Power Management

LM25011Q1MY/NOPB.A

Texas Instruments

LM25011, LM25011-Q1, LM25011A, LM25011A-Q1 42-V 2-A Constant On-Time Switching Regulator With Adjustable Current Limit REVISED NOVEMBER 2014

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Tools & Software Support & Community 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. LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 LM25011,LM25011-Q1,LM25011A,LM25011A-Q142-V2-AConstantOn-TimeSwitching RegulatorWithAdjustableCurrentLimit

1 Features

1• LM25011-Q1 is an Automotive Grade Product that is AEC-Q100 Grade 1 Qualified (–40°C to +125°C Operating Junction Temperature)

LM25011A Allows Low-Dropout Operation at High Switching Frequency
Input Operating Voltage Range: 6 V to 42 V
Absolute Maximum Input Rating: 45 V
Integrated 2-A N-Channel Buck Switch
Adjustable Current Limit Allows for Smaller Inductor
Adjustable Output Voltage from 2.51 V
Minimum Ripple Voltage at VOUT
Power Good Output
Switching Frequency Adjustable to 2 MHz
COT Topology Features: – Switching Frequency Remains Nearly Constant with Load Current and Input Voltage Variations – Ultra-Fast Transient Response – No Loop Compensation Required – Stable Operation with Ceramic Output Capacitors – Allows for Smaller Output Capacitor and Current Sense Resistor
Adjustable Soft-Start Timing
Thermal Shutdown
Precision 2% Feedback Reference
Package: 10-Pin, HVSSOP
Create a Custom Design Using the LM25011 Family with the WEBENCH Power Designer

2 Applications

Automotive Safety
Infotainment
Telecommunication
Front Camera

3 Description

The LM25011 constant on-time step-down switching regulator features all the functions needed to implement a low-cost, efficient, buck bias regulator capable of supplying up to 2 A of load current. This high-voltage regulator contains an N-Channel Buck switch, a startup regulator, current limit detection, and internal ripple control. The constant on-time regulation principle requires no loop compensation, results in fast load transient response, and simplifies circuit implementation. The operating frequency remains constant with line and load. The adjustable valley current limit detection results in a smooth transition from constant voltage to constant current mode when current limit is reached, without the use of current limit foldback. The PGD output indicates the output voltage has increased to within 5% of the expected regulation value. Additional features include: Low output ripple, VIN under-voltage lock- out, adjustable soft-start timing, thermal shutdown, gate drive pre-charge, gate drive under-voltage lock- out, and maximum duty cycle limit. The LM25011A has a shorter minimum off-time than the LM25011, which allows for higher frequency operation at low input voltages. Device Information(1) PART NUMBER PACKAGE BODY SIZE (NOM) LM25011 / -Q1 HVSSOP (10) 3.00 mm × 3.00 mm LM25011A / -Q1 (1) For all available packages, see the orderable addendum at the end of the data sheet. Typical Application

11.2 Receiving Notification of Documentation Updates 24

12 Mechanical, Packaging, and Orderable

4 Revision History

NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision G (February 2013) to Revision H Page

Added Pin Configuration and Functions section, Handling Rating 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 Changes from Revision F (February 2013) to Revision G Page

5 Pin Configuration and Functions

PIN I/O DESCRIPTION APPLICATION INFORMATION NUMBER NAME 1 VIN I Input supply voltage Operating input range is 6 V to 42 V. Transient capability is 45 V. A low ESR capacitor must be placed as close as possible to the VIN and SGND pins.

2 RT I On-time Control An external resistor from VIN to this pin sets the buck switch on-

time and the switching frequency.

3 PGD – Power Good Logic output indicates when the voltage at the FB pin has

increased to above 95% of the internal reference voltage. Hysteresis is provided. An external pull-up resistor to a voltage less than 7 V is required.

4 SS I Soft-Start An internal current source charges an external capacitor to

provide the soft-start function.

5 SGND Signal Ground Ground for all internal circuitry other than the current limit sense

circuit. 6 FB I Feedback Internally connected to the regulation comparator. The regulation level is 2.51 V. 7 CSG – Current Sense Ground Ground connection for the current limit sensing circuit. Connect to ground and to the current sense resistor.

8 CS I Current sense Connect to the current sense resistor and the anode of the free-

wheeling diode. 9 SW O Switching Node Internally connected to the buck switch source. Connect to the external inductor, cathode of the free-wheeling diode, and bootstrap capacitor.

