TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 D D D D D D D D D D D D Floating Bootstrap or Ground-Reference High-Side Driver Active Deadtime Control 50-ns Max Rise/Fall Times With 3.3-nF Load 2-A Min Peak Output Current 4.5-V to 15-V Supply Voltage Range TTL-Compatible Inputs Internal Schottky Bootstrap Diode SYNC Control for Synchronous or Nonsynchronous Operation CROWBAR for OVP, Protects Against Faulted High-Side Power FETs Low Supply Current . . . 3 mA Typ Ideal for High-Current Single- or Multiphase Applications –40°C to 125°C Junction-Temperature Operating Range D OR PWP PACKAGE (TOP VIEW) 1 2 3 4 5 6 7 ENABLE IN CROWBAR NC SYNC DT PGND 14 13 12 11 10 9 8 BOOT NC HIGHDR BOOTLO LOWDR NC VCC NC – No internal connection description The TPS2834 and TPS2835 are MOSFET drivers for synchronous-buck power stages. These devices are ideal for designing a high-performance power supply using a switching controller that does not include suitable on-chip MOSFET drivers. The drivers are designed to deliver minimum 2-A peak currents into large capacitive loads. The high-side driver can be configured as ground-reference or as floating-bootstrap. An adaptive dead-time control circuit eliminates shoot-through currents through the main power FETs during switching transitions, and provides high efficiency for the buck regulator. The TPS2834 and TPS2835 have additional control functions: ENABLE, SYNC, and CROWBAR. Both high-side and low-side drivers are off when ENABLE is low. The low-side driver is configured as a nonsynchronous-buck driver when SYNC is low. The CROWBAR function turns on the low-side power FET, overriding the IN signal, for overvoltage protection against faulted high-side power FETs. The TPS2834 has a noninverting input, while the TPS2835 has an inverting input. These drivers are available in 14-terminal SOIC and TSSOP packages and operate over a junction temperature range of –40°C to 125°C. AVAILABLE OPTIONS PACKAGED DEVICES TJ SOIC (D) –40°C to 125°C TPS2834D TPS2835D TSSOP (PWP) TPS2834PWP TPS2835PWP The D and PWP packages are available taped and reeled. Add R suffix to device type (e.g., TPS2834DR) Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 1999, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 functional block diagram 8 14 200 kΩ (TPS2834 Only) 200 kΩ 2 12 11 VCC BOOT HIGHDR BOOTLO IN VCC (TPS2835 Only) 10 200 kΩ 7 6 LOWDR PGND DT ENABLE 1 5 SYNC CROWBAR 3 Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION BOOT 14 I Bootstrap terminal. A ceramic capacitor is connected between BOOT and BOOTLO to develop the floating bootstrap voltage for the high-side MOSFET. The capacitor value is typically between 0.1 µF and 1 µF. BOOTLO 11 O This terminal connects to the junction of the high-side and low-side MOSFETs. CROWBAR 3 I CROWBAR can to be driven by an external OVP circuit to protect against a short across the high-side MOSFET. If CROWBAR is driven low, the low-side driver will be turned on and the high-side driver will be turned off, independent of the status of all other control terminals. DT 6 I Deadtime control terminal. Connect DT to the junction of the high-side and low-side MOSFETs. ENABLE 1 I If ENABLE is low, both drivers are off. HIGHDR 12 O Output drive for the high-side power MOSFET IN 2 I Input signal to the MOSFET drivers (noninverting input for the TPS2834; inverting input for the TPS2835). 