Cool-Power® PI34xx-00 8 V to 18 Vin, 15 A Cool-Power ZVS Buck Regulator Product Description Features & Benefits The PI34xx-00 is a family of high efficiency DC-DC ZVS-Buck regulators integrating the controller, power switches and support components within a high density System-in-Package (SiP). • High Efficiency ZVS-Buck Topology The PI34xx-00 is designed to achieve optimum efficiency at low input voltage ranges (8 V to 18 V). The utilization of zero current soft turn-on provided by the high performance ZVS topology within the PI34xx-00 series increases point of load performance, providing best in class power efficiency with high throughput power. The PI34xx-00 requires only an external inductor and minimal capacitors to form a complete DC-DC switching mode buck regulator. • Input voltage range of 8 V to 18 V • Very-Fast transient response • Power-up into pre-biased load • High accuracy pre-trimmed output voltage • User adjustable soft-start & tracking • Parallel capable with single wire current sharing • Input Over/Undervoltage Lockout (OVLO/UVLO) • Output Overvoltage Protection (OVP) • Overtemperature Protection (OTP) • Fast and slow current limits • -40°C to 125°C operating range (TJ) Output Voltage Device IOUT Max Set Range PI3420-00-LGIZ 1.0 V 1.0 V to 1.4 V 15 A PI3421-00-LGIZ 1.8 V 1.4 V to 2.0 V 15 A PI3422-00-LGIZ 2.5 V 2.0 V to 3.1 V 15 A PI3423-00-LGIZ 3.3 V 2.3 V to 4.1 V 15 A PI3424-00-LGIZ 5.0 V 3.3 V to 6.5 V 15 A The ZVS architecture enables high frequency operation while minimizing switching losses and maximizing efficiency. The high switching frequency operation reduces the size of the external filtering components, improves power density, and enables very fast dynamic response to line and load transients. Applications • High efficiency systems • Computing, Communications, Industrial, Automotive Equipment Package Information • 10 mm x 14 mm x 2.6 mm LGA SiP The ZVS architecture enables operation up to 750 kHz while minimizing switching losses and the use of variable frequency extends high efficiency over a very wide dynamic range. The PI34xx-00 series has a minimum on time of 20ns which enables large step down conversion ratios. Cool-Power® Rev 1.2 vicorpower.com Page 1 of 30 09/2015 800 927.9474 PI34xx-00 Contents Contents Page Contents Application Description Page 23 Order Information 3 Thermal, Storage, and Handling Information 3 Output Voltage Trim 23 Absolute Maximum Ratings 4 Soft-Start Adjust and Tracking 24 Functional Block Diagram 4 Inductor Pairing 25 Pin Description 5 Thermal Derating 25 Package Pin-Out 5 Filter Considerations 25 PI3420-00-LGIZ Electrical Characteristics 6 Layout Guidelines 26 PI3421-00-LGIZ Electrical Characteristics 9 Recommended PCB Footprint and Stencil 27 PI3422-00-LGIZ Electrical Characteristics 12 Package Drawings 28 PI3423-00-LGIZ Electrical Characteristics 15 Revision History 29 PI3424-00-LGIZ Electrical Characteristics 18 Warranty 30 Thermal Derating Curves 21 Functional Description 22 ENABLE 22 Remote Sensing 22 Switching Frequency Synchronization 22 Soft-Start 22 Output Voltage Trim 22 Output Current Limit Protection 22 Input Undervoltage Lockout 22 Input Overvoltage Lockout 22 Output Ovevoltage Protection 23 Overtemperature Protection 23 Parallel Operation 23 Pulse Skip Mode (PSM) 23 Variable Frequency Operation 23 Cool-Power® Rev 1.2 vicorpower.com Page 2 of 30 09/2015 800 927.9474 PI34xx-00 Order Information Cool-Power Output Range IOUT Max Package Transport Media Set Range PI3420-00-LGIZ 1.0 V 1.0 to 1.4 V 15 A 10 mm x 14 mm 123-pin LGA TRAY PI3421-00-LGIZ 1.8 V 1.4 to 2.0 V 15 A 10 mm x 14 mm 123-pin LGA TRAY PI3422-00-LGIZ 2.5 V 2.0 to 3.1 V 15 A 10 mm x 14 mm 123-pin LGA TRAY PI3423-00-LGIZ 3.3 V 2.3 to 4.1 V 15 A 10 mm x 14 mm 123-pin LGA TRAY PI3424-00-LGIZ 5.0 V 3.3 to 6.5 V 15 A 10 mm x 14 mm 123-pin LGA TRAY Thermal, Storage, and Handling Information Name Rating Storage Temperature -65°C to 150°C Operating Junction Temperature -40°C to 125°C Soldering Temperature for 20 seconds 245°C MSL Rating 2 kV HBM Cool-Power® Rev 1.2 vicorpower.com Page 3 of 30 09/2015 800 927.9474 PI34xx-00 Absolute Maximum Ratings Name Rating VIN -0.7 V to 22 V VS1 -0.7 to 22 V, 25 V for 5 ns, -4 V for 5 ns VOUT See relevant product section SGND 100 mA PGD, SYNCO, SYNCI, EN, EAO, ADJ, TRK, ADR1, ADR2, SCL, SDA, REM -0.3 V to 5.5 V / 5 mA Notes: At 25°C ambient temperature. Stresses beyond these limits may cause permanent damage to the device. Operation at these conditions or conditions beyond those listed in the Electrical Characteristics is not guaranteed. All voltage nodes are referenced to PGND unless otherwise noted. Test conditions are per the specifications within the individual product Electrical Characteristics. Functional Block Diagram Vin VS1 VIN Q2 Q1 VOUT R4 REM Power Control R1 VCC ZVS Control SYNCO SYNCI PGD EN PGND Memory ADJ + 1V R2 Interface 0Ω ADR1 SDA ADR0 SCL SGND Simplified Block Diagram (I2C pins SCL, SDA, ADR0, and ADR1 are for factory use only. Not for use in application.) Cool-Power® Rev 1.2 vicorpower.com Page 4 of 30 09/2015 800 927.9474 EAO TRK Vout PI34xx-00 Pin Description Name Location Description SGND Block 1 Signal ground: Internal logic ground for EA, TRK, SYNCI, SYNCO and ADJ. SGND and PGND are star connected within the regulator package. PGND Block 2 Power ground: VIN and VOUT power returns. VIN Block 3 Input voltage: and sense for UVLO, OVLO and feed forward ramp. VOUT Block 5 Output voltage: and sense for power switches and feed-forward ramp. VS1 Block 4 Switching node: and ZVS sense for power switches. PGD A1 Parallel Good: Used for parallel timing management intended for lead regulator. EAO A2 Error amp output: External connection for additional compensation and current sharing. EN A3 Enable Input: Regulator enable control. Asserted high or left floating – regulator enabled; Asserted low, regulator