10 BST I Bootstrap capacitor connection of

the buck switch gate driver. Connect a 0.1-µF capacitor from SW to this pin. The capacitor is charged during the buck switch off-time via an internal diode. - EP – Exposed Pad Exposed pad on the underside of the package. This pad should be soldered to the PC board ground plane to aid in heat dissipation.

LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 www.ti.com Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation Feedback Copyright © 2009–2014, Texas Instruments Incorporated (1) Absolute Maximum Ratings(1) are limits beyond which damage to the device may occur. Recommended Operating Conditions are conditions under which operation of the device is intended to be functional. For specifications and test conditions, see the Electrical Characteristics .

6 Specifications

6.1 Absolute Maximum Ratings(1)

VIN to SGND (TJ = 25°C) 45 V BST to SGND 52 V SW to SGND (Steady State) –1.5 45 V BST to SW –0.3 7 V CS to CSG –0.3 0.3 V CSG to SGND –0.3 0.3 V PGD to SGND –0.3 7 V SS to SGND –0.3 3 V RT to SGND –0.3 1 V FB to SGND –0.3 7 V For soldering specs, see www.ti.com/packaging. Junction Temperature 150 °C (1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. (2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.2 Handling Ratings: LM25011

Tstg Storage temperature range –65 150 °C V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(1) 2000 V Charged device model (CDM), per JEDEC specification JESD22-C101, all pins(2) 750 (1) AEC Q100-002 indicates HBM stressing is done in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.3 Handling Ratings: LM25011-Q1

Tstg Storage temperature range –65 150 °C V(ESD) Electrostatic discharge Human body model (HBM), per AEC Q100-002(1) 2000 VCharged device model (CDM), per AEC Q100-011 Corner pins (1, 5, 6, and 10) 750 Other pins 750 (1) Absolute Maximum Ratings(1) are limits beyond which damage to the device may occur. Recommended Operating Conditions are conditions under which operation of the device is intended to be functional. For specifications and test conditions, see the Electrical Characteristics .

6.4 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)(1) MIN MAX UNIT VIN Voltage 6.0 42 V Junction Temperature –40 125 °C

LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 www.ti.com SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation FeedbackCopyright © 2009–2014, Texas Instruments Incorporated (1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Thermal Information

THERMAL METRIC(1) HVSSOP (DGQ) UNIT

10 PINS

RθJA Junction-to-ambient thermal resistance 48 °C/W RθJC(top) Junction-to-case (top) thermal resistance 54.3 RθJB Junction-to-board thermal resistance 34.2 ψJT Junction-to-top characterization parameter 4.0 ψJB Junction-to-board characterization parameter 33.9 RθJC(bot) Junction-to-case (bottom) thermal resistance 10

LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 www.ti.com Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation Feedback Copyright © 2009–2014, Texas Instruments Incorporated (1) Current flow out of a pin is indicated as a negative number. (2) All hot and cold limits are specified by correlating the electrical characteristics to process and temperature variations and applying statistical process control. (3) The junction temperature (TJ in °C) is calculated from the ambient temperature (TA in °C) and power dissipation (PD in watts) as follows: TJ = TA + (PD × RθJA ) where RθJA (in °C/W) is the package thermal impedance provided in the Thermal Information section.

