LM5008SDX/NOPB

Order Now Product Folder Support & Community Tools & Software Technical Documents LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 LM5008 95-V, 350-mA, Constant On-Time DC/DC Buck Switching Regulator 1 Features 3 Description • • • • • • • The LM5008 350-mA step-down switching converter features all of the functions needed to implement a low-cost and efficient buck regulator. This highvoltage converter has an integrated 100-V N-channel buck switch and operates over an input voltage range of 9 V to 95 V. The device is easy to implement and is provided in the 8-pin VSSOP and the thermally enhanced 8-pin WSON packages. The converter uses a hysteretic control scheme with a PWM on-time inversely proportional to VIN. This feature allows the operating frequency to remain relatively constant. The hysteretic control requires no loop compensation. An intelligent current limit is implemented with forced offtime, which is inversely proportional to VOUT. This scheme ensures short-circuit protection while providing minimum foldback. Other protection features include: thermal shutdown, VCC undervoltage lockout, gate drive undervoltage lockout, and maximum duty cycle limiter. 1 • • • • • • • • Operating Input Voltage Range: 6 V to 95 V Integrated 100-V, N-Channel Buck Switch Internal VCC Regulator No Loop Compensation Required Ultra-Fast Transient Response On-Time Varies Inversely With Line Voltage Operating Frequency Remains Constant With Varying Line Voltage and Load Current Adjustable Output Voltage Highly Efficient Operation Precision Internal Reference Low Bias Current Intelligent Current Limit Protection Thermal Shutdown 8-Pin VSSOP and WSON Packages Create a Custom Design Using the LM5008 With the WEBENCH® Power Designer Device Information(1) PART NUMBER 2 Applications • • • PACKAGE LM5008 Non-Isolated Telecommunication Buck Regulators Secondary High-Voltage Post Regulators 48-V Automotive Systems BODY SIZE (NOM) VSSOP (8) 3.00 mm × 3.00 mm WSON (8) 4.00 mm × 4.00 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Typical Application Circuit and Block Diagram 7V SERIES REGULATOR 9.5 -95V Input LM5008 VCC 7 8 VIN C1 SD C5 C3 THERMAL SHUTDOWN UVLO ON TIMER START RON COMPLETE 6 SD / RON SHUTDOWN BST Ron OVER-VOLTAGE COMPARATOR + - 2.875V START UVLO 300 ns MIN OFF TIMER LEVEL SHIFT 3 RCL S REGULATION COMPARATOR FB 4 R SET L1 SW 1 VOUT1 Q Q CLR R1 COMPLETE RCL START CURRENT LIMIT OFF TIMER RCL C4 COMPLETE + FB VIN SD DRIVER 2.5V 5 2 + 0.50A BUCK SWITCH CURRENT SENSE R3 VOUT2 D1 RTN R2 C2 Copyright © 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 4 4 4 4 5 5 6 Absolute Maximum Ratings ...................................... ESD Ratings ............................................................ Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Switching Characteristics .......................................... Typical Characteristics .............................................. Detailed Description .............................................. 7 7.1 Overview ................................................................... 7 7.2 Functional Block Diagram ......................................... 7 7.3 Feature Description................................................... 8 7.4 Device Functional Modes ....................................... 11 8 Application and Implementation ........................ 12 8.1 Application Information............................................ 12 8.2 Typical Application .................................................. 12 9 Power Supply Recommendations...................... 16 10 Layout................................................................... 17 10.1 Layout Guidelines ................................................. 17 10.2 Layout Examples................................................... 17 11 Device and Documentation Support ................. 18 11.1 11.2 11.3 11.4 11.5 11.6 11.7 Device Support .................................................... Documentation Support ........................................ Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 18 18 19 19 19 19 19 12 Mechanical, Packaging, and Orderable Information ........................................................... 19 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision H (December 2016) to Revision I Page • Added links for WEBENCH ................................................................................................................................................... 1 • Changed VSSOP-8 body size to 3 mm × 3 mm in Device Information.................................................................................. 1 • Changed Layout Guidelines ................................................................................................................................................ 17 Changes from Revision G (March 2013) to Revision H Page • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .................................................................................................. 1 • Deleted Lead temperature, soldering (260°C maximum) ....................................................................................................... 4 • Changed RθJA values From: 200°C/W To: 139.7°C/W (VSSOP) and From: 40°C/W To: 42°C/W (WSON) .......................... 4 Changes from Revision F (March 2013) to Revision G • 2 Page Changed layout of National Semiconductor Data Sheet to TI format .................................................................................... 