output disabled. REM A5 Remote Sense: High side connection. Connect to output regulation point. ADJ B1 Adjust input: An external resistor may be connected between ADJ pin and SGND or VOUT to trim the output voltage up or down. TRK C1 Soft-start and track input: An external capacitor may be connected between TRK pin and SGND to decrease the rate of rise during soft-start. NC K3, A4 SYNCO K4 Synchronization output: Outputs a high signal for ½ of the minimum period for synchronization of other regulators. SYNCI K5 Synchronization input: Synchronize to the falling edge of external clock frequency. SYNCI is a high impedance digital input node and should always be connected to SGND when not in use. SDA D1 Data Line: Connect to SGND. Factory use only. Not for use in application. SCL E1 Clock Line: Connect to SGND. Factory use only. Not for use in application. ADR1 H1 Tri-state Address: No connect. Factory use only. Not for use in application. ADR0 G1 Tri-state Address: No connect. Factory use only. Not for use in application. No Connect: Leave pins floating. SYNCO 2 SYNCI 1 NC 123-Lead LGA (10mmx 14mm) Top View Package Pin-Out 3 4 5 6 7 PGND Block 2 8 9 10 11 12 13 14 SGND K Block 1 J VIN Block 3 ADR1 H Block 1: B2-4, C2-4, D2-3, E2-3, F1-3, G2-3, H2-3, J1-3, K1-2 Block 2: A8-10, B8-10, C8-10, D8-10, E4-10, F4-10, G4-10, H4-10, J4-10, K6-10 Block 3: G12-14, H12-14, J12-14, K12-14 Block 4: A12-14, B12-14, C12-14, D12-14, E12-14, Block 5: A6-7, B6-7, C6-7, D6-7 ADR0 G SGND F SCL E SDA D TRK C VS1 Block 4 ADJ B PGD A REM NC EN EAO VOUT Block 5 Cool-Power® Rev 1.2 vicorpower.com Page 5 of 30 09/2015 800 927.9474 PI34xx-00 PI3420-00-LGIZ (1.0 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 85 nH (Note 1) unless other conditions are noted. Parameter Input Voltage Input Current Input Current At Output Short (fault condition duty cycle) Symbol Conditions VIN_DC IIN_DC Input Specifications Minimum 1 mA load required VIN = 12 V, TC = 25°C, IOUT = 15 A IIN_Short Note [2] Input Quiescent Current IQ_VIN Input Voltage Slew Rate VIN_SR Output Specifications Note [2] Note [3] @25°C, 8 V <VIN <18 V @25°C, 0.5 A <IOUT <15 A IOUT = 7.5 A, COUT = 8 x100µF, 20 MHz BW, Note [4] UVLO Start Threshold UVLO Stop Hysteresis UVLO Stop Threshold OVLO Start Hysteresis UVLO/OVLO Fault Delay Time UVLO/OVLO Response Time Output Overvoltage Protection Over-Temperature Fault Threshold Over-Temperature Restart Hysteresis Protection VUVLO_START VUVLO_HYS VOVLO VOVLO_HYS tf_DLY Number of the switching frequency cycles tf +1% overdrive VOVP Above Set VOUT TOTP TOTP_HYS [3] [4] [5] [6] Max Unit 8 12 1.437 18 V A 10 mA 2.6 4 VOUT_DC VOUT_DC ∆VOUT(∆VIN) ∆VOUT(∆IOUT) VOUT_AC IOUT_DC IOUT_CL [2] Typ Disabled Enabled (no load) Note [2] Output Voltage Total Regulation Output Voltage Trim Range Line Regulation Load Regulation Output Voltage Ripple Continuous Output Current Range Current Limit [1] Min 0.987 1.0 1.0 mA 1 V/µs 1.013 1.4 V V % % mVp-p A A 0.10 0.20 27 0.001 15 18 7.20 4 19.71 1.56 130 7.60 5 20.75 1.83 128 500 20 135 30 8.00 6 21.78 2.1 140 V V V V Cycles ns % °C °C All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Cool-Power® Rev 1.2 vicorpower.com Page 6 of 30 09/2015 800 927.9474 PI34xx-00 PI3420-00-LGIZ (1.0 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 85 nH (Note 1) unless other conditions are noted. Parameter Symbol Conditions Min Typ Max Unit Timing Switching Frequency Fault Restart Delay fS tFR_DLY Synchronization Frequency Range SYNCI Threshold ∆fSYNCI VSYNCI Note [6] 600 30 Sync In (SYNCI) Relative to set switching frequency. Note [3] 50 kHz ms 110 2.5 % V Sync Out (SYNCO) SYNCO High SYNCO Low SYNCO Rise Time SYNCO Fall Time TRK Active Input Range TRK Max Output Voltage TRK Disable Threshold Charge Current (Soft–Start) Discharge Current (Fault) Soft-Start Time VSYNCO_HI VSYNCO_LO tSYNCO_RT tSYNCO_FT VTRK VTRK_MAX VTRK_OV ITRK ITRK_DIS tSS Source 1mA Sink 1mA 20pF load 20pF load 4.5 0.5 10 10 Soft Start And Tracking Internal reference tracking range. 0 20 -70 CTRK = 0uF 1.2 1.2 40 -50 6.8 2.2 V V ns ns 60 -30 V V mV µA mA ms 1.1 0.9 300 V V mV Enable High Threshold Low Threshold Threshold Hysteresis Enable Pull-Up Voltage (floating, unfaulted) Enable Pull-Down Voltage (floating, faulted) Source Current Sink Current [1] [2] [3] [4] [5] [6] VEN_HI VEN_LO VEN_HYS 0.9 0.7 100 1 0.8 200 VEN_PU 2 V VEN_PD 0 V IEN_SO IEN_SK -50 50 uA uA All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Cool-Power® Rev 1.2 vicorpower.com Page 7 of 30 09/2015 800 927.9474 PI34xx-00 PI3420-00-LGIZ (1.0 VOUT) Electrical Characteristics Efficiency at 25°C 100 95 Efficiency % 90 85 80 8 Vin 12 Vin 18 Vin 75 70 65 60 55 50 0 1 2 4 3 5 6 7 9 8 10 11 12 13 14 15 IOUT (A) Figure 1 — Regulator and inductor performance Figure 4 — 12 VIN to 1.0 VOUT, COUT = 8 X 100 µF Ceramic VOUT (Ch4) = 100 mV/Div, IOUT (Ch1) = 10 A/Div, 100 µS/Div Figure 2 — VOUT (Ch1) = 500 mV/Div, IIN (Ch4) = 1 A/Div, 800 µs/Div Figure 5 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Switching Frequency vs. Load Current Switching Frequency (kHz) 800 700 600 500 8 Vin 12 Vin 18 Vin 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 IOUT (A) Figure 6 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Figure 3 — Switching Frequency vs. Load Current Cool-Power® Rev 1.2 vicorpower.com Page 8 of 30 09/2015 800 927.9474 PI34xx-00 PI3421-00-LGIZ (1.8 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 125 nH (Note 1) unless other conditions are noted. Parameter Input Voltage Input Current Input Current At Output Short (fault condition duty cycle) Symbol Conditions VIN_DC IIN_DC Input Specifications Minimum 1 mA load required VIN = 12 V, TC = 25°C, IOUT = 15 A IIN_Short Note [2] Input Quiescent Current IQ_VIN Input Voltage Slew Rate VIN_SR Output Specifications Note [2] Note [3] @25°C, 8 V <VIN <18 V @25°C, 0.5 A <IOUT <15 A IOUT = 