www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 ± FEATURES DESCRIPTION D D D D D ±3-A Maximum Output Current The DRV591 is a high-efficiency, high-current power amplifier ideal for driving a wide variety of thermoelectric cooler elements in systems powered from 2.8 V to 5.5 V. PWM operation and low output stage on-resistance significantly decrease power dissipation in the amplifier. D D D D Two Selectable Switching Frequencies Low Supply Voltage Operation: 2.8 V to 5.5 V High Efficiency Generates Less Heat Over-Current and Thermal Protection Fault Indicators for Over-Current, Thermal and Under-Voltage Conditions The DRV591 is internally protected against thermal and current overloads. Logic-level fault indicators signal when the junction temperature has reached approximately 130°C to allow for system-level shutdown before the amplifier’s internal thermal shutdown circuitry activates. The fault indicators also signal when an over-current event has occurred. If the over-current circuitry is tripped, the DRV591 automatically resets (see application information section for more details). Internal or External Clock Sync PWM Scheme Optimized for EMI 9×9 mm PowerPAD Quad Flatpack APPLICATIONS The PWM switching frequency may be set to 500 kHz or 100 kHz depending on system requirements. To eliminate external components, the gain is fixed at approximately 2.3 V/V. D Thermoelectric Cooler (TEC) Driver D Laser Diode Biasing VDD OUT+ OUT+ PVDD PVDD PVDD FREQ INT/EXT PGND IN– PGND SHUTDOWN OUT– 10 µH FAULT1 FAULT0 10 µF 1 µF To TEC or Laser Diode Anode OUT– Shutdown Control PGND IN+ OUT– 1 kΩ PGND AREF OUT– 1 kΩ COSC PVDD 1 µF PGND PVDD 220 pF PGND ROSC PVDD DC Control Voltage 10 µH OUT+ AGND (Connect to PowerPAD) FAULT0 120 kΩ AVDD FAULT1 1 µF OUT+ 1 µF 10 µF 10 µF To TEC or Laser Diode Cathode 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. PowerPAD is a trademark of Texas Instruments. ! "#$ ! %#&'" ( $) (#" ! " !%$"" ! %$ *$ $! $+! ! #$ ! ! (( , -) (#" %"$!!. ($! $"$!!'- "'#($ $! . '' %$ $!) Copyright 2002, Texas Instruments Incorporated www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. ORDERING INFORMATION TA PowerPAD QUAD FLATPACK (VFP) DRV591VFP(1) –40°C to 85°C (1) This package is available taped and reeled. To order this packaging option, add an R suffix to the part number (e.g., DRV591VFPR). ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range unless otherwise noted(1) Supply voltage, AVDD, PVDD Input voltage, VI Output current, IO (FAULT0, FAULT1) Continuous total power dissipation DRV591 UNIT –0.3 to 5.5 V –0.3 to VDD + 0.3 V 1 mA See Dissipation Rating Table Operating free-air temperature range, TA –40 to 85 °C Operating junction temperature range, TJ –40 to 150 °C Storage temperature range, Tstg –65 to 165 °C (1) 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. RECOMMENDED OPERATING CONDITIONS ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑ ÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑ ÑÑ ÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑ Ñ ÑÑ ÑÑÑ Ñ ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ ÑÑÑÑÑ ÑÑÑ MIN Supply voltage, AVDD, PVDD 2.8 High-level input voltage, VIH FREQ, INT/EXT, SHUTDOWN, COSC Low-level input voltage, VIL FREQ, INT/EXT, SHUTDOWN, COSC Operating free-air temperature, TA PACKAGE ΘJA(1) (°C/W) ΘJC (°C/W) TA = 25°C POWER RATING VFP 29.4 1.2 4.1 W (1) This data was taken using 2 oz trace and copper pad that is soldered directly to a JEDEC standard 4-layer 3 in × 3 in PCB. 2 5.5 2 –40 PACKAGE DISSIPATION RATINGS MAX UNIT V V 0.8 V 85 °C www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 ELECTRICAL CHARACTERISTICS over operating free-air temperature range unless otherwise noted PARAMETER TEST CONDITIONS |VOO| Output offset voltage (measured differentially) |IIH| High-level