10 O Output drive for the low-side power MOSFET LOWDR NC 4, 9, 13 PGND 7 SYNC 5 I Synchronous rectifier enable terminal. If SYNC is low, the low-side driver is always off; If SYNC is high, the low-side driver provides gate drive to the low-side MOSFET. VCC 8 I Input supply. Recommended that a 1-µF capacitor be connected from VCC to PGND. 2 Power ground. Connect to the FET power ground POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 detailed description low-side driver The low-side driver is designed to drive low rDS(on) N-channel MOSFETs. The current rating of the driver is 2 A, source and sink. high-side driver The high-side driver is designed to drive low rDS(on) N-channel MOSFETs. The current rating of the driver is 2 A, source and sink. The high-side driver can be configured as a GND-reference driver or as a floating bootstrap driver. The internal bootstrap diode is a Schottky, for improved drive efficiency. The maximum voltage that can be applied from BOOT to ground is 30 V. dead-time (DT) control Dead-time control prevents shoot-through current from flowing through the main power FETs during switching transitions by controlling the turnon times of the MOSFET drivers. The high-side driver is not allowed to turn on until the gate drive voltage to the low-side FET is low, and the low-side driver is not allowed to turn on until the voltage at the junction of the power FETs (Vdrn) is low; the TTL-compatible DT terminal connects to the junction of the power FETs. ENABLE The ENABLE terminal enables the drivers. When enable is low, the output drivers are low. ENABLE is a TTL-compatible digital terminal. IN The IN terminal is a TTL-compatible digital terminal that is the input control signal for the drivers. The TPS2834 has a noninverting input; the TPS2835 has an inverting input. SYNC The SYNC terminal controls whether the drivers operate in synchronous or nonsynchronous mode. In synchronous mode, the low-side FET is operated as a synchronous rectifier. In nonsynchronous mode, the low-side FET is always off. SYNC is a TTL-compatible digital terminal. CROWBAR The CROWBAR terminal overrides the normal operation of the driver. When CROWBAR is low, the low-side FET turns on to act as a clamp, protecting the output voltage of the dc/dc converter against overvoltages due to a short across the high-side FET. VIN should be fused to protect the low-side FET. CROWBAR is a TTL-compatible digital terminal. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Supply voltage range, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 16 V Input voltage range: BOOT to PGND (high-side driver ON) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 30 V BOOTLO to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 16 V BOOT to BOOTLO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 16 V ENABLE, SYNC, and CROWBAR (see Note 2) . . . . . . . . . . . . . . . . . . . . . –0.3 V to 16 V IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 16 V DT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 30 V Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table Operating virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to 125°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C Lead temperature soldering 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . 260°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTES: 1. Unless otherwise specified, all voltages are with respect to PGND. DISSIPATION RATING TABLE PACKAGE TA ≤ 25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA = 70°C POWER RATING TA = 85°C POWER RATING D 760 mW 7.6 mW/°C 420 mW 305 mW PWP 2400 mW 25 mW/°C 1275 mW 900 mW recommended operating conditions MIN NOM MAX UNIT Supply voltage, VCC 4.5 15 V Input voltage 4.5 28 V BOOT to PGND electrical characteristics over recommended operating virtual junction temperature range, VCC = 6.5 V, ENABLE = High, CL = 3.3 nF (unless otherwise noted) supply current PARAMETER VCC VCC TEST CONDITIONS Supply voltage range TYP 4.5 Quiescent current V(ENABLE) = LOW, V(ENABLE) = HIGH, VCC =15 V VCC =15 V V(ENABLE) = HIGH, f(SWX) = 200 kHz, C(HIGHDR) = 50 pF, See Note 2 VCC =12 V, BOOTLO grounded, C(LOWDR) = 50 pF, NOTE 2: Ensured by design, not production tested. 4 MIN POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 MAX 15 100 300 3 400 UNIT V µA mA TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 electrical characteristics over recommended operating virtual junction temperature range, VCC = 6.5 V, ENABLE = High, CL = 3.3 nF (unless otherwise noted) (continued) output drivers PARAMETER High-side sink (see Note 3) Peak output current High-side source (see Note 3) L id sink i k Low-side (see Note 3) Low-side L id source (see Note 3) TEST CONDITIONS D t cycle l < 2% Duty 2%, tpw < 100 µs (see Note 2) Duty D t cycle l < 2% 2%, tpw < 100 µs (see Note 2) Duty cycle < 2%, tpw < 100 µs (see Note 2) Duty cycle < 2%, tpw < 100 µs (see Note 2) MIN TYP V(BOOT) – V(BOOTLO) = 4.5 V, V(HIGHDR) = 4 V 0.7 1.1 V(BOOT) – V(BOOTLO) = 6.5 V, V(HIGHDR) = 5 V 1.1 1.5 V(BOOT) – V(BOOTLO) = 12 V, V(HIGHDR) = 10.5 V 2 2.4 V(BOOT) – V(BOOTLO) = 4.5 V, V(HIGHDR) = 0.5V 1.2 1.4 V(BOOT) – V(BOOTLO) = 6.5 V, V(HIGHDR) = 1.5 V 1.3 1.6 V(BOOT) – V(BOOTLO) = 12 V, V(HIGHDR) = 1.5 V 2.3 2.7 1.3 1.8 2 2.5 3 3.5 1.4 1.7 2 2.4 2.5 3 VCC = 4.5 V, V(LOWDR) = 4 V VCC = 6.5 V, V(LOWDR) = 5 V VCC = 12 V, V(LOWDR) = 10.5 V VCC = 4.5 V, VLOWDR)) = 0.5V VCC = 6.5 V, V(LOWDR)) = 1.5 V VCC = 12 V, V(LOWDR0) = 1.5 V V(BOOT) – V(BOOTLO) = 4.5 V, V(HIGHDR)= 0.5 V High-side sink (see Note 3) Output resistance High-side source (see Note 3) V(BOOT) – V(BOOTLO) = 6.5 V, V(HIGHDR) = 0.5 V V(BOOT) – V(BOOTLO) = 12 V, V(HIGHDR) = 0.5 V Low-side source (see Note 3) UNIT A A A A 5 5 Ω 5 V(BOOT) – V(BOOTLO) = 4.5 V, V(HIGHDR) = 4 V 75 V(BOOT) – V(BOOTLO) = 6.5 V, V(HIGHDR)= 6 V 75 V(BOOT) – V(BOOTLO) = 12 V, V(HIGHDR) =11.5 V V(DRV) = 4.5 V, V(LOWDR)= 0.5 V Low-side sink (see Note 3) MAX Ω 75 9 V(DRV) = 6.5 V, V(LOWDR) = 0.5 V V(DRV) = 12 V, V(LOWDR) = 0.5 V 7.5 V(DRV) = 4.5 V, V(LOWDR) = 4 V V(DRV) = 6.5 V, V(LOWDR)= 6 V 75 Ω 6 75 Ω V(DRV) = 12 V, V(LOWDR) = 11.5 V 75 NOTES: 2: Ensured by design, not production tested. 3. The pullup/pulldown circuits of the drivers are bipolar and MOSFET transistors in parallel. The peak output current rating is the combined current from the bipolar and MOSFET transistors. The output resistance is the rDS(on) of the MOSFET transistor when the voltage on the driver output is less than the saturation voltage of the bipolar transistor. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 electrical characteristics over recommended operating virtual junction temperature range, VCC = 6.5 V, ENABLE = High, CL = 3.3 nF (unless otherwise noted) (continued) deadtime control PARAMETER LOWDR DT TEST CONDITIONS High-level input voltage, VIH Over the VCC range (see Note 2) Low-level input voltage, VIL High-level input voltage, VIH Low-level input voltage, VIL NOTE 2: Ensured by design, not production tested. Over the VCC range MIN TYP MAX 0.7VCC 1 0.7VCC UNIT V V 1 V digital control terminals (IN, CROWBAR, SYNC, ENABLE) PARAMETER TEST CONDITIONS High-level input voltage, VIH Over the VCC range Low-level input voltage, VIL MIN TYP MAX 2 UNIT V 1 V switching characteristics over recommended operating virtual junction temperature range, ENABLE = High, CL = 3.3 nF (unless otherwise noted) PARAMETER TEST CONDITIONS HIGHDR output (see Note 2) Rise time LOWDR output (see Note 2) HIGHDR output (see Note 2) LOWDR output (see Note 2) HIGHDR going i low l ((excluding l di deadtime) (see Note 2) Propagation delay time i hi h ((excluding l di LOWDR going high deadtime) (see Note 2) Propagation delay time Driver nonoverlap time LOWDR going i low l ( (excluding l di deadtime) (see Note 2) DT to t LOWDR and d LOWDR tto HIGHDR (see Note 2) MAX 60 V(BOOT) = 12 V, VCC = 4.5 V V(BOOTLO) = 0 V 50 50 V(BOOT) = 4.5 V, V(BOOT) = 6.5 V, 30 V(BOOTLO) = 0 V V(BOOTLO) = 0 V V(BOOTLO) = 0 V ns 50 40 ns 40 40 30 ns 30 V(BOOT) = 4.5 V, V(BOOT) = 6.5 V, V(BOOTLO) = 0 V V(BOOTLO) = 0 V 95 V(BOOT) = 12 V, V(BOOT) = 4.5 V, V(BOOTLO) = 0 V 70 V(BOOTLO) = 0 V V(BOOTLO) = 0 V 80 V(BOOTLO) = 0 V 60 80 70 VCC = 4.5 V VCC = 6.5 V VCC = 12 V VCC = 4.5 V VCC = 6.5 V VCC = 12 V POST OFFICE BOX 655303 ns 30 VCC = 6.5 V VCC = 12 V V(BOOT) = 6.5 V, V(BOOT) = 12 V, UNIT 40 VCC = 6.5 V VCC = 12 V NOTE 2: Ensured by design, not production tested. 6 TYP V(BOOTLO) = 0 V V(BOOTLO) = 0 V V(BOOT) = 12 V, VCC = 4.5 V Fall time MIN V(BOOT) = 4.5 V, V(BOOT) = 6.5 V, • DALLAS, TEXAS 75265 ns ns 80 70 ns 60 40 170 25 135 15 85 ns TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 TYPICAL CHARACTERISTICS FALL TIME vs SUPPLY VOLTAGE RISE TIME vs SUPPLY VOLTAGE 50 50 CL = 3.3 nF TJ = 25 °C 45 40 40 t f – Fall Time – ns t r – Rise Time – ns CL = 3.3 nF TJ = 25 °C 45 High Side 35 30 Low Side 25 35 High Side 30 25 20 20 15 15 10 Low Side 10 4 5 6 7 9 10 11 12 13 8 VCC – Supply Voltage – V 14 15 4 6 5 Figure 1 FALL TIME vs JUNCTION TEMPERATURE 50 50 VCC = 6.5 V CL = 3.3 nF 45 VCC = 6.5 V CL = 3.3 nF 40 40 t f – Fall Time – ns t r – Rise Time – ns High Side 35 30 Low Side 25 High Side 35 30 25 Low Side 20 20 15 15 10 –50 14 15 Figure 2 RISE TIME vs JUNCTION TEMPERATURE 45 8 7 9 10 11 12 13 VCC – Supply Voltage – V –25 0 25 50 75 100 125 10 –50 –25 0 25 50 75 100 125 TJ – Junction Temperature – °C TJ – Junction Temperature – °C Figure 3 Figure 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 TYPICAL CHARACTERISTICS HIGH-TO-LOW PROPAGATION DELAY TIME vs SUPPLY VOLTAGE, HIGH TO LOW LEVEL 150 t PHL – High-to-Low Propagation Delay Time – ns t PLH – Low-to-High Propagation Delay Time – ns LOW-TO-HIGH PROPAGATION DELAY TIME vs