7.5 A, COUT = 8 x100µF, 20 MHz BW, Note [4] UVLO Start Threshold UVLO Stop Hysteresis UVLO Stop Threshold OVLO Start Hysteresis UVLO/OVLO Fault Delay Time UVLO/OVLO Response Time Output Overvoltage Protection Over-Temperature Fault Threshold Over-Temperature Restart Hysteresis Protection VUVLO_START VUVLO_HYS VOVLO VOVLO_HYS tf_DLY Number of the switching frequency cycles tf +1% overdrive VOVP Above Set VOUT TOTP TOTP_HYS [3] [4] [5] [6] Max Unit 8 12 2.46 18 V A 10 mA 2.6 4.3 VOUT_DC VOUT_DC ∆VOUT(∆VIN) ∆VOUT(∆IOUT) VOUT_AC IOUT_DC IOUT_CL [2] Typ Disabled Enabled (no load) Note [2] Output Voltage Total Regulation Output Voltage Trim Range Line Regulation Load Regulation Output Voltage Ripple Continuous Output Current Range Current Limit [1] Min 1.776 1.4 1.8 1.8 0.10 0.20 20.2 mA 1 V/µs 1.823 2.0 V V % % mVp-p A A 15 18 7.20 4 19.71 1.56 130 7.60 5 20.75 1.83 128 500 20 135 30 8.00 6 21.78 2.1 140 V V V V Cycles ns % °C °C All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Cool-Power® Rev 1.2 vicorpower.com Page 9 of 30 09/2015 800 927.9474 PI34xx-00 PI3421-00-LGIZ (1.8 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 125 nH (Note 1) unless other conditions are noted. Parameter Symbol Conditions Min Typ Max Unit Timing Switching Frequency Fault Restart Delay fS tFR_DLY Synchronization Frequency Range SYNCI Threshold ∆fSYNCI VSYNCI Note [6] 550 30 Sync In (SYNCI) Relative to set switching frequency. Note [3] 50 kHz ms 110 2.5 % V Sync Out (SYNCO) SYNCO High SYNCO Low SYNCO Rise Time SYNCO Fall Time TRK Active Input Range TRK Max Output Voltage TRK Disable Threshold Charge Current (Soft–Start) Discharge Current (Fault) Soft-Start Time VSYNCO_HI VSYNCO_LO tSYNCO_RT tSYNCO_FT VTRK VTRK_MAX VTRK_OV ITRK ITRK_DIS tSS Source 1mA Sink 1mA 20pF load 20pF load 4.5 0.5 10 10 Soft Start And Tracking Internal reference tracking range. 0 20 -70 CTRK = 0uF 1.2 1.2 40 -50 6.8 2.2 V V ns ns 60 -30 V V mV µA mA ms 1.1 0.9 300 V V mV Enable High Threshold Low Threshold Threshold Hysteresis Enable Pull-Up Voltage (floating, unfaulted) Enable Pull-Down Voltage (floating, faulted) Source Current Sink Current [1] [2] [3] [4] [5] [6] VEN_HI VEN_LO VEN_HYS 0.9 0.7 100 1 0.8 200 VEN_PU 2 V VEN_PD 0 V IEN_SO IEN_SK -50 50 uA uA All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Cool-Power® Rev 1.2 vicorpower.com Page 10 of 30 09/2015 800 927.9474 PI34xx-00 PI3421-00-LGIZ (1.8 VOUT) Electrical Characteristics Efficiency at 25°C 100 95 Efficiency % 90 85 80 8 Vin 12 Vin 18 Vin 75 70 65 60 55 50 0 1 2 4 3 5 6 7 9 8 10 11 12 13 14 15 IOUT (A) Figure 7 — Regulator and inductor performance Figure 10 — 12 VIN to 1.8 VOUT, COUT = 8 X 100 µF Ceramic VOUT (Ch2) = 100 mV/Div, IIN (Ch1) = 10 A/Div, 100 µS/Div Figure 8 — VOUT (Ch1) = 1V/Div, IIN (Ch4) = 2 A/Div, 800 µs/Div Figure 11 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Switching Frequency vs. Load Current Switching Frequency (kHz) 800 700 600 500 8 Vin 12 Vin 18 Vin 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 IOUT (A) Figure 12 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Figure 9 — Switching Frequency vs. Load Current Cool-Power® Rev 1.2 vicorpower.com Page 11 of 30 09/2015 800 927.9474 PI34xx-00 PI3422-00-LGIZ (2.5 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 125 nH (Note 1) unless other conditions are noted. Parameter Input Voltage Input Current Input Current At Output Short (fault condition duty cycle) Symbol Conditions VIN_DC IIN_DC Input Specifications Minimum 1 mA load required VIN = 12 V, TC = 25°C, IOUT = 15 A IIN_Short Note [2] Input Quiescent Current IQ_VIN Input Voltage Slew Rate VIN_SR Output Specifications Note [2] Note [3] @25°C, 8 V <VIN <18 V @25°C, 0.5 A <IOUT <15 A IOUT = 7.5 A, COUT = 8 x100µF, 20 MHz BW, Note [4] UVLO Start Threshold UVLO Stop Hysteresis UVLO Stop Threshold OVLO Start Hysteresis UVLO/OVLO Fault Delay Time UVLO/OVLO Response Time Output Overvoltage Protection Over-Temperature Fault Threshold Over-Temperature Restart Hysteresis Protection VUVLO_START VUVLO_HYS VOVLO VOVLO_HYS tf_DLY Number of the switching frequency cycles tf +1% overdrive VOVP Above Set VOUT TOTP TOTP_HYS [3] [4] [5] [6] [7] Max Unit 8 12 3.37 18 V A 10 mA 2.6 4.0 VOUT_DC VOUT_DC ∆VOUT(∆VIN) ∆VOUT(∆IOUT) VOUT_AC IOUT_DC IOUT_CL [2] Typ Disabled Enabled (no load) Note [2] Output Voltage Total Regulation Output Voltage Trim Range Line Regulation Load Regulation Output Voltage Ripple Continuous Output Current Range Current Limit [1] Min 2.465 2.0 2.5 2.5 0.10 0.20 14 mA 1 V/µs 2.535 3.1 V V % % mVp-p A A 15 18 7.20 4 19.71 1.56 130 7.60 5 20.75 1.83 128 500 20 135 30 8.00 6 21.78 2.1 140 V V V V Cycles ns % °C °C All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 12 of 30 09/2015 800 927.9474 PI34xx-00 PI3422-00-LGIZ (2.5 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 125 nH (Note 1) unless other conditions are noted. Parameter Symbol Conditions Min Typ Max Unit Timing Switching Frequency Fault Restart Delay fS tFR_DLY Synchronization Frequency Range SYNCI Threshold ∆fSYNCI VSYNCI Note [6] 650 30 Sync In (SYNCI) Relative to set switching frequency. Note [3] 50 kHz ms 110 2.5 % V Sync Out (SYNCO) SYNCO High SYNCO Low SYNCO Rise Time SYNCO Fall Time TRK Active Input Range TRK Max Output Voltage TRK Disable Threshold Charge Current (Soft–Start) Discharge Current (Fault) Soft-Start Time VSYNCO_HI VSYNCO_LO tSYNCO_RT tSYNCO_FT VTRK VTRK_MAX VTRK_OV ITRK ITRK_DIS tSS Source 1mA Sink 1mA 20pF load 20pF load 4.5 0.5 10 10 Soft Start And Tracking Internal reference tracking range. 