input current |IIL| Low-level input current Vn Integrated output noise voltage VICM Common mode voltage range Common-mode Av Closed-loop voltage gain VI = VDD/2, VDD = 5.5V, IO = 0 A VI = VDD VDD = 5.5V, f = <1 Hz to 10 kHz VI = 0 V MIN rDS(on) DS( ) VDD = 5 V VDD = 3.3 V UNIT 100 mV 1 µA 1 µA µV 1.2 3.8 1.2 2.1 2.1 2.34 2.6 60 IO = ±1 A, IO = ±3 A, Voltage output (measured differentially) Drain source on-state Drain-source on state resistance 25 60 95 25 65 95 25 80 140 TA = 25°C 25 90 140 Low side 4.87 Sinking 200 µA External clock frequency range Iq Quiescent current Iq(SD) Quiescent current in shutdown mode Output resistance in shutdown 0.1 For 500 kHz operation 225 250 275 For 100 kHz operation 45 50 55 VDD = 5 V, No load or filter VDD = 3.3 V, No load or filter 2 6.2 12 2 4.6 8 VDD = 5 V, SHUTDOWN = 0.8 V SHUTDOWN = 0.8 V 0 0.1 50 2 1.7 2.8 1.6 2.6 Input impedance (IN+, IN–) mΩ V kHz mA µA kΩ Power-off threshold FAULT0 active mΩ A Power-on threshold Thermal trip point V/V V 4.61 3 Status flag output pins (FAULT0, FAULT1) Fault active (open drain output) V kHz rds(on) = 65 mΩ, VDD = 5 V rds(on) = 65 mΩ, VDD = 5 V High side VDD = 5 V, IO = 4 A, TA = 25°C Low side High side VDD = 3.3 V, IO = 4 A, Maximum continuous current output ZI MAX 14 40 Full power bandwidth VO TYP V V 130 °C 100 kΩ PIN ASSIGNMENTS FREQ INT/EXT PVDD PVDD PVDD OUT+ OUT+ OUT+ VFP PACKAGE (TOP VIEW) 32 31 30 29 28 27 26 25 1 24 2 23 22 3 4 PowerPAD 5 21 20 7 19 18 8 17 6 OUT+ PGND PGND PGND PGND PGND PGND OUT– 9 10 11 12 13 14 15 16 FAULT1 FAULT0 PVDD PVDD PVDD OUT– OUT– OUT– AVDD AGND ROSC COSC AREF IN+ IN– SHUTDOWN 3 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 Terminal Functions TERMINAL I/O DESCRIPTION NAME NO. AGND 2 AREF 5 O Connect 1 µF capacitor to ground for AREF voltage filtering AVDD 1 I Analog power supply COSC 4 I Connect capacitor to ground to set oscillation frequency (220 pF for 500 kHz, 1 nF for 100 kHz) when the internal oscillator is selected; connect clock signal when an external oscillator is used FAULT0 10 O Fault flag 0, low when active open drain output (see application information) FAULT1 9 O Fault flag 1, high when active open drain output (see application information) FREQ 32 I Selects 500 kHz switching frequency when a TTL logic low is applied to this terminal; selects 100 kHz switching frequency when a TTL logic high is applied IN– 7 I Negative differential input IN+ 6 I Positive differential input INT/EXT 31 I Selects the internal oscillator when a TTL logic high is applied to this terminal; selects the use of an external oscillator when a TTL logic low is applied to this terminal OUT– 14, 15, 16, 17 O Negative bridge-tied load (BTL) output (4 pins) OUT+ 24, 25, 26, 27 O Positive bridge-tied load (BTL) output (4 pins) PGND 18, 19, 20, 21, 22, 23 PVDD 11, 12, 13, 28, 29, 30 I High-current power supply (6 pins) ROSC 3 I Connect 120-kΩ resistor to AGND to set oscillation frequency (either 500 kHz or 100 kHz). Not needed if an external clock is used. SHUTDOWN 8 I Places the amplifier in shutdown mode when a TTL logic low is applied to this terminal; places the amplifier in normal operation when a TTL logic high is applied 4 Analog ground High-current ground (6 pins) www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 FUNCTIONAL BLOCK DIAGRAM AVDD AGND AVDD PVDD IN– R + _ 2.34 × R _ + Gate Drive OUT– _ + _ + + _ PGND PVDD IN+ R 2.34 × R + _ OUT+ Gate Drive PGND SHUTDOWN INT/EXT FREQ COSC ROSC AREF TTL Input Buffer Biases and References Ramp Generator Start-Up Protection Logic Thermal OC Detect VDDok FAULT0 FAULT1 5 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 TYPICAL CHARACTERISTICS TABLE OF GRAPHS FIGURE Efficiency rDS(on) Iq PSRR vs Load resistance 2, 3 vs Supply voltage 4 vs Free-air temperature 5 vs Free-air temperature 