6.6 Electrical Characteristics

Typical values correspond to TJ = 25°C. Minimum and maximum limits apply over –40°C to 125°C junction temperature range unless otherwise stated. Unless otherwise stated, the following conditions apply: VIN = 12 V, RT = 50 kΩ.(1) (2) (3) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT INPUT (VIN PIN) IIN Input operating current Non-switching, FB = 3 V 1200 1600 µA UVLOVIN VIN undervoltage lock-out threshold VIN increasing 4.6 5.3 5.9 V VIN undervoltage lock-out threshold hysteresis 200 mV SWITCH CHARACTERISTICS RDS(ON) Buck Switch RDS(ON) ITEST = 200 mA 0.3 0.6 Ω UVLOGD Gate Drive UVLO BST-SW 2.4 3.4 4.4 V UVLOGD Hysteresis 350 mV Pre-charge switch voltage ITEST = 10 mA into SW pin 1.4 V Pre-charge switch on-time 120 ns SOFT-START PIN VSS Pullup voltage 2.51 V ISS Internal current source 10 µA VSS-SH Shutdown threshold 70 140 mV CURRENT LIMIT VILIM Threshold voltage at CS –146 –130 –115 mV CS bias current FB = 3 V –120 µA CSG bias current FB = 3 V –35 µA ON TIMER, RT PIN tON - 1 On-time VIN = 12 V, RT = 50 kΩ 150 200 250 ns tON - 2 On-time VIN = 32 V, RT = 50 kΩ 75 ns tON - 3 On-time (current limit) LM25011 VIN = 12 V, RT = 50 kΩ 100 ns tON - 3 On-time (current limit) LM25011A VIN = 12 V, RT = 50 kΩ 200 ns tON - 4 On-time VIN = 12 V, RT = 301 kΩ 1020 ns tON - 5 On-time VIN = 9 V, RT = 30.9 kΩ 130 171 215 ns tON - 6 On-time VIN = 12 V, RT = 30.9 kΩ 105 137 170 ns tON - 7 On-time VIN = 16 V, RT = 30.9 kΩ 79 109 142 ns OFF TIMER tOFF Minimum off-time (LM25011) 90 150 208 ns Minimum off-time (LM25011A) 52 75 93 REGULATION COMPARATOR (FB PIN) VREF FB regulation threshold SS pin = steady state 2.46 2.51 2.56 V FB bias current FB = 3 V 100 nA POWER GOOD (PGD PIN) Threshold at FB, with respect to VREF FB increasing 91% 95% Threshold hysteresis 3.3% PGDVOL Low state voltage IPGD = 1 mA, FB = 0 V 125 180 mV PGDLKG Off state leakage VPGD = 7 V, FB = 3 V 0.1 µA THERMAL SHUTDOWN TSD Thermal shutdown Junction temperature increasing 155 °C Thermal shutdown hysteresis 20 °C

6.7 Typical Characteristics

Figure 1. Efficiency (Circuit of Figure 19) Figure 2. Efficiency at 2 MHz Figure 3. On-Time vs VIN and RT Figure 4. Voltage at the RT Pin Figure 5. Shutdown Current into VIN Figure 6. Operating Current into VIN

Figure 13. On-Time vs Temperature Figure 14. Minimum Off-Time vs Temperature

2.5V REGULATION COMPARATOR LM25011(A) PA CURRENT LIMIT COMPARATOR FINISHSTART OFF TIMER THERMAL SHUTDOWN FCIC CONTROL PGD 2.375V 0.8V R PGD CSG Power Good 125 mV UVLO SGND RS -CURRENT LIMIT THRESHOLD 6V to 42V C BYPC IN R T C SS C OUT VOUT R FB2 R FB2 Pre -Chg LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 www.ti.com Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation Feedback Copyright © 2009–2014, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The LM25011 constant on-time step-down switching regulator features all the functions needed to implement a low-cost, efficient buck bias power converter capable of supplying up to 2.0 A to the load. This high-voltage regulator contains an N-Channel buck switch, is easy to implement, and is available in a 10-pin VSSOP, PowerPAD power enhanced package. The operation of the regulator is based on a constant on-time control principle with the on-time inversely proportional to the input voltage. This feature results in the operating frequency remaining relatively constant with load and input voltage variations. The constant on-time feedback control principle requires no loop compensation resulting in very fast load transient response. The adjustable valley current limit detection results in a smooth transition from constant voltage to constant current when current limit is reached. To aid in controlling excessive switch current due to a possible saturating inductor, the on-time is reduced by approximately 40% when the current limit is detected. The Power Good output (PGD pin) indicates when the output voltage is within 5% of the expected regulation voltage. The LM25011 can be implemented to efficiently step-down higher voltages in non-isolated applications. Additional features include: low output ripple, VIN under-voltage lock-out, adjustable soft-start timing, thermal shutdown, gate drive pre-charge, gate drive under-voltage lock-out, and maximum duty-cycle limit.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Control Circuit Overview

The LM25011 buck regulator employs a control principle based on a comparator and a one-shot on-timer, with the output voltage feedback (FB) compared to an internal reference (2.51 V). If the FB voltage is below the reference, the internal buck switch is switched on for the one-shot timer period which is a function of the input voltage and the programming resistor (RT). Following the on-time, the switch remains off until the FB voltage falls below the reference, but never less than the minimum off-time forced by the off-time one-shot timer. When the FB pin voltage falls below the reference and the off-time one-shot period expires, the buck switch is then turned on for another on-time one-shot period.