1 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 5 Pin Configuration and Functions DGK Package 8-Pin VSSOP Top View NGU Package 8-Pin WSON Top View SW 1 8 VIN BST 2 7 VCC RCL 3 6 RT/SD RTN 4 5 FB SW 1 BST 2 8 VIN 7 VCC EP RCL 3 6 RT/SD RTN 4 5 FB Not to scale Not to scale Pin Functions PIN NO. NAME TYPE DESCRIPTION 1 SW P Switching node: power switching node. Connect to the output inductor, re-circulating diode, and bootstrap capacitor. 2 BST I Boost pin (bootstrap capacitor input): an external capacitor is required between the BST and the SW pins. A 0.01-µF ceramic capacitor is recommended. An internal diode charges the capacitor from VCC. 3 RCL I Current limit OFF time set pin: a resistor between this pin and RTN sets the off-time when current limit is detected. The off-time is preset to 35 µs if FB = 0 V. Toff = 10–5 / (0.285 + (FB / 6.35 × 10−6 × RCL)) 4 RTN G Ground pin: ground for the entire circuit. 5 FB I Feedback input from regulated output: this pin is connected to the inverting input of the internal regulation comparator. The regulation threshold is 2.5 V. I On-time set pin: a resistor between this pin and VIN sets the switch on-time as a function of VIN. The minimum recommended on-time is 400 ns at the maximum input voltage. This pin can be used for remote shutdown. Ton = 1.25 × 10–10 RON / VIN 6 RON/SD 7 VCC P Output from the internal high voltage series pass regulator. Regulated at 7 V. If an auxiliary voltage is available to raise the voltage on this pin, above the regulation set point (7 V), the internal series pass regulator will shutdown, reducing the IC power dissipation. Do not exceed 14 V. This voltage provides gate drive power for the internal buck switch. An internal diode is provided between this pin and the BST pin. A local 0.1-µF decoupling capacitor is recommended. Series pass regulator is current limited to 10 mA. 8 VIN P Input voltage: recommended operating range is 9.5 V to 95 V. — EP G Exposed pad: the exposed pad has no electrical contact. Connect to system ground plane for reduced thermal resistance (WSON package only). Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 3 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN MAX UNIT VIN to GND –0.3 100 V BST to GND –0.3 114 V SW to GND (steady-state) –1 V BST to VCC 100 V BST to SW 14 V VCC to GND 14 V All other inputs to GND –0.3 7 V Storage temperature, Tstg –55 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) (2) (3) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) (2) UNIT ±2000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (3) V ±750 JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. The human body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN MAX VIN 9.5 95 UNIT V Operating junction temperature, TJ –40 125 °C 6.4 Thermal Information LM5008 THERMAL METRIC (1) DGK (VSSOP) NGU (WSON) 8 PINS 8 PINS UNIT RθJA Junction-to-ambient thermal resistance 139.7 42 °C/W RθJC(top) Junction-to-case (top) thermal resistance 51.2 27.6 °C/W RθJB Junction-to-board thermal resistance 70.5 18.5 °C/W ψJT Junction-to-top characterization parameter 3.4 0.3 °C/W ψJB Junction-to-board characterization parameter 69.5 18.5 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance — 4.3 °C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 6.5 Electrical Characteristics Specifications are for TJ = 25°C and VIN = 48 V (unless otherwise stated) (1). PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VCC SUPPLY VCC Reg TJ = 25°C VCC regulator output VCC current limit 7 TJ = –40°C to 125°C 6.6 (2) 7.4 9.5 VCC undervoltage lockout voltage VCC increasing VCC undervoltage hysteresis VCC UVLO delay (filter) 100-mV overdrive IIN operating current Non-switching, FB = 3 V IIN shutdown current RON/SD = 0 V TJ = 25°C mA 6.3 V 200 mV 10 µs 485 TJ = –40°C to 125°C 675 TJ = 25°C V 76 TJ = –40°C to 125°C 150 µA µA CURRENT LIMIT TJ = 25°C Current limit threshold 0.51 TJ = –40°C to 125°C 0.41 Current limit response time Iswitch overdrive = 0.1 A, time to switch off OFF time generator (test 1) FB = 0 V, RCL = 100 K OFF time generator (test 2) FB = 2.3 V, RCL = 100 K 0.61 A 400 ns 35 µs 2.56 µs ON-TIME GENERATOR TON – 1 VIN = 10 V, RON = 200 K TON – 2 VIN = 95 V, RON = 200 K Remote shutdown threshold Rising TJ = 25°C TJ = –40°C to 125°C 2.77 2.15 TJ = 25°C TJ = –40°C to 125°C 300 200 TJ = 25°C TJ = –40°C to 125°C 3.5 420 0.7 0.4 Remote shutdown hysteresis 1.05 µs ns V 35 mV 300 ns MINIMUM OFF-TIME Minimum off-timer FB = 0 V REGULATION AND OV COMPARATORS FB reference threshold Internal reference, trip point for switch ON FB overvoltage threshold Trip point for switch OFF TJ = 25°C TJ = –40°C to 125°C 2.5 2.445 FB bias current 2.55 V 2.875 V 100 nA 165 °C 25 °C THERMAL SHUTDOWN Tsd Thermal shutdown temperature Thermal shutdown hysteresis (1) (2) All electrical characteristics having room temperature limits are tested during production with TA = TJ = 25°C. All hot and cold limits are specified by correlating the electrical characteristics to process and temperature variations and applying statistical process control. The VCC output is intended as a self bias for the internal gate drive power and control circuits. Device thermal limitations limit external loading. 6.6 Switching Characteristics over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS Buck switch RDS(on) ITEST = 200 mA (1) Gate drive UVLO VBST – VSW rising TYP 2.47 TJ = 25°C TJ = –40°C to 125°C MAX 1.15 TJ = –40°C to 125°C Gate drive UVLO hysteresis (1) MIN TJ = 25°C 4.5 3.4 5.5 430 UNIT Ω V mV For devices procured in the 8-pin WSON package the RDS(on) limits are specified by design characterization data only. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 5 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 6.7 Typical Characteristics 2.0 8 RON = 500k 6 5 1.6 TON (Ps) ICC INPUT CURRENT (mA) 7 1.8 1.4 300k 4 3 2 100k 1.2 1 0 1.0 9 8 10 11 12 13 0 14 20 40 EXTERNALLY APPLIED VCC (V) 80 100 VIN (V) Figure 1. ICC Current vs Applied VCC Voltage Figure 2. On-Time vs Input Voltage and RON 700 35 48V 60V 80V 600 Max VIN = 30V 500 95V 400 300 200 100 CURRENT LIMIT OFF TIME (Ps) MAXIMUNM FREQUENCY (kHz) 60 30 25 20 15 RCL = 500k 300k 10 100k 5 50k 0 0 0 2.5 5.0 10 15 20 0 0.5 1.0 Figure 3. Maximum Frequency vs VOUT and VIN 2.5 Figure 4. Current Limit Off-Time vs VFB and RCL 10.2 100 VIN = 15V VOUT1 10.0 VIN = 48V 80 9.8 VOUT (V) EFFICIENCY (%) 2.0 VFB (V) VOUT (V) 90 1.5 VIN = 95V 70 VOUT2 9.6 60 9.4 50 9.2 40 100 9.0 VIN = 48V 200 300 LOAD CURRENT (mA) 100 200 300 LOAD CURRENT (mA) Figure 5. Efficiency vs Load Current vs VIN (Circuit of Figure 10) 6 0 Submit Documentation Feedback Figure 6. Output Voltage vs Load Current (Circuit of Figure 10) Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 7 Detailed Description 7.1 Overview The LM5008 regulator is an easy-to-use buck DC-DC converter that operates from 9.5-V to 95-V supply voltage. The device is intended for step-down conversions from 12-V, 24-V, and 48-V unregulated, semi-regulated and fully-regulated supply rails. With integrated buck power MOSFET, the LM5008 delivers up to 350-mA DC load current with exceptional efficiency and low input quiescent current in a very small solution size. Designed for simple implementation, a nearly fixed-frequency, constant on-time (COT) operation with discontinuous conduction mode (DCM) at light loads is ideal for low-noise, high current, fast transient load requirements. Control loop compensation is not required reducing design time and external component count. The LM5008 incorporates other features for comprehensive system requirements, including VCC undervoltage lockout (UVLO), gate drive undervoltage lockout, maximum duty cycle limiter, intelligent current limit off timer, a precharge switch, and thermal shutdown with automatic recovery. These features enable a flexible and easy-touse platform for a wide range of applications. The pin arrangement is designed for simple and optimized PCB layout, requiring only a few external components. 7.2 Functional Block Diagram 7V SERIES REGULATOR 9.5 -95V Input LM5008 VCC 7 8 VIN C1 SD C5 C3 THERMAL SHUTDOWN UVLO ON TIMER START RON COMPLETE 6 SD / RON SHUTDOWN BST Ron OVER-VOLTAGE COMPARATOR + - 2.875V START UVLO 300 ns MIN OFF TIMER LEVEL SHIFT RCL S REGULATION COMPARATOR FB 3 4 R SET L1 SW 1 VOUT1 Q Q CLR R1 COMPLETE RCL START CURRENT LIMIT OFF TIMER RCL C4 DRIVER + FB VIN SD COMPLETE 2.5V 5 2 + 0.50A BUCK SWITCH CURRENT SENSE R3 VOUT2 D1 RTN R2 C2 Copyright © 2016, Texas Instruments Incorporated Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 7 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 7.3 Feature Description 7.3.1 Hysteretic Control Circuit Overview The LM5008 is a buck DC-DC regulator that uses a control scheme in which the on-time varies inversely with line voltage (VIN). Control is based on a comparator and the on-time one-shot, with the output voltage feedback (FB) compared to an internal reference (2.5 V). If the FB level is below the reference the buck switch is turned on for a fixed time determined by the line voltage and a programming resistor (RON). Following the ON period, the switch remains off for at least the minimum off-timer period of 300 ns. If FB is still below the reference at that time, the switch turns on again for another on-time period. This will continue until regulation is achieved. The LM5008 operates in discontinuous conduction mode at light load currents, and continuous conduction mode at heavy load current. In discontinuous conduction mode, current through the output inductor starts at zero and ramps up to a peak during the on-time, then ramps back to zero before the end of the off-time. The next on-time period starts when the voltage at FB falls below the internal reference; until then, the inductor current remains zero. In this mode the operating frequency is lower than in continuous conduction mode, and varies with load current. Therefore at light loads the conversion efficiency is maintained, because the switching losses reduce with the reduction in load and frequency. The discontinuous operating frequency can be calculated with Equation 1. VOUT2 x L x 1.28 x 1020 F= RL x (RON)2 where • RL = the load resistance (1) In continuous conduction mode, current flows continuously through the inductor and never ramps down to zero. In this mode the operating frequency is greater than the discontinuous mode frequency and remains relatively constant with load and line variations. The approximate continuous mode operating frequency can be calculated with Equation 2. VOUT F= 1.25 x 10-10 x RON (2) The output voltage (VOUT) can be programmed by two external resistors as shown in Functional Block Diagram. The regulation point can be calculated with Equation 3. VOUT = 2.5 × (R1 + R2) / R2 (3) All hysteretic regulators regulate the output voltage based on ripple voltage at the feedback input, requiring a minimum amount of ESR for the output capacitor C2. A minimum of 25 mV to 50 mV of ripple voltage at the feedback pin (FB) is required for the LM5008. In cases where the capacitor ESR is too small, additional series resistance may be required (R3 in Functional Block Diagram). For applications where lower output voltage ripple is required the output can be taken directly from a low-ESR output capacitor, as shown in Figure 7. However, R3 slightly degrades