6 Supply current vs Supply voltage 7 Power supply rejection ratio vs Frequency Drain-source Drain source on-state on state resistance 8, 9 Closed loop response 10, 11 vs Output voltage IO Maximum output current VIO Input offset voltage vs Ambient temperature Common-mode input voltage TEST SET-UP FOR GRAPHS The LC output filter used in Figures 2, 3, 8, and 9 is shown below. L1 OUT+ C1 RL L2 OUT– C2 L1, L2 = 10 µH (part number: CDRH104R, manufacturer: Sumida) C1, C2 = 10 µF (part number: ECJ-4YB1C106K, manufacturer: Panasonic) Figure 1. LC Output Filter 6 12 13 14, 15 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 TYPICAL CHARACTERISTICS EFFICIENCY vs LOAD RESISTANCE EFFICIENCY vs LOAD RESISTANCE 100 100 90 90 PO = 2 W 80 70 PO = 0.5 W 60 50 40 50 40 30 20 20 VDD = 5 V fS = 500 kHz PO = 0.25 W 60 30 10 VDD = 3.3 V fS = 500 kHz 10 0 0 1 2 3 4 5 6 7 8 RL – Load Resistance – Ω 9 1 10 Figure 2 IO = 1 A TA = 25°C 250 Total 150 Low Side 100 High Side 50 0 2.7 3.1 3.5 3.9 4.3 4.7 VDD – Supply Voltage – V Figure 4 3 4 5 6 7 8 RL – Load Resistance – Ω 9 10 DRAIN-SOURCE ON-STATE RESISTANCE vs FREE-AIR TEMPERATURE rDS(on) – Drain-Source On-State Resistance – mΩ 300 200 2 Figure 3 DRAIN-SOURCE ON-STATE RESISTANCE vs SUPPLY VOLTAGE rDS(on) – Drain-Source On-State Resistance – mΩ PO = 1 W 70 PO = 0.5 W Efficiency – % Efficiency – % 80 PO = 1 W 5.1 5.5 300 250 VDD = 5 V IO = 1 A VFP Package 200 Total 150 Low Side 100 High Side 50 0 –40 –15 10 35 60 TA – Free-Air Temperature – °C 85 Figure 5 7 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 TYPICAL CHARACTERISTICS SUPPLY CURRENT vs SUPPLY VOLTAGE 300 10 VDD = 3.3 V IO = 1 A VFP Package 250 No Load 9 8 Total Iq – Supply Current – mA rDS(on) – Drain-Source On-State Resistance – mΩ DRAIN-SOURCE ON-STATE RESISTANCE vs FREE-AIR TEMPERATURE 200 150 Low Side 100 High Side 7 6 5 4 3 2 50 1 0 –40 –15 10 35 60 0 2.7 85 TA – Free-Air Temperature – °C 3.1 3.5 5.5 –20 VDD = 5 V fS = 500 kHz RL = 1 Ω Vripple = 100 mVpp PSRR – Power Supply Rejection Ratio – dB PSRR – Power Supply Rejection Ratio – dB 5.1 POWER SUPPLY REJECTION RATIO vs FREQUENCY –20 –40 –50 –60 –70 100 1k 10k f – Frequency – Hz Figure 8 8 4.7 Figure 7 POWER SUPPLY REJECTION RATIO vs FREQUENCY –80 10 4.3 VDD – Supply Voltage – V Figure 6 –30 3.9 100k –30 VDD = 3.3 V fS = 500 kHz RL = 1 Ω Vripple = 100 mVpp –40 –50 –60 –70 –80 10 100 1k 10k f – Frequency – Hz Figure 9 100k www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 TYPICAL CHARACTERISTICS CLOSED LOOP RESPONSE 4 10 Phase 0 –10 3 –30 2 –40 Phase – ° Gain – V/V –20 Gain –50 1 –60 VDD = 5 V No Load –70 0 10 100 1k 10k f – Frequency – Hz –80 100k Figure 10 CLOSED LOOP RESPONSE 10 4 0 Phase –10 3 –30 2 –40 Phase – ° Gain – V/V –20 Gain –50 1 –60 VDD = 3.3 V No Load 0 10 100 –70 1k 10k f – Frequency – Hz –80 100k Figure 11 9 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 TYPICAL CHARACTERISTICS MAXIMUM OUTPUT CURRENT vs OUTPUT VOLTAGE MAXIMUM OUTPUT CURRENT vs AMBIENT TEMPERATURE 3.5 3.5 I O – Maximum Output Current – A I O – Maximum Output Current – A 3 TJ = 100°C 2.5 TJ = 85°C 2 TJ = 125°C 1.5 1 VDD = 5 V TA = 25°C VFP Package 0.5 0 0 1 2 3 VO – Output Voltage – V 4 3 2.5 2 1.5 1 0.5 TJ ≤ 125°C VFP Package 0 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 TA – Ambient Temperature – °C 5 Figure 12 Figure 13 INPUT OFFSET VOLTAGE vs COMMON-MODE INPUT VOLTAGE INPUT OFFSET VOLTAGE vs COMMON-MODE INPUT VOLTAGE 10 19 8 VIO – Input Offset Voltage – mV VIO – Input Offset Voltage – mV 9 20 VDD = 5 V No Load 7 6 5 4 3 2 1 0 1.2 18 17 16 15 14 13 12 11 1.6 2.0 2.4 2.8 3.2 VIC – Common-Mode Input Voltage – V Figure 14 10 VDD = 3.3 V No Load 3.6 3.8 10 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 VIC – Common-Mode Input Voltage – V Figure 15 2.1 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 