R T = VOUT - (VIN x FS x 15 ns) FS x 4.1 x 10-11 - 500: tON = (VIN) 4.1 x 10-11 x (RT + 500:) + 15 ns FS =VOUT 2 x L1 x 1.19 x 1021 R L x RT DC = tON tON + tOFF == tON x FS VOUT VIN FS = VOUT (4.1 x 10-11 x (RT + 0.5k)) + (VIN x 15 ns) LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 www.ti.com SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation FeedbackCopyright © 2009–2014, Texas Instruments Incorporated Feature Description (continued) When in regulation, the LM25011 operates in continuous conduction mode at heavy load currents and discontinuous conduction mode at light load currents. In continuous conduction mode, the inductor current is always greater than zero and the operating frequency remains relatively constant with load and line variations. The minimum load current for continuous conduction mode is one-half of the ripple current amplitude of the inductor. The approximate operating frequency is calculated as follows: (1) The buck switch duty cycle is approximately equal to: (2) When the load current is less than one-half of the ripple current amplitude of the inductor, the circuit operates in discontinuous conduction mode. The off-time is longer than in continuous conduction mode while the inductor current is zero, causing the switching frequency to reduce as the load current is reduced. Conversion efficiency is maintained at light loads because the switching losses are reduced with the reduction in load and frequency. The approximate discontinuous operating frequency can be calculated as follows: (3) where RL = the load resistance, and L1 is the inductor in the circuit. The output voltage is set by the two feedback resistors (RFB1, RFB2 in the Functional Block Diagram ). The regulated output voltage is calculated as follows: VOUT = 2.51 V × (RFB1 + RFB2) / RFB1 (4) Ripple voltage, which is required at the input of the regulation comparator for proper output regulation, is generated internally in the LM25011, and externally when the LM25011A is used. In the LM25011 the ERM (emulated ripple mode) control circuit generates the required internal ripple voltage from the ripple waveform at the CS pin. The LM25011A, which is designed for higher frequency operation, requires additional ripple voltage which must be generated externally and provided to the FB pin. This is described in the Application and Implementation section.

7.3.2 On-Time Timer

The on-time for the LM25011/LM25011A is determined by the RT resistor and the input voltage (VIN), calculated from: (5) The inverse relationship with VIN results in a nearly constant frequency as VIN is varied. To set a specific continuous conduction mode switching frequency (FS), the RT resistor is determined from the following: (6) The on-time must be chosen greater than 90 ns for proper operation. Equation 1, Equation 5, and Equation 6 are valid only during normal operation; that is, the circuit is not in current limit. When the LM25011 operates in current limit, the on-time is reduced by approximately 40% (this feature is not present in LM25011A). This feature reduces the peak inductor current which may be excessively high if the load current and the input voltage are simultaneously high. This feature operates on a cycle-by-cycle basis until the load current is reduced and the

7.3.3 Current Limit

RS reduces to its threshold (VOUT is low due to current limiting). reduced, the inductor current increases until the lower peak of the inductor ripple current exceeds the threshold. Figure 15. Normal and Current Limit Operation

7.3.4 Ripple Requirements

through RS during the off-time. See Figure 16. Figure 16. CS Pin Waveform where ΔI is the inductor current ripple amplitude, and RS is the current-sense resistor at the CS pin. More ripple can be achieved by decreasing the inductor value. are explained in the External Components section.

7.3.5 N-Channel Buck Switch and Driver

driver circuit works in conjunction with an external bootstrap capacitor (CBST) and an internal high-voltage diode. bootstrap capacitor voltage.

7.3.6 Soft-Start

controlled manner. For proper operation, the soft-start capacitor should be no smaller than 1000 pF.

Figure 17. Startup Sequence

7.3.7 Power Good Output (PGD)

falling threshold for the PGD output to switch low is approximately 3.3% below the rising threshold. PGD Low Voltage vs Sink Current.

7.3.8 Thermal Shutdown

below 135°C (typical hysteresis = 20°C), normal operation resumes.

7.4 Device Functional Modes

7.4.1 Shutdown Function

the pin allows normal operation to resume. Figure 18. Shutdown Implementation

8 Application and Implementation

validate and test their design implementation to confirm system functionality.