the load regulation. L1 SW LM5008 R1 R3 FB VOUT2 R2 C2 Copyright © 2016, Texas Instruments Incorporated Figure 7. Low-Ripple Output Configuration 8 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 Feature Description (continued) 7.3.2 High Voltage Start-Up Regulator The LM5008 contains an internal high voltage start-up regulator. The input pin (VIN) can be connected directly to the line voltages up to 95 Volts, with transient capability to 100 V. The regulator is internally current limited to 9.5 mA at VCC. Upon power up, the regulator sources current into the external capacitor at VCC (C3). When the voltage on the VCC pin reaches the undervoltage lockout threshold of 6.3 V, the buck switch is enabled. In applications involving a high value for VIN, where power dissipation in the VCC regulator is a concern, an auxiliary voltage can be diode connected to the VCC pin. Setting the auxiliary voltage to 8 V to 14 V shuts off the internal regulator, reducing internal power dissipation. See Figure 8. The current required into the VCC pin is shown in Figure 1. VCC C3 BST C4 LM5008 L1 D2 SW D1 R1 R3 FB VOUT2 R2 C2 Copyright © 2016, Texas Instruments Incorporated Figure 8. Self-Biased Configuration 7.3.3 Regulation Comparator The feedback voltage at FB is compared to an internal 2.5-V reference. In normal operation (the output voltage is regulated), an on-time period is initiated when the voltage at FB falls below 2.5 V. The buck switch stays on for the on-time, causing the FB voltage to rise above 2.5 V. After the on-time period, the buck switch stays off until the FB voltage again falls below 2.5 V. During start-up, the FB voltage is below 2.5 V at the end of each on-time, resulting in the minimum off-time of 300 ns. Bias current at the FB pin is nominally 100 nA. 7.3.4 Overvoltage Comparator The feedback voltage at FB is compared to an internal 2.875-V reference. If the voltage at FB rises above 2.875 V, the on-time pulse is immediately terminated. This condition can occur if the input voltage, or the output load, change suddenly. The buck switch will not turn on again until the voltage at FB falls below 2.5 V. 7.3.5 On-Time Generator and Shutdown The on-time for the LM5008 is determined by the RON resistor, and is inversely proportional to the input voltage (VIN), resulting in a nearly constant frequency as VIN is varied over its range. Equation 4 shows the on-time equation for the LM5008. TON = 1.25 × 10–10 × RON / VIN (4) See Figure 2. RON should be selected for a minimum on-time (at maximum VIN) greater than 400 ns for proper current limit operation. This requirement limits the maximum frequency for each application, depending on VIN and VOUT. See Figure 3. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 9 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com Feature Description (continued) The LM5008 can be remotely disabled by taking the RON/SD pin to ground. See Figure 9. The voltage at the RON/SD pin is between 1.5 and 3 volts, depending on VIN and the value of the RON resistor. Input Voltage VIN RON LM5008 RON/SD STOP RUN Copyright © 2016, Texas Instruments Incorporated Figure 9. Shutdown Implementation 7.3.6 Current Limit The LM5008 contains an intelligent current limit off-timer. If the current in the buck switch exceeds 0.5 A the present cycle is immediately terminated, and a non-resetable off-timer is initiated. The length of off-time is controlled by an external resistor (RCL) and the FB voltage (see Figure 4). When FB = 0 V, a maximum off-time is required, and the time is preset to 35 µs. This condition occurs when the output is shorted, and during the initial part of start-up. This amount of time ensures safe short-circuit operation up to the maximum input voltage of 95 V. In cases of overload where the FB voltage is above zero volts (not a short circuit), the current limit off-time will be less than 35 µs. Reducing the off-time during less severe overloads reduces the amount of foldback, recovery time, and the start-up time. The off-time is calculated from Equation 5. 10 TOFF = -5 VFB 0.285 + -6 (6.35 x 10 x RCL) (5) The current limit sensing circuit is blanked for the first 50-70 ns of each on-time so it is not falsely tripped by the current surge which occurs at turnon. The current surge is required by the re-circulating diode (D1) for its turnoff recovery. 7.3.7 N-Channel Buck Switch and Driver The LM5008 integrates an N-Channel Buck switch and associated floating high voltage gate driver. The gate driver circuit works in conjunction with an external bootstrap capacitor and an internal high voltage diode. A 0.01µF ceramic capacitor (C4) connected between the BST pin and SW pin provides the voltage to the driver during the on-time. During each off-time, the SW pin is at approximately 0 V, and the bootstrap capacitor charges from VCC through the internal diode. The minimum off-timer, set to 300 ns, ensures a minimum time each cycle to recharge the bootstrap capacitor. An external re-circulating diode (D1) carries the inductor current after the internal Buck switch turns off. This diode must be of the ultra-fast or Schottky type to minimize turnon losses and current overshoot. 7.3.8 Thermal Protection The LM5008 must be operated so the junction temperature does not exceed 125°C during normal operation. An internal thermal shutdown circuit is provided to protect the LM5008 in the event of a higher than normal junction temperature. When activated, typically at 165°C, the controller is forced into a low power reset state, disabling the buck switch and the VCC regulator. This feature prevents catastrophic failures from accidental device overheating. When the junction temperature reduces below 140°C (typical hysteresis = 25°C), the VCC regulator is enabled, and normal operation is resumed. 