0 20 -70 CTRK = 0uF 1.2 1.2 40 -50 6.8 2.2 V V ns ns 60 -30 V V mV µA mA ms 1.1 0.9 300 V V mV Enable High Threshold Low Threshold Threshold Hysteresis Enable Pull-Up Voltage (floating, unfaulted) Enable Pull-Down Voltage (floating, faulted) Source Current Sink Current [1] [2] [3] [4] [5] [6] [7] VEN_HI VEN_LO VEN_HYS 0.9 0.7 100 1 0.8 200 VEN_PU 2 V VEN_PD 0 V IEN_SO IEN_SK -50 50 uA uA All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 13 of 30 09/2015 800 927.9474 PI34xx-00 PI3422-00-LGIZ (2.5 VOUT) Electrical Characteristics Efficiency at 25°C 100 95 Efficiency % 90 85 80 8 Vin 12 Vin 18 Vin 75 70 65 60 55 50 0 1 2 4 3 5 6 7 9 8 10 11 12 13 14 15 IOUT (A) Figure 13 — Regulator and inductor performance Figure 16 — 12 VIN to 2.5 VOUT, COUT = 8 X 100 µF Ceramic VOUT (Ch2) = 100 mV/Div, IIN (Ch1) = 10 A/Div, 100 µS/Div Figure 14 — VOUT (Ch3) = 1V/Div, IIN (Ch4) = 2 A/Div, 800 µs/Div Figure 17 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Switching Frequency vs. Load Current Switching Frequency (kHz) 800 700 600 500 8 Vin 12 Vin 18 Vin 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 IOUT (A) Figure 18 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Figure 15 — Switching Frequency vs. Load Current Cool-Power® Rev 1.2 vicorpower.com Page 14 of 30 09/2015 800 927.9474 PI34xx-00 PI3423-00-LGIZ (3.3 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 150 nH (Note 1) unless other conditions are noted. Parameter Input Voltage Input Current Input Current At Output Short (fault condition duty cycle) Symbol Conditions VIN_DC IIN_DC Input Specifications Minimum 1 mA load required VIN = 12 V, TC = 25°C, IOUT = 15 A IIN_Short Note [2] Input Quiescent Current IQ_VIN Input Voltage Slew Rate VIN_SR Output Specifications Note [2] Note [3] @25°C, 8 V <VIN <18 V @25°C, 0.5 A <IOUT <15 A IOUT = 7.5 A, COUT = 8 x100µF, 20 MHz BW, Note [4] UVLO Start Threshold UVLO Stop Hysteresis UVLO Stop Threshold OVLO Start Hysteresis UVLO/OVLO Fault Delay Time UVLO/OVLO Response Time Output Overvoltage Protection Over-Temperature Fault Threshold Over-Temperature Restart Hysteresis Protection VUVLO_START VUVLO_HYS VOVLO VOVLO_HYS tf_DLY Number of the switching frequency cycles tf +1% overdrive VOVP Above Set VOUT TOTP TOTP_HYS [3] [4] [5] [6] [7] Max Unit 8 12 4.43 18 V A 10 mA 2.6 4 VOUT_DC VOUT_DC ∆VOUT(∆VIN) ∆VOUT(∆IOUT) VOUT_AC IOUT_DC IOUT_CL [2] Typ Disabled Enabled (no load) Note [2] Output Voltage Total Regulation Output Voltage Trim Range Line Regulation Load Regulation Output Voltage Ripple Continuous Output Current Range Current Limit [1] Min 3.25 2.3 3.30 3.3 0.10 0.10 17 mA 1 V/µs 3.36 4.1 V V % % mVp-p A A 15 18 7.20 4 19.71 1.56 130 7.60 5 20.75 1.83 128 500 20 135 30 8.00 6 21.78 2.1 140 V V V V Cycles ns % °C °C All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 15 of 30 09/2015 800 927.9474 PI34xx-00 PI3423-00-LGIZ (3.3 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 150 nH (Note 1) unless other conditions are noted. Parameter Symbol Conditions Min Typ Max Unit Timing Switching Frequency Fault Restart Delay fS tFR_DLY Synchronization Frequency Range SYNCI Threshold ∆fSYNCI VSYNCI Note [6] 700 30 Sync In (SYNCI) Relative to set switching frequency. Note [3] 50 kHz ms 110 2.5 % V Sync Out (SYNCO) SYNCO High SYNCO Low SYNCO Rise Time SYNCO Fall Time TRK Active Input Range TRK Max Output Voltage TRK Disable Threshold Charge Current (Soft–Start) Discharge Current (Fault) Soft-Start Time VSYNCO_HI VSYNCO_LO tSYNCO_RT tSYNCO_FT VTRK VTRK_MAX VTRK_OV ITRK ITRK_DIS tSS Source 1mA Sink 1mA 20pF load 20pF load 4.5 0.5 10 10 Soft Start And Tracking Internal reference tracking range. 0 20 -70 CTRK = 0uF 1.2 1.2 40 -50 6.8 2.2 V V ns ns 60 -30 V V mV µA mA ms 1.1 0.9 300 V V mV Enable High Threshold Low Threshold Threshold Hysteresis Enable Pull-Up Voltage (floating, unfaulted) Enable Pull-Down Voltage (floating, faulted) Source Current Sink Current [1] [2] [3] [4] [5] [6] [7] VEN_HI VEN_LO VEN_HYS 0.9 0.7 100 1 0.8 200 VEN_PU 2 V VEN_PD 0 V IEN_SO IEN_SK -50 50 uA uA All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 16 of 30 09/2015 800 927.9474 PI34xx-00 PI3423-00-LGIZ (3.3 VOUT) Electrical Characteristics Efficiency at 25°C 100 95 Efficiency % 90 85 80 8 Vin 12 Vin 18 Vin 75 70 65 60 55 50 0 1 2 4 3 5 6 7 9 8 10 11 12 13 14 15 IOUT (A) Figure 19 — Regulator and inductor performance Figure 22 — 12 VIN to 2.5 VOUT, COUT = 8 X 100 µF Ceramic VOUT (Ch2) = 100 mV/Div, IIN (Ch1) = 10 A/Div, 100 µS/Div Figure 20 — VOUT (Ch3) = 1 V/Div, IIN (Ch4) = 2 A/Div, 800 µs/Div Figure 23 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Switching Frequency vs. Load Current Switching Frequency (kHz) 800 700 600 500 8 Vin 12 Vin 18 Vin 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 IOUT (A) Figure 24 — COUT = 8 X 100 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Figure 21 — Switching Frequency vs. Load Current Cool-Power® Rev 1.2 vicorpower.com Page 17 of 30 09/2015 800 927.9474 PI34xx-00 PI3424-00-LGIZ (5.0 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 150 nH (Note 1) unless other conditions are noted. Parameter Input Voltage Input Current Input Current At Output Short (fault condition duty cycle) Symbol Conditions VIN_DC IIN_DC Input Specifications Minimum 1 mA load required VIN = 12 V, TC = 25°C, IOUT = 15 A IIN_Short Note [2] Input Quiescent Current IQ_VIN Input Voltage Slew Rate VIN_SR Output Specifications Note [2] Note [3] @25°C, 8 V <VIN <18 V @25°C, 0.5 A <IOUT <15 A IOUT = 7.5 A, COUT = 8 x100µF, 20 MHz BW, Note [4] UVLO Start Threshold UVLO Stop Hysteresis UVLO Stop Threshold OVLO Start Hysteresis UVLO/OVLO Fault Delay Time UVLO/OVLO Response Time Output Overvoltage Protection Over-Temperature Fault Threshold Over-Temperature Restart Hysteresis Protection VUVLO_START VUVLO_HYS VOVLO VOVLO_HYS tf_DLY Number of the switching frequency cycles tf +1% overdrive VOVP Above Set VOUT TOTP TOTP_HYS [3] [4] [5] [6] [7] Max Unit 8 12 6.57 18 V A 10 mA 2.6 4 VOUT_DC VOUT_DC ∆VOUT(∆VIN) ∆VOUT(∆IOUT) VOUT_AC IOUT_DC IOUT_CL [2] Typ Disabled Enabled (no load) Note [2] Output Voltage Total Regulation Output Voltage Trim Range Line Regulation Load Regulation Output Voltage Ripple