SUPPLY VOLTAGE, LOW TO HIGH LEVEL CL = 3.3 nF TJ = 25 °C 140 130 120 110 100 90 80 70 60 Low Side 50 40 30 20 4 5 6 7 9 10 11 12 13 8 VCC – Supply Voltage – V 14 15 150 CL = 3.3 nF TJ = 25 °C 140 130 120 110 100 90 80 70 High Side 60 50 40 Low Side 30 20 4 5 6 8 7 9 10 11 12 13 VCC – Supply Voltage – V Figure 5 Figure 6 150 130 VCC = 6.5 V CL = 3.3 nF 120 110 100 High Side 90 80 70 60 Low Side 50 40 30 20 –50 HIGH-TO-LOW PROPAGATION DELAY TIME vs JUNCTION TEMPERATURE t PHL – High-to-Low Propagation Delay Time – ns t PLH – Low-to-High Propagation Delay Time – ns LOW-TO-HIGH PROPAGATION DELAY TIME vs JUNCTION TEMPERATURE 140 –25 25 75 0 50 100 TJ – Junction Temperature – °C 125 150 140 130 VCC = 6.5 V CL = 3.3 nF 120 110 100 90 High Side 80 70 60 50 Low Side 40 30 20 –50 –25 0 25 Figure 8 POST OFFICE BOX 655303 50 75 TJ – Junction Temperature – °C Figure 7 8 14 15 • DALLAS, TEXAS 75265 100 125 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 TYPICAL CHARACTERISTICS DRIVER-OUTPUT FALL TIME vs LOAD CAPACITANCE DRIVER-OUTPUT RISE TIME vs LOAD CAPACITANCE 1000 1000 VCC = 6.5 V TJ = 25 °C t f – Fall Time – ns t r – Rise Time – ns VCC = 6.5 V TJ = 25 °C 100 High Side Low Side 10 1 0.01 1 0.1 10 100 High Side Low Side 10 1 0.01 100 CL – Load Capacitance – nF 10 Figure 9 Figure 10 SUPPLY CURRENT vs SUPPLY VOLTAGE SUPPLY CURRENT vs SUPPLY VOLTAGE 100 25 6000 TJ = 25 °C CL = 50 pF 5500 TJ = 25 °C CL = 50 pF 5000 20 4500 ICC – Supply Current – mA ICC – Supply Current – µ A 1 0.1 CL – Load Capacitance – nF 500 kHz 4000 300 kHz 3500 200 kHz 3000 100 kHz 50 kHz 25 kHz 2500 2000 1500 1000 2 MHz 15 10 1 MHz 5 500 0 0 4 6 8 10 12 14 16 4 VCC – Supply Voltage – V 6 8 10 12 14 16 VCC – Supply Voltage – V Figure 11 Figure 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 TYPICAL CHARACTERISTICS PEAK SOURCE CURRENT vs DRIVE VOLTAGE PEAK SINK CURRENT vs DRIVE VOLTAGE 4 4 TJ = 25 °C TJ = 25 °C 3.5 3 3 Low Side Peak Sink Current – A Peak Source Current – A 3.5 2.5 2 High Side 1.5 Low Side 2.5 2 High Side 1.5 1 1 0.5 0.5 0 0 4 6 8 10 12 14 16 4 6 VCC – Supply Voltage – V Figure 13 14 16 2.00 TJ = 25 °C VCC = 6.5 V V IT – Input Threshold Voltage – V V IT – Input Threshold Voltage – V 12 INPUT THRESHOLD VOLTAGE vs JUNCTION TEMPERATURE 2.00 1.80 1.60 1.40 1.20 6.00 8.00 10.00 12.00 14.00 16.00 1.80 1.60 1.40 1.20 1.00 –50.00 –25.00 0.00 25.00 50.00 75.00 100.00 125.00 TJ – Junction Temperature – °C VCC – Supply Voltage – V Figure 15 10 10 Figure 14 INPUT THRESHOLD VOLTAGE vs SUPPLY VOLTAGE 1.00 4.00 8 VCC – Supply Voltage – V Figure 16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 APPLICATION INFORMATION Figure 17 shows the circuit schematic of a 100-kHz synchronous-buck converter implemented with a TL5001A pulse-width-modulation (PWM) controller and a TPS2835 driver. The converter operates over an input range from 4.5 V to 12 V and has a 3.3-V output. The circuit can supply 3 A continuous load. The converter achieves an efficiency of 94% for VIN = 5 V, Iload=1 A, and 93% for VIN = 5 V, Iload = 3 A. VIN + C10 100 µF C5 100 µF + R1 1 kΩ U1 TPS2835 1 2 3 4 5 6 7 BOOT ENABLE 14 13 IN NC 12 CROWBAR HIGHDR 11 BOOTLO NC 10 LOWDR SYNC 9 NC DT VCC 8 PGND C15 1.0 µF R6 1 MΩ Q1 Si4410 Q2 Si4410 GND OUT 3.3 V C7 100 µF + C12 100 µF + C6 1000 pF C3 0.0022 µF U2 TL5001A 2 C2 VCC 0.033 µF R2 1.6 kΩ COMP 3 6 DTC FB 4 5 SCP RT 7 R8 121 kΩ C13 10 µF RTN C8 0.1 µF 1 L1 27 µH R7 3.3 Ω R11 4.7 Ω C14 1 µF C9 0.22 µF C11 0.47 µF R5 0Ω C4 0.022 µF R3 180 Ω R4 2.32 kΩ GND C1 1 µF 8 R9 90.9 kΩ R10 1.0 kΩ Figure 17. 