10 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 7.4 Device Functional Modes 7.4.1 Shutdown Mode The RON/SD pin provides ON and OFF control for the LM5008. When VSD is below approximately 0.7 V, the device is in shutdown mode. Both the internal LDO and the switching regulator are off. The quiescent current in shutdown mode drops to 76 µA (typical) at VIN = 48 V. The LM5008 also employs VCC bias rail undervoltage protection. If the VCC bias supply voltage is below its UV threshold, the regulator remains off. 7.4.2 Active Mode LM5008 is in active mode when the internal bias rail, VCC, is above its UV threshold. Depending on the load current, the device operates in either DCM or CCM mode. Whenever the load current is reduced to a level less than half the peak-to-peak inductor ripple current, the device enters discontinuous conduction mode (DCM). Calculate the critical conduction boundary using Equation 6. IBOUNDARY 'IL 2 VOUT ˜ 1 D 2 ˜ LF ˜ FSW (6) When the inductor current reaches zero, the SW node becomes high impedance. Resonant ringing occurs at SW as a result of the LC tank circuit formed by the buck inductor and the parasitic capacitance at the SW node. At light loads, several pulses may be skipped in between switching cycles, effectively reducing the switching frequency and further improving light-load efficiency. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 11 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The final circuit is shown in Figure 10. The circuit was tested, and the resulting performance is shown in Figure 12 through Figure 6. 8.1.1 Minimum Load Current A minimum load current of 1 mA is required to maintain proper operation. If the load current falls below that level, the bootstrap capacitor may discharge during the long off-time, and the circuit will either shutdown or cycle on and off at a low frequency. If the load current is expected to drop below 1 mA in the application, the feedback resistors should be chosen low enough in value so they provide the minimum required current at nominal VOUT. 8.2 Typical Application 12 - 95V Input VCC VIN 7 8 C1 1.0 µF C3 0.1 µF C5 0.1 µF BST RON 357k 2 RON / SD 6 LM5008 C4 0.01 µF L1 220 µH 10.0V SW VOUT1 1 SHUTDOWN D1 RCL R1 R3 3.01k 2.0 3 RCL 267k RTN VOUT2 FB R2 5 1.0k 4 C2 15 µF GND Copyright © 2016, Texas Instruments Incorporated Figure 10. LM5008 Example Circuit 8.2.1 Design Requirements A guide for determining the component values will be illustrated with a design example. Table 1 lists the bill of materials for this application. The following steps will configure the LM5008 for: • Input voltage range (VIN): 12 V to 95 V • Output voltage (VOUT1): 10 V • Load current (for continuous conduction mode): 100 mA to 300 mA • Maximum ripple at VOUT2: 100 mVp-p at maximum input voltage 12 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 Typical Application (continued) Table 1. Bill of Materials (Circuit of Figure 10) ITEM DESCRIPTION PART NUMBER VALUE C1 Ceramic Capacitor TDK C4532X7R2A105M 1 µF, 100 V C2 Ceramic Capacitor TDK C4532X7R1E156M 15 µF, 25 V C3 Ceramic Capacitor Kemet C1206C104K5RAC 0.1 µF, 50 V C4 Ceramic Capacitor Kemet C1206C103K5RAC 0.01 µF, 50 V C5 Ceramic Capacitor TDK C3216X7R2A104M 0.1 µF, 100 V D1 Ultra-Fast Power Diode ON Semi MURA110T3 100 V, 1 A L1 Power Inductor Coilcraft DO3316-224 or 220 µH TDK SLF10145T-221MR65 R1 Resistor Vishay CRCW12063011F 3.01 kΩ R2 Resistor Vishay CRCW12061001F 1 kΩ R3 Resistor Vishay CRCW12062R00F 2Ω RON Resistor Vishay CRCW12063573F 357 kΩ RCL Resistor Vishay CRCW12062673F 267 kΩ U1 Switching Regulator Texas Instruments LM5008 8.2.2 Detailed Design Procedure 8.2.2.1 Custom Design With WEBENCH® Tools Click here to create a custom design using the LM5008 device with the WEBENCH® Power Designer. 1. Start by entering the input voltage (VIN), output voltage (VOUT), and output current (IOUT) requirements. 2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial. 3. Compare the generated design with other possible solutions from Texas Instruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricing and component availability. In most cases, these actions are available: • Run electrical simulations to see important waveforms and circuit performance • Run thermal simulations to understand board thermal performance • Export customized schematic and layout into popular CAD formats • Print PDF reports for the design, and share the design with colleagues Get more information about WEBENCH tools at www.ti.com/WEBENCH. R1 and R2: From Functional Block Diagram, VOUT1 = VFB × (R1 + R2) / R2, and because VFB = 2.5 V, the ratio of R1 to R2 calculates as 3:1. Standard values of 3.01 kΩ (R1) and 1.00 kΩ (R2) are chosen. Other values could be used as long as the 3:1 ratio is maintained. The selected values, however, provide a small amount of output loading (2.5 mA) in the event the main load is disconnected. This allows the circuit to maintain regulation until the main load is reconnected. Fs and RON: The recommended operating frequency range for the LM5008 is 50 kHz to 600 kHz. Unless the application requires a specific frequency, the choice of frequency is generally a compromise because it affects the size of L1 and C2, and the switching losses. The maximum allowed frequency, based on a minimum on-time of 400 ns, is calculated from Equation 7: FMAX = VOUT / (VINMAX × 400 ns) (7) For this exercise, FMAX = 263 kHz. From Equation 2, RON calculates to 