APPLICATION INFORMATION VDD OUT+ OUT+ OUT+ PVDD PVDD To TEC or Laser Diode Anode PGND IN+ PGND IN– PGND SHUTDOWN OUT– 10 µF OUT– PGND AREF OUT– Shutdown Control COSC OUT– 1 kΩ PGND PVDD 1 kΩ PGND ROSC PVDD 1 µF 10 µH OUT+ PVDD 220 pF DC Control Voltage 1 µF AGND (Connect to PowerPAD) FAULT1 120 kΩ PVDD FREQ AVDD FAULT0 1 µF INT/EXT 10 µF 10 µH FAULT1 FAULT0 To TEC or Laser Diode Cathode 10 µF 1 µF Figure 16. Typical Application Circuit OUTPUT FILTER CONSIDERATIONS TEC element manufacturers provide electrical specifications for maximum dc current and maximum output voltage for each particular element. The maximum ripple current, however, is typically only recommended to be less than 10% with no reference to the frequency components of the current. The maximum temperature differential across the element, which decreases as ripple current increases, may be calculated with the following equation: DT + 1 ǒ1 ) N2Ǔ DT max designed for the worst-case conditions during operation, which is typically when the differential output is at 50% duty cycle. The following section serves as a starting point for the design, and any calculations should be confirmed with a prototype circuit in the lab. Any filter should always be placed as close as possible to the DRV591 to reduce EMI. L OUT+ C (1) TEC R L OUT– Where: ∆T = actual temperature differential ∆Tmax = maximum temperature differential (specified by manufacturer) N = ratio of ripple current to dc current According to this relationship, a 10% ripple current reduces the maximum temperature differential by 1%. An LC network may be used to filter the current flowing to the TEC to reduce the amount of ripple and, more importantly, protect the rest of the system from any electromagnetic interference (EMI). C Figure 17. LC Output Filter OUT+ or OUT– L C TEC R FILTER COMPONENT SELECTION The LC filter, which may be designed from two different perspectives, both described below, helps estimate the overall performance of the system. The filter should be Figure 18. LC Half-Circuit Equivalent (for DRV591 Only) 11 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 LC FILTER IN THE FREQUENCY DOMAIN The transfer function for a 2nd order low-pass filter (Figures 17 and 18) is shown in equation (2): H LP(jw) + 1 ǒ Ǔ – ww 0 2 For relatively small capacitors (less than 22 µF) with very low equivalent series resistance (ESR, less than 10 mΩ), such as ceramic capacitors, the following equation (5) may be used to estimate the ripple voltage on the capacitor due to the change in charge: (2) ǒǓ f 2 DV + p ǒ1–DǓ o C 2 fs jw ) 1 w )1 Q 0 fo + For the DRV591, the differential output switching frequency is typically selected to be 500 kHz. The resonant frequency for the filter is typically chosen to be at least one order of magnitude lower than the switching frequency. Equation (2) may then be simplified to give the following magnitude equation (3). These equations assume the use of the filter in Figure 17. fo + ǒǓ fs fo (3) 1 2p ǸLC The average TEC element has a resistance of 1.5 Ω, so the ripple current through the TEC is approximately 3.4 mA. At the 3-A maximum output current of the DRV591, this 5.4 mA corresponds to 0.11% ripple current, causing less than 0.0001% reduction of the maximum temperature differential of the TEC element (see equation 1). LC FILTER IN THE TIME DOMAIN The ripple current of an inductor may be calculated using equation (4): ǒVO–V TECǓDTs (4) L D + duty cycle (0.5 worst case) T s + 1ńfs + 1ń500 kHz For VO = 5 V, VTEC = 2.5 V, and L = 10 µH, the inductor ripple current is 250 mA. To calculate how much of that ripple current flows through the TEC element, however, the properties of the filter capacitor must be considered. 