3.3-V 3-A Synchronous-Buck Converter Circuit POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 APPLICATION INFORMATION Great care should be taken when laying out the pc board. The power-processing section is the most critical and will generate large amounts of EMI if not properly configured. The junction of Q1, Q2, and L1 should be very tight. The connection from Q1 drain to the positive sides of C5, C10, and C11 and the connection from Q2 source to the negative sides of C5, C10, and C11 should be as short as possible. The negative terminals of C7 and C12 should also be connected to Q2 source. Next, the traces from the MOSFET driver to the power switches should be considered. The BOOTLO signal from the junction of Q1 and Q2 carries the large gate drive current pulses and should be as heavy as the gate drive traces. The bypass capacitor (C14) should be tied directly across VCC and PGND. The next most sensitive node is the FB node on the controller (terminal 4 on the TL5001A). This node is very sensitive to noise pick-up and should be isolated from the high-current power stage and be as short as possible. The ground around the controller and low-level circuitry should be tied to the power ground as the output. If these three areas are properly laid out, the rest of the circuit should not have other EMI problems and the power supply will be relatively free of noise. 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 MECHANICAL DATA D (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PIN SHOWN 0.050 (1,27) 0.020 (0,51) 0.014 (0,35) 14 0.010 (0,25) M 8 0.008 (0,20) NOM 0.244 (6,20) 0.228 (5,80) 0.157 (4,00) 0.150 (3,81) Gage Plane 0.010 (0,25) 1 7 0°– 8° A 0.044 (1,12) 0.016 (0,40) Seating Plane 0.069 (1,75) MAX 0.010 (0,25) 0.004 (0,10) PINS ** 0.004 (0,10) 8 14 16 A MAX 0.197 (5,00) 0.344 (8,75) 0.394 (10,00) A MIN 0.189 (4,80) 0.337 (8,55) 0.386 (9,80) DIM 4040047 / D 10/96 NOTES: A. B. C. D. All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion, not to exceed 0.006 (0,15). Falls within JEDEC MS-012 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 TPS2834, TPS2835 SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEADTIME CONTROL SLVS223 – NOVEMBER 1999 MECHANICAL DATA PWP (R-PDSO-G**) PowerPAD PLASTIC SMALL-OUTLINE PACKAGE 20-PIN SHOWN 0,30 0,19 0,65 20 0,10 M 11 Thermal Pad (See Note D) 4,50 4,30 0,15 NOM 6,60 6,20 Gage Plane 1 10 0,25 A 0°– 8° 0,75 0,50 Seating Plane 0,15 0,05 1,20 MAX PINS ** 0,10 14 16 20 24 28 A MAX 5,10 5,10 6,60 7,90 9,80 A MIN 4,90 4,90 6,40 7,70 9,60 DIM 4073225/E 03/97 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusions. The package thermal performance may be enhanced by bonding the thermal pad to an external thermal plane. This pad is electrically and thermally connected to the backside of the die and possibly selected leads. E. Falls within JEDEC MO-153 PowerPAD is a trademark of Texas Instruments Incorporated. 14 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 1999, Texas Instruments Incorporated