8.1 Application Information

8.2 Typical Application

8.2.1 LM25011 Example Circuit

measures approximately 1.62 A at VIN = 8 V, and 1.69 A at VIN = 36 V. Figure 19. Example Circuit

8.2.1.1 Design Requirements

Table 1 shows the design parameters. Table 1. Design Parameters

R T =5 - (8V x 1MHz x 15 ns) 1MHz x 4.1 x 10-11 - 500:= 118.5 k: tOFF(min) = VIN(min) - VOUT VIN(min) x FS = 375 ns8V - 5V 8V x 1 MHz= tON(min) = VOUT VIN(max) x FS = 139 ns5V 36V x 1 MHz= LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 www.ti.com SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation FeedbackCopyright © 2009–2014, Texas Instruments Incorporated

8.2.1.2 Detailed Design Procedure

8.2.1.2.1 Custom Design with WEBENCH Tools

Click here to create a custom design using the LM25011 device with the WEBENCH® Power Designer. 1. Start by entering your VIN, VOUT and IOUT requirements. 2. Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments. 3. WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability. 4. In most cases, you will also be able to: – Run electrical simulations to see important waveforms and circuit performance, – Run thermal simulations to understand the thermal performance of your board, – Export your customized schematic and layout into popular CAD formats, – Print PDF reports for the design, and share your design with colleagues. 5. Get more information about WEBENCH tools at www.ti.com/webench.

8.2.1.2.2 External Components

The procedure for calculating the external components is illustrated with a design example using the LM25011. Referring to the Functional Block Diagram , the circuit is to be configured for the following specifications:

VOUT = 5 V
VIN = 8 V to 36 V
Minimum load current for continuous conduction mode IOUT(min) = 300 mA
Maximum load current IOUT(max) = 1.5 A
Switching frequency (FSW) = 1.0 MHz
Soft-start time = 5 ms RFB2 and RFB1: These resistors set the output voltage, and their ratio is calculated from: RFB2/RFB1 = (VOUT / 2.51 V) – 1 (8) For this example, RFB2/RFB1 = 0.992. RFB1 and RFB2 should be chosen from standard value resistors in the range of 1.0 kΩ to 10 kΩ which satisfy the above ratio. For this example, 4.99 kΩ is chosen for both resistors, providing a 5.02-V output. RT: This resistor sets the on-time and (by default) the switching frequency. First check that the desired frequency does not require an on-time or off-time shorter than the minimum allowed values (90 ns and 150, respectively). The minimum on-time occurs at the maximum input voltage. For this example: (9) The minimum off-time occurs at the minimum input voltage. For this example: (10) Both the on-time and off-time are acceptable because they are significantly greater than the minimum value for each. The RT resistor is calculated from Equation 6 using the minimum input voltage: (11) A standard value 118-kΩ resistor is selected. The minimum on-time calculates to 152 ns at VIN = 36 V, and the maximum on-time calculates to 672 ns at VIN = 8 V.