1 2p ǸLC For larger capacitors (greater than 22 µF) with relatively high ESR (greater than 100 mΩ), such as electrolytic capacitors, the ESR dominates over the chargingdischarging of the capacitor. The following simple equation (6) may be used to estimate the ripple voltage: DV If L=10 µH and C=10 µF, the cutoff frequency is 15.9 kHz, which corresponds to –60 dB of attenuation at the 500 kHz switching frequency. For VDD = 5 V, the amount of ripple voltage at the TEC element is approximately 5 mV. 12 TEC For L = 10 µH and C = 10 µF, the cutoff frequency, fo, is 15.9 kHz. For worst case duty cycle of 0.5 and VTEC=2.5 V, the ripple voltage on the capacitors is 6.2 mV. The ripple current may be calculated by dividing the ripple voltage by the TEC resistance of 1.5 Ω, resulting in a ripple current through the TEC element of 4.1 mA. Note that this is similar to the value calculated using the frequency domain approach. f s + 500 kHz (DRV591 switching frequency) DI + L V f s + 500 kHz w + DRV591 switching frequency + –40 log (5) D + duty cycle w0 + 1 ǸLC Q + quality factor ŤH LPŤdB 2 C + DIL R (6) ESR DI L + inductor ripple current R ESR + filter capacitor ESR For a 100 µF electrolytic capacitor, an ESR of 0.1 Ω is common. If the 10 µH inductor is used, delivering 250 mA of ripple current to the capacitor (as calculated above), then the ripple voltage is 25 mV. This is over ten times that of the 10 µF ceramic capacitor, as ceramic capacitors typically have negligible ESR. SWITCHING FREQUENCY CONFIGURATION: OSCILLATOR COMPONENTS ROSC AND COSC AND FREQ OPERATION The onboard ramp generator requires an external resistor and capacitor to set the oscillation frequency. The frequency may be either 500 kHz or 100 kHz by selecting the proper capacitor value and by holding the FREQ pin either low (500 kHz) or high (100 kHz). Table 1 shows the values required and FREQ pin configuration for each switching frequency. Table 1. Frequency Configuration Options SWITCHING FREQUENCY ROSC COSC FREQ 500 kHz 120 kΩ 220 pF LOW (GND) 100 kHz 120 kΩ 1 nF HIGH (VDD) www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 For proper operation, the resistor ROSC should have 1% tolerance while capacitor COSC should be a ceramic type with 10% tolerance. Both components should be grounded to AGND, which should be connected to PGND at a single point, typically where power and ground are physically connected to the printed-circuit board. EXTERNAL CLOCKING OPERATION To synchronize the switching to an external clock signal, pull the INT/EXT terminal low, and drive the clock signal into the COSC terminal. This clock signal must be from 10% to 90% duty cycle and meet the voltage requirements specified in the electrical specifications table. Since the DRV591 includes an internal frequency doubler, the external clock signal must be approximately 250 kHz. Deviations from the 250 kHz clock frequency are allowed and are specified in the electrical characteristic table. The resistor connected from ROSC to ground may be omitted from the circuit in this mode of operation—the source is disconnected internally. INPUT CONFIGURATION: DIFFERENTIAL AND SINGLE-ENDED If a differential input is used, it should be biased around the midrail of the DRV591 and must not exceed the common-mode input range of the input stage (see the operating characteristics at the beginning of the data sheet). The most common configuration employs a single-ended input. The unused input should be tied to VDD/2, which may be simply accomplished with a resistive voltage divider. For the best performance, the resistor values chosen should be at least 100 times lower than the input resistance of the DRV591. This prevents the bias voltage at the unused input from shifting when the signal input is applied. A small ceramic capacitor should also be placed from the input to ground to filter noise and keep the voltage stable. An