304 kΩ. A standard value 357-kΩ resistor is used to allow for tolerances in Equation 2, resulting in a frequency of 224 kHz. L1: The main parameter affected by the inductor is the output current ripple amplitude. The choice of inductor value therefore depends on both the minimum and maximum load currents, keeping in mind that the maximum ripple current occurs at maximum VIN. a. Minimum load current: To maintain continuous conduction at minimum Io (100 mA), the ripple amplitude Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 13 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com (IOR) must be less than 200 mAp-p so the lower peak of the waveform does not reach zero. L1 is calculated using Equation 8. VOUT1 x (VIN - VOUT1) L1 = IOR x Fs x VIN (8) At VIN = 95 V, L1 (minimum) calculates to 200 µH. The next larger standard value (220 µH) is chosen and with this value IOR calculates to 181 mAp-p at VIN = 95 V, and 34 mAp-p at VIN = 12 V. b. Maximum load current: At a load current of 300 mA, the peak of the ripple waveform must not reach the minimum value of the LM5008’s current limit threshold (410 mA). Therefore the ripple amplitude must be less than 220 mAp-p, which is already satisfied in Equation 8. With L1 = 220 µH, at maximum VIN and IO, the peak of the ripple will be 391 mA. While L1 must carry this peak current without saturating or exceeding its temperature rating, it also must be capable of carrying the maximum value of the LM5008’s current limit threshold (610 mA) without saturating, because the current limit is reached during start-up. The DC resistance of the inductor should be as low as possible. For example, if the inductor’s DCR is 1 Ω, the power dissipated at maximum load current is 0.09 W. While small, it is not insignificant compared to the load power of 3 W. C3: The capacitor on the VCC output provides not only noise filtering and stability, but its primary purpose is to prevent false triggering of the VCC UVLO at the buck switch ON/OFF transitions. For this reason, C3 should be no smaller than 0.1 µF. C2, and R3: When selecting the output filter capacitor C2, the items to consider are ripple voltage due to its ESR, ripple voltage due to its capacitance, and the nature of the load. a. ESR and R3: A low ESR for C2 is generally desirable so as to minimize power losses and heating within the capacitor. However, a hysteretic regulator requires a minimum amount of ripple voltage at the feedback input for proper loop operation. For the LM5008 the minimum ripple required at pin 5 is 25 mVp-p, requiring a minimum ripple at VOUT1 of 100 mV. Because the minimum ripple current (at minimum VIN) is 34 mAp-p, the minimum ESR required at VOUT1 is 100 mV / 34 mA = 2.94 Ω. Because quality capacitors for SMPS applications have an ESR considerably less than this, R3 is inserted as shown in Functional Block Diagram. R3’s value, along with C2’s ESR, must result in at least 25 mVp-p ripple at pin 5. Generally, R3 will be 0.5 to 3 Ω. b. Nature of the Load: The load can be connected to VOUT1 or VOUT2. VOUT1 provides good regulation, but with a ripple voltage which ranges from 100 mV (at VIN = 12 V) to 500 mV (at VIN = 95 V). Alternatively, VOUT2 provides low ripple, but lower regulation due to R3. For a maximum allowed ripple voltage of 100 mVp-p at VOUT2 (at VIN = 95 V), assume an ESR of 0.4 Ω for C2. At maximum VIN, the ripple current is 181 mAp-p, creating a ripple voltage of 72 mVp-p. This leaves 28 mVp-p of ripple due to the capacitance. The average current into C2 due to the ripple current is calculated using the waveform in Figure 11. L1 Current 391 mA 300 mA 209 mA 0 mA 1/Freq. = Ts Ts/2 Figure 11. Inductor Current Waveform Starting when the current reaches Io (300 mA in Figure 11) half way through the on-time, the current continues to increase to the peak (391 mA), and then decreases to 300 mA half way through the off-time. The average value of this portion of the waveform is 45.5 mA, and will cause half of the voltage ripple, or 14 mV. The interval is one half of the frequency cycle time, or 2.23 µs. Using the capacitor’s basic equation (see Equation 9), the minimum value for C2 is 7.2 µF. 14 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 The ripple due to C2’s capacitance is 90° out of phase from the ESR ripple, and the two numbers do not add directly. However, this calculation provides a practical minimum value for C2 based on its ESR and the target spec. To allow for the capacitor’s tolerance, temperature effects, and voltage effects, a 15-µF, X7R capacitor is used. c. In summary: The above calculations provide a minimum value for C2 and a calculation for R3. The ESR is just as important as the capacitance. The calculated values are guidelines, and should be treated as starting points. For each application, experimentation is needed to determine the optimum values for R3 and C2. C = I × Δt / ΔV (9) RCL: When a current limit condition is detected, the minimum off-time set by this resistor must be greater than the maximum normal off-time which occurs at maximum VIN. Using Equation 4, the minimum on-time is 0.47 µs, yielding a maximum off-time of 3.99 µs. This is increased by 117 ns (to 4.11 µs) due to a ±25% tolerance of the on-time. This value is then increased to allow for: The response time of the current limit detection loop (400 ns). The off-time determined by Equation 5 has a ±25% tolerance. tOFFCL(MIN) = (4.11 µs + 0.40 µs) × 1.25 = 5.64 µs (10) Using Equation 5, RCL calculates to 264 kΩ (at VFB = 2.5 V). The closest standard value is 267 kΩ. D1: The important parameters are reverse recovery time and forward