Duty Cycle = D = = = 13.9%VOUT VIN 36V L1(min) = tON(min) x (VIN(max) - VOUT ) IOR(max) = 7.85 PH LM25011,LM25011-Q1,LM25011A,LM25011A-Q1 SNVS617H –APRIL 2009–REVISED NOVEMBER 2014 www.ti.com Product Folder Links: LM25011 LM25011-Q1 LM25011A LM25011A-Q1 Submit Documentation Feedback Copyright © 2009–2014, Texas Instruments Incorporated L1: The parameters controlled by the inductor are the inductor current ripple amplitude (IOR), and the ripple voltage amplitude across the current sense resistor RS. The minimum load current is used to determine the maximum allowable ripple to maintain continuous conduction mode (the lower peak does not reach 0 mA). This is not a requirement of the LM25011, but serves as a guideline for selecting L1. For this example, the maximum ripple current should be less than: IOR(max) = 2 × IOUT(min) = 600 mAP-P (12) For applications where the minimum load current is zero, a good starting point for allowable ripple is 20% of the maximum load current. In this case substitute 20% of IOUT(max) for IOUT(min) in Equation 12. The ripple amplitude calculated in Equation 12 is then used in Equation 13: (13) A standard value 10-µH inductor is chosen. Using this inductor value, the maximum ripple current amplitude, which occurs at maximum VIN, calculates to 472 mAP-P, and the peak current is 1736 mA at maximum load current. Ensure the selected inductor is rated for this peak current. The minimum ripple current, which occurs at minimum VIN, calculates to 200 mAP-P. RS: The minimum current limit threshold is calculated at maximum load current using the minimum ripple current calculated above. The current limit threshold is the lower peak of the inductor current waveform when in current limit (see Figure 15). Current limit detection occurs when the voltage across the sense resistor (RS) reaches the current limit threshold. To allow for tolerances, the sense resistor value is calculated using the minimum threshold specification: RS = 115 mV / 1.4 A = 82 mΩ (15) The next smaller standard value, 80 mΩ, is selected. The next step is to ensure that sufficient ripple voltage occurs across RS with this value sense resistor. As mentioned in the Ripple Requirements section, a minimum of 15-mVP-P voltage ripple is required across the RS sense resistor during the off-time to ensure the regulation circuit operates properly. The ripple voltage is the product of the inductor ripple current amplitude and the sense resistor value. In this case, the minimum ripple voltage calculates to: VRIPPLE = ΔI × RS = 200 mA × 0.080 Ω = 16 mV (16) If the ripple voltage had calculated to less than 15 mVP-P, the inductor value would have to be reduced to increase the ripple current amplitude. This would have required a recalculation of ILIM and RS in the above equations. Because the minimum requirement is satisfied in this case, no change is necessary. The nominal current limit threshold calculates to 1.63 A. The minimum and maximum thresholds calculate to 1.44 A and 1.83 A, respectively, using the minimum and maximum limits for the current limit threshold specification. The load current is equal to the threshold current plus one-half of the ripple current. Under normal load conditions, the maximum power dissipation in RS occurs at maximum load current, and at maximum input voltage where the on-time duty cycle is minimum. In this design example, the minimum on-time duty cycle is: (17) At maximum load current, the power dissipation in RS is equal to: When in current limit the maximum power dissipation in RS calculates to Duty cycle is not included in this power calculation because the on-time duty cycle is typically <5% when in current limit. COUT: The output capacitor should typically be no smaller than 3.3 µF, although that is dependent on the frequency and the desired output characteristics. COUT should be a low ESR good-quality ceramic capacitor. Experimentation is usually necessary to determine the minimum value for COUT, as the nature of the load may require a larger value. A load which creates significant transients requires a larger value for COUT than a non- varying load.

ripple at VIN, because it is assumed the voltage source feeding VIN has some amount of source impedance. the maximum on-time, without letting the voltage at the VIN pin drop below a minimum operating level of 5.5 V. chip capacitor is recommended, and CBYP must be located close to the VIN and SGND pins. helps ensure a complete recharge during each off-time. transitions at the SW pin may affect the regulator operation due to the reverse recovery transients of the diode. where VF is the forward voltage drop of the diode, and D is the on-time duty cycle.

8.2.1.3 Application Curves

Figure 20. Efficiency (Circuit of Figure 19) Figure 21. Frequency vs VIN (Circuit of Figure 19)

8.2.2 Output Ripple Control

additional components to provide ripple at the FB pin with lower output ripple at VOUT. much ripple as needed to stabilize the switching frequency over the required input voltage.

8.2.2.1 Option A: Lowest Cost Configuration

ripple voltage injected at the FB pin. Figure 22. Option A – Lowest Cost Ripple Configuration

8.2.2.2 Option B: Intermediate VOUT Ripple Configuration

Figure 23. Option B – Intermediate Ripple Configuration

8.2.2.3 Option C: Minimum VOUT Ripple Configuration

The time constant Rr × Cr should be more than 8 to 10 times the switching period to generate a triangular

waveform at the junction of Rr, Cr and Cac.

The minimum ripple at FB (at minimum VIN) is equal to: VRIPPLE = (VIN(min) – VOUT) × TON(max) / (Rr x Cr).
The ripple capacitor Cr should much smaller than the ac coupling capacitor Cac. Typically Cac = 100 nF, Cr

= 1 nF, and Rr is chosen to satisfy conditions 1 and 2 above. Figure 24. Option C: Minimum Output Ripple Configuration

9 Power Supply Recommendations

small compared to the module input impedance to maintain the stability of the converter.

10 Layout

10.1 Layout Guidelines

The LM25011 regulation and current limit comparators are very fast, and respond to short-duration noise pulses. connection from CSG to the ground end of CIN should be as short and direct as possible.

10.2 Layout Example

Figure 25. Typical Layout

10.3 Power Dissipation

reduce the junction temperature.