Continuous Output Current Range Current Limit [1] Min 4.93 3.3 5 mA 1 V/µs 5.07 6.5 V V % % mVp-p A A 0.10 0.10 20.8 15 18 7.20 4 19.71 1.56 130 7.60 5 20.75 1.83 128 500 20 135 30 8.00 6 21.78 2.1 140 V V V V Cycles ns % °C °C All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 18 of 30 09/2015 800 927.9474 PI34xx-00 PI3424-00-LGIZ (5.0 VOUT) Electrical Characteristics Specifications apply for -40°C < TJ < 125°C, VIN =12 V, L1 = 150 nH (Note 1) unless other conditions are noted. Parameter Symbol Conditions Min Typ Max Unit Timing Switching Frequency Fault Restart Delay fS tFR_DLY Synchronization Frequency Range SYNCI Threshold ∆fSYNCI VSYNCI Note [6] 750 30 Sync In (SYNCI) Relative to set switching frequency. Note [3] 50 kHz ms 110 2.5 % V Sync Out (SYNCO) SYNCO High SYNCO Low SYNCO Rise Time SYNCO Fall Time TRK Active Input Range TRK Max Output Voltage TRK Disable Threshold Charge Current (Soft–Start) Discharge Current (Fault) Soft-Start Time VSYNCO_HI VSYNCO_LO tSYNCO_RT tSYNCO_FT VTRK VTRK_MAX VTRK_OV ITRK ITRK_DIS tSS Source 1mA Sink 1mA 20pF load 20pF load 4.5 0.5 10 10 Soft Start And Tracking Internal reference tracking range. 0 20 -70 CTRK = 0uF 1.2 1.2 40 -50 6.8 2.2 V V ns ns 60 -30 V V mV µA mA ms 1.1 0.9 300 V V mV Enable High Threshold Low Threshold Threshold Hysteresis Enable Pull-Up Voltage (floating, unfaulted) Enable Pull-Down Voltage (floating, faulted) Source Current Sink Current [1] [2] [3] [4] [5] [6] [7] VEN_HI VEN_LO VEN_HYS 0.9 0.7 100 1 0.8 200 VEN_PU 2 V VEN_PD 0 V IEN_SO IEN_SK -50 50 uA uA All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI34xx-00 evaluation board with 3 x 4” dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value. Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control. Output current capability may be limited and other performance may vary from noted electrical characteristics when switching frequency or VOUT is modified. Refer to Output Ripple plots. Refer to Load Current vs. Ambient Temperature curves. Refer to Switching Frequency vs. Load current curves. Minimum 5 V between Vin-Vout must be maintained or a minimum load of 1 mA required. Cool-Power® Rev 1.2 vicorpower.com Page 19 of 30 09/2015 800 927.9474 PI34xx-00 PI3424-00-LGIZ (5.0 VOUT) Electrical Characteristics Efficiency at 25°C 100 95 Efficiency % 90 85 80 8 Vin 12 Vin 18 Vin 75 70 65 60 55 50 0 1 2 4 3 5 6 7 9 8 10 11 12 13 14 15 IOUT (A) Figure 25 — Regulator and inductor performance Figure 28 — 12 VIN to 5.0 VOUT, COUT = 8 X 47 µF Ceramic VOUT (Ch2) = 200 mV/Div, IOUT (Ch1) = 10 A/Div, 100 µS/Div Figure 26 — VOUT (Ch1) = 2 V/Div, IIN (Ch4) = 5 A/Div, 800 µs/Div Figure 29 — COUT = 8 X 47 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Switching Frequency vs. Load Current Switching Frequency (kHz) 800 700 600 500 8 Vin 12 Vin 18 Vin 400 300 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 IOUT (A) Figure 30 — COUT = 8 X 47 µF Ceramic, VOUT = 20 mV/Div, 2.0 µs/Div Figure 27 — Switching Frequency vs. Load Current Cool-Power® Rev 1.2 vicorpower.com Page 20 of 30 09/2015 800 927.9474 PI34xx-00 Thermal Derating Curves PI3421 Load Current vs. Ambient Temperature, 0 LFM 16 16 14 14 12 10 8 Vin 12 Vin 18 Vin 8 6 4 Load Current (A) Load Current (A) PI3420 Load Current vs. Ambient Temperature, 0 LFM 12 10 8 Vin 12 Vin 18 Vin 8 6 4 2 2 0 0 25 35 45 55 65 75 85 95 105 25 115 35 45 Figure 31 — PI3420 - Load Current vs. Ambient Temperature, 0 LFM 75 85 95 105 115 PI3423 Load Current vs. Ambient Temperature, 0 LFM 16 16 14 14 12 10 8 Vin 12 Vin 18 Vin 8 6 4 2 Load Current (A) Load Current (A) 65 Figure 34 — PI3421 - Load Current vs. Ambient Temperature, 0 LFM PI3422 Load Current vs. Ambient Temperature, 0 LFM 12 10 8 Vin 12 Vin 18 Vin 8 6 4 2 0 0 25 35 45 55 65 75 85 95 105 115 25 35 45 Ambient Temperature (°C) 16 14 12 10 8 Vin 12 Vin 18 Vin 8 6 4 2 0 35 45 55 65 75 85 95 65 75 85 95 105 115 Figure 35 — PI3423 - Load Current vs. Ambient Temperature, 0 LFM PI3424 Load Current vs. Ambient Temperature, 0 LFM 25 55 Ambient Temperature (°C) Figure 32 — PI3422 - Load Current vs. Ambient Temperature, 0 LFM Load Current (A) 55 Ambient Temperature (°C) Ambient Temperature (°C) 105 115 Ambient Temperature (°C) Figure 33 — PI3424 - Load Current vs. Ambient Temperature, 0 LFM Cool-Power® Rev 1.2 vicorpower.com Page 21 of 30 09/2015 800 927.9474 PI34xx-00 Functional Description The PI34xx-00 is a family of highly integrated ZVS-Buck regulators. The PI34xx-00 has a set output voltage that is trimmable within a prescribed range shown in Table 1. Performance and maximum output current are characterized with a specific external power inductor (see Table 4). L1 VIN VIN CIN PGND PI34xx VOUT VS1 COUT VOUT Soft-Start The PI34xx-00 includes an internal soft-start capacitor to ramp the output voltage in 2ms from 0 V to full output voltage. Connecting an external capacitor from the TRK pin to SGND will increase the start-up ramp period. See, “Soft Start Adjustment and Track,” in the Applications Description section for more details. Output Voltage Trim The PI34xx-00 output voltage can be trimmed up from the preset output by connecting a resistor from ADJ pin to SGND and can be trimmed down by connecting a resistor from ADJ pin to VOUT. The Table 1 defines the voltage ranges for the PI34xx-00 family. REM TRK SYNCO ADJ EN EAO SGND SYNCI Device Figure 36 — ZVS-Buck with required components For basic operation, Figure 36 shows the connections and components required. No additional design or settings are required. ENABLE (EN) EN is the enable pin of the regulator. The EN Pin is referenced to SGND and permits the user to turn the regulator on or off. The EN polarity is a positive logic assertion. If the EN pin is left floating or asserted high, the regulator output is enabled. Pulling EN pin below 0.8 Vdc with respect to SGND will disable the regulator output. Remote Sensing An