voltage. The reverse recovery time determines how long the reverse current surge lasts each time the buck switch is turned on. The forward voltage drop is significant in the event the output is short-circuited as it is only this diode’s voltage which forces the inductor current to reduce during the forced off-time. For this reason, a higher voltage is better, although that affects efficiency. A good choice is an ultra-fast power diode, such as the MURA110T3 from ON Semiconductor. Its reverse recovery time is 30 ns, and its forward voltage drop is approximately 0.72 V at 300 mA at 25°C. Other types of diodes may have a lower forward voltage drop, but may have longer recovery times, or greater reverse leakage. D1’s reverse voltage rating must be at least as great as the maximum VIN, and its current rating be greater than the maximum current limit threshold (610 mA). C1: This capacitor’s purpose is to supply most of the switch current during the on-time, and limit the voltage ripple at VIN, on the assumption that the voltage source feeding VIN has an output impedance greater than zero. At maximum load current when the buck switch turns on, the current into pin 8 will suddenly increase to the lower peak of the output current waveform, ramp up to the peak value, then drop to zero at turnoff. The average input current during this on-time is the load current (300 mA). For a worst case calculation, C1 must supply this average load current during the maximum on-time. To keep the input voltage ripple to less than 2 V (for this exercise), C1 is calculated with Equation 11. C1 = I x tON 'V = 0.3A x 3.72 Ps = 0.56 PF 2.0V (11) Quality ceramic capacitors in this value have a low ESR which adds only a few millivolts to the ripple. It is the capacitance which is dominant in this case. To allow for the capacitor’s tolerance, temperature effects, and voltage effects, a 1.0-µF, 100-V, X7R capacitor will be used. C4: The recommended value is 0.01 µF for C4, as this is appropriate in the majority of applications. A highquality ceramic capacitor, with low ESR is recommended as C4 supplies the surge current to charge the buck switch gate at turnon. A low ESR also ensures a quick recharge during each off-time. At minimum VIN, when the on-time is at maximum, it is possible during start-up that C4 will not fully recharge during each 300-ns off-time. The circuit will not be able to complete the start-up, and achieve output regulation. This can occur when the frequency is intended to be low (for example, RON = 500 K). In this case C4 should be increased so it can maintain sufficient voltage across the buck switch driver during each on-time. C5: This capacitor helps avoid supply voltage transients and ringing due to long lead inductance at VIN. A lowESR, 0.1-µF ceramic chip capacitor is recommended, placed close to the LM5008. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 15 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 8.2.3 Application Curves 100 100 90 90 80 80 EFFICIENCY (%) EFFICIENCY (%) VIN = 15V 70 60 VIN = 95V 70 60 IOUT = 300 mA 50 50 40 100 40 0 20 40 VIN = 48V 60 80 100 VIN (V) 200 300 LOAD CURRENT (mA) Figure 12. Efficiency vs VIN Figure 13. Efficiency vs Load Current vs VIN 9 Power Supply Recommendations The LM5008 converter is designed to operate from a wide input voltage range from 9.5 V to 95 V. The characteristics of the input supply must be compatible with the Absolute Maximum Ratings and Recommended Operating Conditions. In addition, the input supply must be capable of delivering the required input current to the fully-loaded regulator. Estimate the average input current with Equation 12. VOUT ˜ IOUT VIN ˜ K IIN where • η is the efficiency (12) If the converter is connected to an input supply through long wires or PCB traces with large impedance, sachieving stable performance requires special care. The parasitic inductance and resistance of the input cables may have an adverse affect on converter operation. The parasitic inductance in combination with the low-ESR ceramic input capacitors form an underdamped resonant circuit. This circuit can cause overvoltage transients at VIN each time the input supply is cycled ON and OFF. The parasitic resistance causes the input voltage to dip during a load transient. If the regulator is operating close to the minimum input voltage, this dip can cause false UVLO fault triggering and a system reset. The best way to solve such issues is to reduce the distance from the input supply to the regulator and use an aluminum or tantalum input capacitor in parallel with the ceramics. The moderate ESR of the electrolytic capacitors helps to damp the input resonant circuit and reduce any voltage overshoots. A capacitance in the range of 10 µF to 47 µF is usually sufficient to provide input damping and helps to hold the input voltage steady during large load transients. An EMI input filter is often used in front of the regulator that, unless carefully designed, can lead to instability as well as some of the effects mentioned above. The user's guide Simple Success with Conducted EMI for DC-DC Converters (SNVA489) provides helpful suggestions when designing an input filter for any switching regulator. 16 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 10 Layout 10.1 Layout Guidelines The LM5008 regulation and overvoltage comparators are very fast, and as such responds to short-duration noise pulses. Layout considerations are therefore critical for optimum performance: 1. Minimize the area of the high di/dt switching current loop consisting of the VIN pin, input ceramic capacitor, SW node and freewheeling power diode. Keep the input capacitor as close as possible to the VIN pin and route a short, direct connection to the RTN pin using polygon copper pours. 