op amp configured as a buffer may also be used to set the voltage at the unused input. FIXED INTERNAL GAIN The differential output voltage may be calculated using equation (7): V O +V ǒ Ǔ –V + A v V IN)–V IN– OUT) OUT– (7) AV is the voltage gain, which is fixed internally at 2.34 V/V. The maximum and minimum ratings are provided in the electrical specification table at the beginning of the data sheet. POWER SUPPLY DECOUPLING To reduce the effects of high-frequency transients or spikes, a small ceramic capacitor, typically 0.1 µF to 1 µF, should be placed as close to each set of PVDD pins of the DRV591 as possible. For bulk decoupling, a 10 µF to 100 µF tantalum or aluminum electrolytic capacitor should be placed relatively close to the DRV591. AREF CAPACITOR The AREF terminal is the output of an internal mid-rail voltage regulator used for the onboard oscillator and ramp generator. The regulator may not be used to provide power to any additional circuitry. A 1 µF ceramic capacitor must be connected from AREF to AGND for stability (see oscillator components above for AGND connection information). SHUTDOWN OPERATION The DRV591 includes a shutdown mode that disables the outputs and places the device in a low supply current state. The SHUTDOWN pin may be controlled with a TTL logic signal. When SHUTDOWN is held high, the device operates normally. When SHUTDOWN is held low, the device is placed in shutdown. The SHUTDOWN pin must not be left floating. If the shutdown feature is unused, the pin may be connected to VDD. FAULT REPORTING The DRV591 includes circuitry to sense three faults: D Overcurrent D Undervoltage D Overtemperature These three fault conditions are decoded via the FAULT1 and FAULT0 terminals. Internally, these are open-drain outputs, so an external pull-up resistor of 5 kΩ or greater is required. Table 2. Fault Indicators FAULT1 FAULT0 0 0 Overcurrent 0 1 Undervoltage 1 0 Overtemperature 1 1 Normal operation The over-current fault is reported when the output current exceeds four amps. As soon as the condition is sensed, the over-current fault is set and the outputs go into a high-impedance state for approximately 3 µs to 5 µs (500 kHz operation). After 3 µs to 5 µs, the outputs are re-enabled. If the over-current condition has ended, the fault is cleared and the device resumes normal operation. If the over-current condition still exists, the above sequence repeats. The under-voltage fault is reported when the operating voltage is reduced below 2.8 V. This fault is not latched, so as soon as the power-supply recovers, the fault is cleared and normal operation resumes. During the under-voltage condition, the outputs go into a high-impedance state to prevent over-dissipation due to increased rDS(on). 13 www.ti.com SLOS389A – NOVEMBER 2001– REVISED MAY 2002 The over-temperature fault is reported when the junction temperature exceeds 130°C. The device continues operating normally until the junction temperature reaches 190°C, at which point the IC is disabled to prevent permanent damage from occurring. The system’s controller must reduce the power demanded from the DRV591 once the over-temperature flag is set, or else the device switches off when it reaches 190°C. This fault is not latched; once the junction temperature drops below 130°C, the fault is cleared, and normal operation resumes. used to route the currents. Wide traces (100 mils) should be used for PGND while narrow traces (15 mils) should be used for AGND. 2. Power supply decoupling. A small 0.1 µF to 1 µF ceramic capacitor should be placed as close to each set of PVDD pins as possible, connecting from PVDD to PGND. A 0.1 µF to 1 µF ceramic capacitor should also be placed close to the AVDD pin, connecting from AVDD to AGND. A bulk decoupling capacitor of at least 10 µF, preferably ceramic, should be placed close to the DRV591, from PVDD to PGND. If power supply lines are long, additional decoupling may be required. 