internal 100 Ω resistor is connected between REM pin and VOUT pin to provide regulation when the REM connection is broken. Referring to Figure 36, it is important to note that L1 and Cout are the output filter and the local sense point for the power supply output. As such, the REM pin should be connected at Cout as the default local sense connection unless remote sensing to compensate additional distribution losses in the system. The REM pin should not be left floating. Switching Frequency Synchronization The SYNCI input allows the user to synchronize the controller switching frequency by an external clock referenced to SGND. The external clock can synchronize the unit between 50% and 110% of the preset switching frequency (fS). The PI34xx-00 syncs to the falling edge of the applied clock providing 180° phase shift from SYNCO. This allows for the paralleling of two PI34xx-00 devices. When using the internal oscillator, the SYNCO pin provides a 5 V clock that can be used to sync other regulators. Therefore, one PI34xx00 can act as the lead regulator and have additional PI34xx-00s running in parallel and interleaved. Output Voltage Set Range PI3420-00-LGIZ 1.0 V 1.0 to 1.4 V PI3421-00-LGIZ 1.8 V 1.4 to 2.0 V PI3422-00-LGIZ 2.5 V 2.0 to 3.1 V PI3423-00-LGIZ 3.3 V 2.3 to 4.1 V PI3424-00-LGIZ 5.0 V 3.3 to 6.5 V Table 1 — PI34xx-00 family output voltage ranges Output Current Limit Protection PI34xx-00 has two methods implemented to protect from output short or over current condition. Slow Current Limit protection: prevents the output load from sourcing current higher than the regulator’s maximum rated current. If the output current exceeds the Current Limit (IOUT_CL) for 1024 us, a slow current limit fault is initiated and the regulator is shutdown which eliminates output current flow. After Fault Restart Delay (tFR_DLY), a soft-start cycle is initiated. This restart cycle will be repeated indefinitely until the excessive load is removed. Fast Current Limit protection: PI34xx-00 monitors the regulator inductor current pulse-by-pulse to prevent the output from supplying very high current due to sudden low impedance short (50 A Typical). If the regulator senses a high inductor current pulse, it will initiate a fault and stop switching until Fault Restart Delay ends and then initiate a soft-start cycle. Input Undervoltage Lockout If VIN falls below the input Undervoltage Lockout (UVLO) threshold, the regulator will enter a low power state and initiate a fault. The system will restart once the input voltage is reestablished and after the Fault Restart Delay. Input Overvoltage Lockout If VIN exceeds the input Overvoltage Lockout (OVLO) threshold (VOVLO), while the regulator is running, the PI34xx-00 will complete the current cycle and stop switching. The system will resume operation after the Fault Restart Delay. Cool-Power® Rev 1.2 vicorpower.com Page 22 of 30 09/2015 800 927.9474 PI34xx-00 Output Overvoltage Protection The PI34xx-00 family is equipped with output Overvoltage Protection (OVP) to prevent damage to input voltage sensitive devices. If the output voltage exceeds 20% of its set regulated value, the regulator will complete the current cycle, stop switching and issue an OVP fault. The system will resume operation once the output voltage falls below the OVP threshold and after Fault Restart Delay. Overtemperature Protection The internal package temperature is monitored to prevent internal components from reaching their thermal maximum. If the Over Temperature Protection Threshold (OTP) is exceeded (TOTP), the regulator will complete the current switching cycle, enter a low power mode, set a fault flag, and will soft-start when the internal temperature falls below OverTemperature Restart (TOTP_HYS). Parallel Operation Paralleling modules can be used to increase the output current capability of a single power rail and reduce output voltage ripple. L1 VIN VIN CIN R1 SYNCO(#2) VS1 VOUT VOUT COUT PGND PGD ZVS Buck (#1) REM EN(#2) EN EAO TRK(#2) TRK SGND L1 VIN VIN CIN SYNCO(#1) SYNCI(#1) EN(#1) VS1 VOUT PGND PGD Variable Frequency Operation Each PI34xx-00 is preprogrammed to a base operating frequency, with respect to the power stage inductor (see Table 4), to operate at peak efficiency across line and load variations. At low line and high load applications, the base frequency will decrease to accommodate these extreme operating ranges. By stretching the frequency, the ZVS operation is preserved throughout the total input line voltage range therefore maintaining optimum efficiency. Output Voltage Trim SYNCO EAO(#2) Pulse Skip Mode (PSM) PI34xx-00 features a PSM to achieve high efficiency at light loads. The regulators are setup to skip pulses if EAO falls below a PSM threshold. Depending on conditions and component values, this may result in single pulses or several consecutive pulses followed by skipped pulses. Skipping cycles significantly reduces gate drive power and improves light load efficiency. The regulator will leave PSM once the EAO rises above the Skip Mode threshold. Application Description SYNCI SYNCI(#2) initialize the open-loop startup synchronization. Once the regulators reach regulation, SYNCI is released and the system is now synchronized in a closed-loop configuration which allows the system to adjust, on the fly, when any of the individual regulators begin to enter variable frequency mode in the loop. COUT ZVS Buck (#2) REM The PI34xx-00 family of Buck Regulators provides five common output voltages: 1.0 V, 1.8 V, 2.5 V, 3.3 V and 5.0 V. A post-package trim step is implemented to offset any resistor divider network errors ensuring maximum output accuracy. With a single resistor connected from the ADJ pin to SGND or REM, each device’s output can be varied above or below the nominal set voltage (the PI3420-00 can only be adjusted above the set voltage of 1 V). SYNCI