11 Device and Documentation Support

11.1 Custom Design with WEBENCH Tools

Click here to create a custom design using the LM25011 device with the WEBENCH® Power Designer.

Start by entering your VIN, VOUT and IOUT requirements.
Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and

compare this design with other possible solutions from Texas Instruments.

WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real

time pricing and component availability.

In most cases, you will also be able to:

– Print PDF reports for the design, and share your design with colleagues.

Get more information about WEBENCH tools at www.ti.com/webench.

11.2 Receiving Notification of Documentation Updates

changed. For change details, review the revision history included in any revised document.

11.3 Related Links

resources, tools and software, and quick access to sample or buy. Table 2. Related Links

11.4 Trademarks

WEBENCH is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners.

11.5 Electrostatic Discharge Caution

during storage or handling to prevent electrostatic damage to the MOS gates.

11.6 Glossary

This glossary lists and explains terms, acronyms, and definitions.

12 Mechanical, Packaging, and Orderable Information

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www.ti.com 23-May-2025 PACKAGING INFORMATION Orderable part number Status (1) Material type (2) Package | Pins Package qty | Carrier RoHS (3) Lead finish/ Ball material (4) MSL rating/ Peak reflow (5) Op temp (°C) Part marking (6) LM25011AMY Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AMY.A Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AMYE Active Production HVSSOP (DGQ) | 10 250 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AMYE.A Active Production HVSSOP (DGQ) | 10 250 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AMYX Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AMYX.A Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SN9B LM25011AQ1MY/NOPB Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SZZA LM25011AQ1MY/NOPB.A Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SZZA LM25011AQ1MYX/NOPB Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SZZA LM25011AQ1MYX/NOPB.A Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SZZA LM25011MY/NOPB Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SVUB LM25011MY/NOPB.A Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SVUB LM25011MYX/NOPB Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SVUB LM25011MYX/NOPB.A Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SVUB LM25011Q1MY/NOPB Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SZFB LM25011Q1MY/NOPB.A Active Production HVSSOP (DGQ) | 10 1000 | SMALL T&R Yes SN Level-3-260C-168 HR -40 to 125 SZFB LM25011Q1MYX/NOPB Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SZFB LM25011Q1MYX/NOPB.A Active Production HVSSOP (DGQ) | 10 3500 | LARGE T&R Yes SN Level-3-260C-168 HR -40 to 125 SZFB (1) Status: For more details on status, see our product life cycle. (2) Material type: When designated, preproduction parts are prototypes/experimental devices, and are not yet approved or released for full production. Testing and final process, including without limitation quality assurance, reliability performance testing, and/or process qualification, may not yet be complete, and this item is subject to further changes or possible discontinuation. If available for ordering, purchases will be subject to an additional waiver at checkout, and are intended for early internal evaluation purposes only. These items are sold without warranties of any kind. (3) RoHS values: Yes, No, RoHS Exempt. See the TI RoHS Statement for additional information and value definition. (4) Lead finish/Ball material: Parts may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. Addendum-Page 1

www.ti.com 23-May-2025 (5) MSL rating/Peak reflow: The moisture sensitivity level ratings and peak solder (reflow) temperatures. In the event that a part has multiple moisture sensitivity ratings, only the lowest level per JEDEC standards is shown. Refer to the shipping label for the actual reflow temperature that will be used to mount the part to the printed circuit board. (6) Part marking: There may be an additional marking, which relates to the logo, the lot trace code information, or the environmental category of the part. Multiple part markings will be inside parentheses. Only one part marking contained in parentheses and separated by a "~" will appear on a part. If a line is indented then it is a continuation of the previous line and the two combined represent the entire part marking for that device. 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. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. OTHER QUALIFIED VERSIONS OF LM25011, LM25011-Q1 :