2. Minimize SW copper area to reduce radiated noise related to high dv/dt. 3. Locate all components as physically close as possible to their respective pins, thereby minimizing noise pickup in the printed-circuit tracks. 4. Locate the FB trace away from noise sources and inductors. Place the resistor close to the FB pin to minimize the length of the FB trace. If the internal dissipation of the LM5008 converter produces excessive junction temperatures during normal operation, optimal use of the PCB ground plane can help considerably to dissipate heat. The exposed pad on the bottom of the WSON-8 package can be soldered to a ground plane on the PCB, and that plane should extend out from beneath the IC to help dissipate the heat. Additionally, the use of wide PCB traces for power connection can also help conduct heat away from the IC. Judicious positioning of the LM5008 converter within the end product, along with use of any available air flow (forced or natural convection), can help reduce the operating junction temperature. 10.2 Layout Examples VOUT CA COUT GND L1 CIN RA D1 CBST SW VIN SW VCC BST VIN CVCC LM5008 RT/SD RTN FB RT RCL RCL RFB1 Via to VIN RFB2 CB Via to Ground Plane Figure 14. LM5008 Evaluation Board Top Layer Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 17 LM5008 SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 www.ti.com 11 Device and Documentation Support 11.1 Device Support 11.1.1 Third-Party Products Disclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE. 11.1.2 Custom Design With WEBENCH® Tools Click here to create a custom design using the LM5008 device with the WEBENCH® Power Designer. 1. Start by entering the input voltage (VIN), output voltage (VOUT), and output current (IOUT) requirements. 2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial. 3. Compare the generated design with other possible solutions from Texas Instruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricing and component availability. In most cases, these actions are available: • Run electrical simulations to see important waveforms and circuit performance • Run thermal simulations to understand board thermal performance • Export customized schematic and layout into popular CAD formats • Print PDF reports for the design, and share the design with colleagues Get more information about WEBENCH tools at www.ti.com/WEBENCH. 11.1.3 Development Support For development support see the following: • For TI's reference design library, visit TI Designs • For TI's WEBENCH Design Environments, visit WEBENCH® Design Center 11.2 Documentation Support 11.2.1 Related Documentation For related documentation see the following: • LM5008 Quick-start Calculator • AN-1330 LM5008 Evaluation Board (SNVA380) • AN-1925 LM5008A Evaluation Board (SNVA380) • Buck Regulator Topologies for Wide Input/Output Voltage Differentials (SNVA594) 11.2.1.1 PCB Layout Resources • AN-1149 Layout Guidelines for Switching Power Supplies (SNVA021) • AN-1229 Simple Switcher PCB Layout Guidelines (SNVA054) • Constructing Your Power Supply – Layout Considerations (SLUP230) • Low Radiated EMI Layout Made SIMPLE with LM4360x and LM4600x (SNVA721) • AN-2162 Simple Success With Conducted EMI From DC-DC Converters (SNVA489) • Reduce Buck-Converter EMI and Voltage Stress by Minimizing Inductive Parasitics (SLYT682) • White Papers: – Valuing Wide VIN, Low EMI Synchronous Buck Circuits for Cost-driven, Demanding Applications – An Overview of Conducted EMI Specifications for Power Supplies – An Overview of Radiated EMI Specifications for Power Supplies 18 Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 LM5008 www.ti.com SNVS280I – APRIL 2004 – REVISED OCTOBER 2018 Documentation Support (continued) 11.2.1.2 Thermal Design Resources • AN-2020 Thermal Design By Insight, Not Hindsight (SNVA419) • AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Pad Packages (SNVA183) • Semiconductor and IC Package Thermal Metrics (SPRA953) • Thermal Design Made Simple with LM43603 and LM43602 (SNVA719) • PowerPAD™Thermally Enhanced Package (SLMA002) • PowerPAD Made Easy (SLMA004) • Using New Thermal Metrics (SBVA025) • Power House Blogs: – High-Density PCB Layout of DC/DC Converters 11.3 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.4 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.5 Trademarks PowerPAD, E2E are trademarks of Texas Instruments. WEBENCH is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.6 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.7 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Documentation Feedback Copyright © 2004–2018, Texas Instruments Incorporated Product Folder Links: LM5008 19 PACKAGE OPTION ADDENDUM www.ti.com 30-Sep-2021 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) LM5008MM NRND VSSOP DGK 8 1000 Non-RoHS & Green Call TI Level-1-260C-UNLIM -40 to 125 SAYB LM5008MM/NOPB ACTIVE VSSOP DGK 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 SAYB LM5008MMX NRND VSSOP DGK 8 3500 Non-RoHS & Green Call TI Level-1-260C-UNLIM -40 to 125 SAYB LM5008MMX/NOPB ACTIVE VSSOP DGK 8 3500 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 SAYB LM5008SD NRND WSON NGU 8 1000 Non-RoHS & Green Call TI Level-1-260C-UNLIM LM5008SDC/NOPB ACTIVE WSON NGU 8 1000 RoHS & Green NIPDAU | SN Level-1-260C-UNLIM -40 to 125 L5008SD LM5008SDCX/NOPB ACTIVE WSON NGU 8 4500 RoHS & Green NIPDAU | SN Level-1-260C-UNLIM -40 to 125 L5008SD L00040B (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of