The above condition requires the ESR zero to be at a lower frequency than the double- pole from the LC filter. If this condition is not met, Type-III compensation should be used and can be accomplished by placing a series RC combination in parallel with R1 as shown below. The value of CZ can be calculated as follows and RZ selected from table 1. 125 .1 R CLCZ × Table1- Selection of RZ f ESRZERO/f DBPOLE RZ 1X 50K 2X 40K 3X 30K 5X 10K >= 10X 2K

200k, 1% SP6127 VFB RZ2 200k CZ2 130pF CP1 2pF Error Amplif ier Vref =0.6V Vout RZ CZ Figure 9- RZ and CZ in conjunction with internal compensation components form a Type-III compensation Loop Compensation for the SP6127EB L = 3.3uH, C = 22uF/5mOhm ceramic capacitor From equation (2) f ESRZERO = 1.45MHz. From equation (3) f DBPOLE = 18.7 kHz. Since the condition specified in (1) is not met, Type-III compensation has to be used by adding external components RZ and CZ. Using equation (4) CZ is calculated 34pF (use 33pF). Following the guideline given in table 1, a 2kOhm RZ was used.

Line Ref. Qty. Manuf. Manuf. Layout Component Vendor No. Des. Part Number Size Phone Number 1 PCB 1 Sipex 146-6641-00 1.175"x1.934" SP6127EB 408-934-7 500

2 U1 1 Sipex SP6127EK1 TSOT-6 Non-synchronous Buck Contro ller 408-934-7500

3 Q1 1 Vishay Semi Si2343DS SOT-23 PFET, 30V, 86mOhm 402-563-6866

4 DS 1 On Semi MBRA340T3 SMA Schotkky, 40V, 3A 602-244-6600

5 L1 1 Vishay IHLP2525CZ 6.86x6.47mm 3.3uH Coil 6A 30mOh m 914-347-2474

6 D1 1 MCC 1N4148WX SOD323 Fast Switching Diode 500mW 818- 701-4933

7 C1 1 MURATA GRM21BR61E475K 0805 4.7 uF Ceramic X5R 25V 7 70-436-1300 8 C6 1 MURATA GRM21BR60J226M 0805 22uF Ceramic X5R 6.3V 7 70-436-1300 9 C7 1 MURATA GRM18ER61E104K 0603 0.1uF Ceramic X5R 770-43 6-1300

10 CZ 1 MURATA GRM1885C1H330JA 0603 33pF Ceramic C0G 50V 7 70-436-1300

11 R1 1 VISHAY/DALE CRCW0603200K 0603 200k 402-563-6866

12 R2 1 VISHAY/DALE CRCW060344K2 0603 100k 402-563-6866

13 RZ 1 VISHAY/DALE CRCW06037K15 0603 2.00k 402-563-6866 VIN, VOUT, GND, GND, SHDN 5 Vector Electronic K24C/M .042 Dia Test Point Post 800- 344-4539 Table 2- SP6127EB List of Materials D C R Isat M anufacturer m O hm s (A ) LxW (m m ) H t.(m m ) W ebsite ES R R ipple C urrent Voltage C apacitor M anufacturer ohm s (m ax) (A ) @ 20C D elta LxW (m m ) H t.(m m ) (V ) Type W ebsite M O SFE TS - SU R FA C E M O U N T R D S(on) ID C urrent Voltage Foot P rint M anufacturer ohm s (m ax) (A ) nC (Typ) nC (M ax) (V ) W ebsite IN D U C TO R S - S U R FA C E M O U N T C A P A C ITO R S - SU R FA C E M O U N T C apacitance( uF) Inductance (uH ) S ize Inductor Type S ize C apacitor S pecification M anufacturer/P art N o. M anufacturer/P art N o. Inductor S pecification M O S FET M anufacturer/P art N o. M O S FET Specification Q g Table 3- SP6127EB Suggested Components and Vendor Lists

ORDERING INFORMATION

Model Temperature Range Package Type