Catalog : LM25011
Automotive : LM25011-Q1 NOTE: Qualified Version Definitions:
Catalog - TI's standard catalog product
Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2024 TAPE AND REEL INFORMATION Reel Width (W1) REEL DIMENSIONS A0B0K0WDimension designed to accommodate the component lengthDimension designed to accommodate the component thicknessOverall width of the carrier tapePitch between successive cavity centersDimension designed to accommodate the component width TAPE DIMENSIONSK0 P1B0WA0Cavity QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE Pocket QuadrantsSprocket HolesQ1Q1Q2Q2Q3Q3Q4Q4User Direction of Feed P1ReelDiameter *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) (mm) (mm) (mm) (mm) W (mm) Pin1 Quadrant Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2024 TAPE AND REEL BOX DIMENSIONS Width (mm) W LH *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM25011AMY HVSSOP DGQ 10 1000 208.0 191.0 35.0 LM25011AMYE HVSSOP DGQ 10 250 208.0 191.0 35.0 LM25011AMYX HVSSOP DGQ 10 3500 356.0 356.0 36.0 LM25011AQ1MY/NOPB HVSSOP DGQ 10 1000 208.0 191.0 35.0 LM25011AQ1MYX/NOPB HVSSOP DGQ 10 3500 356.0 356.0 36.0 LM25011MY/NOPB HVSSOP DGQ 10 1000 208.0 191.0 35.0 LM25011MYX/NOPB HVSSOP DGQ 10 3500 356.0 356.0 36.0 LM25011Q1MY/NOPB HVSSOP DGQ 10 1000 208.0 191.0 35.0 LM25011Q1MYX/NOPB HVSSOP DGQ 10 3500 356.0 356.0 36.0 Pack Materials-Page 2

www.ti.com PACKAGE OUTLINE C 5.05

4.75 TYP

1.1 MAX

8X 0.5 10X 0.27 0.17 0.23

0.13 TYP

0.15 0.05 1.88 1.58 2.05 1.75 0.25 GAGE PLANE 0.7 0.4 A 3.1 2.9 NOTE 3 B 3.1 2.9 4214864/A 05/2020 PowerPAD - 1.1 mm max heightDGQ0010A PLASTIC SMALL OUTLINE NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed 0.15 mm per side. 4. This dimension does not include interlead flash. Interlead flash shall not exceed 0.25 mm per side. 5. Reference JEDEC registration MO-187, variation BA-T. PowerPAD is a trademark of Texas Instruments. TM 1 10

0.08 C A B

0.1 C SEE DETAIL A DETAIL A TYPICAL SCALE 3.700 EXPOSED THERMAL PAD

www.ti.com EXAMPLE BOARD LAYOUT (4.4)

0.05 MAX

0.05 MIN

8X (0.5) (2.2) NOTE 9 (3.1) NOTE 9 (1.88) (2.05) SOLDER MASK OPENING ( 0.2) TYP VIA (1.3) TYP (1.3) TYP (R0.05) TYP 4214864/A 05/2020 PowerPAD - 1.1 mm max heightDGQ0010A PLASTIC SMALL OUTLINE SYMM SYMM SEE DETAILS LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE:15X 5 6 SOLDER MASK OPENING METAL COVERED BY SOLDER MASK SOLDER MASK DEFINED PAD TM NOTES: (continued) 6. Publication IPC-7351 may have alternate designs. 7. Solder mask tolerances between and around signal pads can vary based on board fabrication site. 8. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature 9. Size of metal pad may vary due to creepage requirement. METALSOLDER MASK OPENING NON SOLDER MASK DEFINED SOLDER MASK DETAILS EXPOSED METAL SOLDER MASK OPENING METAL UNDER SOLDER MASK SOLDER MASK DEFINED EXPOSED METAL

www.ti.com EXAMPLE STENCIL DESIGN 8X (0.5) (4.4) (1.88) (2.05) BASED ON

0.125 THICK

(R0.05) TYP 4214864/A 05/2020 PowerPAD - 1.1 mm max heightDGQ0010A PLASTIC SMALL OUTLINE 1.59 X 1.730.175 1.72 X 1.870.150 1.88 X 2.05 (SHOWN)0.125 2.10 X 2.290.1 SOLDER STENCIL OPENING STENCIL THICKNESS NOTES: (continued) 10. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 11. Board assembly site may have different recommendations for stencil design. TM SOLDER PASTE EXAMPLE EXPOSED PAD 100% PRINTED SOLDER COVERAGE BY AREA SCALE:15X SYMM SYMM BASED ON

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Product Information

LM25011Q1MY/NOPB.A specifications and overview.

Summary

LM25011, LM25011-Q1, LM25011A, LM25011A-Q1 42-V 2-A Constant On-Time Switching Regulator With Adjustable Current Limit REVISED NOVEMBER 2014

Description

LM25011, LM25011-Q1, LM25011A, LM25011A-Q1 42-V 2-A Constant On-Time Switching Regulator With Adjustable Current Limit REVISED NOVEMBER 2014

Source title LM25011Q1MY/NOPB.A Datasheet(PDF) - Texas Instruments

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