3. Power and output traces. The power and output traces should be sized to handle the desired maximum output current. The output traces should be kept as short as possible to reduce EMI, i.e., the output filter should be placed as close to the DRV591 outputs as possible. 4. PowerPAD. The DRV591 in the Quad Flatpack package uses TI’s PowerPAD technology to enhance the thermal performance. The PowerPAD is physically connected to the substrate of the DRV591 silicon, which is connected to AGND. The PowerPAD ground connection should therefore be kept separate from PGND as described above. The pad underneath the AGND pin may be connected underneath the device to the PowerPAD ground connection for ease of routing. For additional information on PowerPAD PCB layout, refer to the PowerPAD Thermally Enhanced Package application note, TI literature number SLMA002. 5. Thermal performance. For proper thermal performance, the PowerPAD must be soldered down to a thermal land, as described in the PowerPAD Thermally Enhanced Package application note, TI literature number SLMA002. In addition, at high current levels (greater than 2 A) or high ambient temperatures (greater than 25°C), an internal plane may be used for heat sinking. The vias under the PowerPAD should make a solid connection, and the plane should not be tied to ground except through the PowerPAD connection, as described above. POWER DISSIPATION AND MAXIMUM AMBIENT TEMPERATURE Though the DRV591 is much more efficient than traditional linear solutions, the power drop across the on-resistance of the output transistors does generate some heat in the package, which may be calculated as shown in equation (8): P DISS ǒ OUTǓ + I (8) 2 r DS(on), total For example, at the maximum output current of 3 A through a total on-resistance of 130 mΩ (at TJ = 25°C), the power dissipated in the package is 1.17 W. Calculate the maximum ambient temperature using equation (9): ǒ T A + TJ * θ JA P DISS Ǔ (9) PRINTED-CIRCUIT BOARD (PCB) LAYOUT CONSIDERATIONS Since the DRV591 is a high-current switching device, a few guidelines for the layout of the printed-circuit board (PCB) must be considered: 1. 14 Grounding. Analog ground (AGND) and power ground (PGND) must be kept separated, ideally back to where the power supply physically connects to the PCB, minimally back to the bulk decoupling capacitor (10 µF ceramic minimum). Furthermore, the PowerPAD ground connection should be made to AGND, not PGND. Ground planes are not recommended for AGND or PGND, traces should be PACKAGE OPTION ADDENDUM www.ti.com 13-May-2014 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) DRV591VFP ACTIVE HLQFP VFP 32 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 85 DRV591 DRV591VFPG4 ACTIVE HLQFP VFP 32 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 85 DRV591 DRV591VFPR ACTIVE HLQFP VFP 32 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR DRV591 DRV591VFPRG4 ACTIVE HLQFP VFP 32 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR DRV591 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 13-May-2014 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 18-Aug-2014 TAPE AND REEL INFORMATION *All dimensions are nominal Device DRV591VFPR Package Package Pins Type Drawing HLQFP VFP 32 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 1000 330.0 16.4 Pack Materials-Page 1 9.6 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 9.6 1.9 12.0 16.0 Q2 PACKAGE MATERIALS INFORMATION www.ti.com 18-Aug-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DRV591VFPR HLQFP VFP 32 1000 367.0 367.0 38.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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