SYNCO Device EN EAO(#1) EAO TRK(#1) TRK SGND Figure 37 — PI34xx-00 parallel operation By connecting the EAO pins and SGND pins of each module together the units will share the current equally. When the TRK pins of each unit are connected together, the units will track each other during soft-start and all unit EN pins have to be released to allow the units to start (See Figure 37). Also, any fault event in any regulator will disable the other regulators. The two regulators will be out of phase with each other reducing output ripple (refer to Switching Frequency Synchronization). Output Voltage Set Range PI3420-00-LGIZ 1.0 V 1.0 to 1.4 V PI3421-00-LGIZ 1.8 V 1.4 to 2.0 V PI3422-00-LGIZ 2.5 V 2.0 to 3.1 V PI3423-00-LGIZ 3.3 V 2.3 to 4.1 V PI3424-00-LGIZ 5.0 V 3.3 to 6.5 V Table 2 — PI34xx-00 family output voltage ranges The remote pin (REM) should always be connected to the VOUT pin to prevent an output voltage offset. Figure 38 shows the internal feedback voltage divider network. To provide synchronization between regulators over the entire operational frequency range, the Parallel Good (PGD) pin must be connected to the lead regulator’s (#1) SYNCI pin and a 2.5 kΩ Resistor, R1, must be placed between SYNCO (#2) return and the lead regulator’s SYNCI (#1) pin, as shown in Figure 37. In this configuration, at system soft-start, the PGD pin pulls SYNCI low forcing the lead regulator to Cool-Power® Rev 1.2 vicorpower.com Page 23 of 30 09/2015 800 927.9474 PI34xx-00 Resistor R_high should be connected as shown in Figure 38 to achieve the desired 4.0 V regulator output. No external R_low resistor is need in this design example since the trim is above the regulator set voltage. VOUT The PI3420 output voltage can only be trimmed higher than the factory 1 V setting. The following Equation (3) can be used calculate Rhigh values for the PI3420 regulators. R4 REM Rlow R1 ADJ + Rhigh R2 1.0 Vdc SGND Figure 38 — Internal resistor divider network R1, R2, and R4 are all internal 1.0 % resistors and R_low and R_high are external resistors for which the designer can add to modify VOUT to a desired output. The internal resistor values for each regulator are listed next in Table 3. Device R1 R2 R4 PI3420-00-LGIZ 1k ∞ 100 PI3421-00-LGIZ 0.806 k 1.0 k 100 PI3422-00-LGIZ 1.5 k 1.0 k 100 PI3423-00-LGIZ 2.61 k 1.13 k 100 PI3424-00-LGIZ 4.53 k 1.13 k 100 Table 3 — PI34xx-00 Internal divider values By choosing an output voltage value within the ranges stated in Table 2, VOUT can simply be adjusted up or down by selecting the proper R_high or R_low value, respectively. The following equations can be used to calculate R_high and R_low values: Soft-Start Adjust and Tracking The TRK pin offers a means to increase the regulator’s softstart time or to track with additional regulators. . The softstart slope is controlled by an internal capacitor and a fixed charge current to provide a Soft-Start Time tSS for all for all PI34xx-00 regulators. By adding an additional external capacitor to the TRK pin, the soft-start time can be increased further. The following equation can be used to calculate the proper capacitor for a desired soft-start times: CTRK = (tTRK x ITRK) – 100 x 10 -9, where, tTRK is the soft-start time and ITRK is a 50 μA internal charge current (see Electrical Characteristics for limits). There is typically either a proportional or direct tracking method implemented within a tracking design. For proportional tracking between several regulators at startup, simply connect all devices TRK pins together. This type of tracking will force all connected regulators to startup and reach regulation at the same time (see Figure 39 (a)). For Direct Tracking, choose the regulator with the highest output voltage as the master and connect the master TRK pin to the TRK pin of the other regulators through a divider (Figure 40) with the same ratio as the slave’s feedback divider (see Table 3 for values). VOUT 1 VOUT 2 (a) Master VOUT VOUT 2 If, for example, a 4.0 V output is needed, the user should choose the regulator with a trim range covering 4.0 V from Table 2. For this example, the PI3423 is selected (3.3 V set voltage). First step would be to use Equation (1) to calculate R_HIGH since the required output voltage is higher than the regulator set voltage. The resistor-divider network values for the PI3423 can be found in Table 3 and are R1 = 2.61k Ω and R2 = 1.13 kΩ. Inserting these values in to Equation (1), R_HIGH is calculated as follows: (b) t Figure 39 — PI34xx-00 tracking methods All connected regulators’ soft-start slopes will track with this method. Direct tracking timing is demonstrated in Figure 39 (b). Cool-Power® Rev 1.2 vicorpower.com Page 24 of 30 09/2015 800 927.9474 PI34xx-00 Thermal Derating Thermal de-rating curves are provided that are based on component temperature changes versus load current, input voltage and air flow. It is recommended to use these curves as a guideline for proper thermal de-rating. These curves represent the entire system and are inclusive to both the Picor regulator and the external inductor. Maximum thermal operation is limited by either the MOSFETs or inductor depending upon line and load conditions. Thermal measurements were made using a standard PI34xx00 Evaluation board which is 3 x 4 inches in area and uses 4layer, 2oz copper. Thermal measurements were made on the three main power devices, the two internal MOSFETs and the external inductor. Master VOUT R1 PI34xx TRK Slave R2 SGND Filter Considerations The PI34xx-00 requires input bulk storage capacitance as well as low impedance ceramic X5R input capacitors to ensure proper start up and high frequency decoupling for the power stage. The PI34xx-00 will draw nearly all of the high frequency current from the low impedance ceramic capacitors when the main high side MOSFET is conducting. During the time the high side MOSFET is off, they are replenished from the bulk capacitor. If the input impedance is high at the switching frequency of the regulator, the bulk capacitor must supply all of the average current into the regulator, including replenishing the ceramic capacitors. This value has been chosen to be 100μF so that the PI34xx-00 can start up into a full resistive load and supply the output capacitive load with the default minimum soft start capacitor when the input source impedance is 50 Ohms at 1MHz. The ESR for this capacitor should be approximately 20mΩ. The RMS ripple current in this capacitor is small, so it should not be a concern if the input recommended ceramic capacitors are used. Table 5 shows the recommended input and output capacitors to be used for the various models as well as expected transient response, RMS ripple currents per capacitor, and input and output ripple voltages. Table 6 includes the recommended input and output ceramic capacitors. Figure 40 — Voltage divider connections for direct tracking All tracking regulators should have their Enable (EN) pins connected together to work properly. Inductor Pairing The PI34xx-00 utilizes an external inductor from the Eaton Inductor line at Cooper Industries. This inductor has been optimized for maximum efficiency performance. Table 4 details the specific inductor value and part number utilized for each PI34xx-00 device. Datasheets are available at www.cooperindustries.com. Inductor Inductor [nH} Part Number PI3420-00 85 FPV1006-85-R Eaton PI3421-00 125 FPV1006-125-R Eaton PI3422-00 125 FPV1006-125-R Eaton PI3423-00 150 FPV1006-150-R Eaton PI3424-00 150 FPV1006-150-R Eaton Device Manufacturer Table 4 — PI34xx-00 Inductor pairing Device VIN (V) PI3420 12 ILOAD (A) 15 7.5 15 PI3421 12 7.5 15 PI3422 12 7.5 15 PI3423 12 7.5 15 PI3424 12 7.5 CINPUT Bulk Elec. CINPUT Ceramic X5R COUTPUT Ceramic X5R CINPUT Ripple Current (IRMS) COUTPUT Ripple Current (IRMS) 100 µF 50 V 6 x 22 µF 8 X 100 µF 2 X 1 µF 1 X 0.1 µF 0.85 1.24 100 µF 50 V 6 x 22 µF 8 X 100 µF 2 X 1 µF 1 X 0.1 µF 1.0 100 µF 50 V 6 x 22 µF 8 X 100 µF 2 X 1 µF 1 X 0.1 µF 1.12 100 µF 50 V 6 x 22 µF 8 X 100 µF 2 X 1 µF 1 X 0.1 µF 1.20 100 µF 50 V 6 x 22 µF 8 X 47 µF 2 X 1 µF 1 X 0.1 µF 1.29 Input Ripple (mVpp) Output Ripple (mVpp) 98 36 43 27 139 32 45 20.4 145 28 74 14 179 26 97 17 209 34 98 24.8 1.18 1.16 1.15 1.13 Table 5 — Recommended input and output capacitance Cool-Power® Rev 1.2 vicorpower.com Page 25 of 30 09/2015 800 927.9474 Output Ripple (mVpk) Recovery Time (µs) Load Step (A) (Slew/µs) -/+41 42 7.5 (5 A/µs) -/+50 50 7.5 (5 A/µs) -/+46 60 7.5 (5 A/µs) -/+73 70 7.5 (5 A/µs) -/+98 60 7.5 (5 A/µs) PI34xx-00 Murata Part Number Description GRM188R71C105KA12D 1 µF 16 V 0603 X7R GRM319R71H104KA01D 0.1 µF 50 V 1206 X7R GRM31CR60J107ME39L 100 µF 6.3 V 1206 X5R GRM31CR61A476ME15L 47 µF 10 V 1206 X5R GRM31CR61E226KE15L 22 µF 25 V 1206 X5R When Q1 is on and Q2 is off, the majority of CIN’s current is used to satisfy the output load and to recharge the COUT capacitors. When Q1 is off and Q2 is on, the load current is supplied by the inductor and the COUT capacitor as shown in Figure 43. During this period CIN is also being recharged by the VIN. Minimizing CIN loop inductance is important to reduce peak voltage excursions when Q1 turns off. Also, the difference in area between the CIN loop and COUT loop is vital to minimize switching and GND noise. Table 6 — Capacitor manufacturer part numbers Layout Guidelines To achieve maximum efficiency and low noise performance from a PI34xx-00 design, layout considerations are necessary. Reducing trace resistance and minimizing high current loop returns along with proper component placement will contribute to optimal performance. I CNV NV A typical buck regulator circuit is shown in Figure 41. The potential areas of high parasitic inductance and resistance are the circuit return paths, shown as LR below. COUT Figure 43 — Current flow: Q2 closed VIN The recommended component placement, shown in Figure 44, illustrates the tight path between CIN and COUT (and VIN and VOUT) for the high AC return current. This optimized layout is used on the PI34xx-00 evaluation board. Figure 41 — Typical Buck Regulator The path between the COUT and CIN capacitors is of particular importance since the AC currents are flowing through both of them when Q1 is turned on. Figure 42, schematically, shows the reduced trace length between input and output capacitors. The shorter path lessens the effects that copper trace parasitics can have on the PI34xx-00 performance. VOUT COUT GND CIN VSW VIN GND I NV CNV Figure 44 — Recommended component placement and metal routing Figure 45 details the recommended receiving footprint for PI34xx-00 10 mm x 14 mm package. All pads should have a final copper size of 0.55 mm x 0.5 5mm, whether they are solder-mask defined or copper defined, on a 1 mm x 1 mm grid. All stencil openings are 0.55 mm when using 6mil stencil. COUT Figure 42 — Current flow: Q1 closed Cool-Power® Rev 1.2 vicorpower.com Page 26 of 30 09/2015 800 927.9474 PI34xx-00 Recommended PCB Footprint and Stencil Figure 45 — Recommended Receiving PCB footprint Cool-Power® Rev 1.2 vicorpower.com Page 27 of 30 09/2015 800 927.9474 PI34xx-00 Package Drawings Cool-Power® Rev 1.2 vicorpower.com Page 28 of 30 09/2015 800 927.9474 PI34xx-00 Revision History Revision Date 1.0 02/13 1.1 1.2 Description Page Number(s) Last release in old format n/a 08/03/15 Reformatted in new template n/a 09/03/15 Inductor pairing table updates 6, 7 & 25 Cool-Power® Rev 1.2 vicorpower.com Page 29 of 30 09/2015 800 927.9474 PI34xx-00 Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC modules and accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom power systems. Information furnished by Vicor is believed to be accurate and reliable. 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