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LM26001

BOOT

COMP

VDD

GND

FPWM

FREQ

SYNC

PGOOD

VIN

144

VIN

VOUT

VIN

VBIAS

1 12

VDD

SYNC

LM26001, LM26001Q

www.ti.com

SNVS430G –MAY 2006–REVISED MAY 2006

LM26001/LM26001Q 1.5A Switching Regulator with High Efficiency Sleep Mode

Check for Samples: LM26001, LM26001Q

FEATURES

DESCRIPTION

The LM26001 is a switching regulator designed for

• LM26001Q is an Automotive Grade Product

the high efficiency requirements of applications with

that is AEC-Q100 Grade 1 Qualified (-40°C to

stand-by modes. The device features a low-current

+125°C Operating Junction Temperature)

sleep mode to maintain efficiency under light-load

• High Efficiency Sleep Mode

conditions and current-mode control for accurate

regulation over a wide input voltage range. Quiescent

• 40 µA Typical Iq in Sleep Mode

current is reduced to 10 µA typically in shutdown

• 10 µA Typical Iq in Shutdown Mode

mode and less than 40 µA in sleep mode. Forced

• 3.0V Minimum Input Voltage

PWM mode is also available to disable sleep mode.

• 4.0V to 38V Continuous Input Range

The LM26001 can deliver up to 1.5A of continuous

• 1.5% Reference Accuracy

load current with a fixed current limit, through the

internal N-channel switch. The part has a wide input

• Cycle-by-Cycle Current Limit

voltage range of 4.0V to 38V and can operate with

• Adjustable Frequency (150 kHz to 500 kHz)

input voltages as low as 3V during line transients.

• Synchronizable to an External Clock

Operating frequency is adjustable from 150 kHz to

• Power Good Flag

500 kHz with a single resistor and can be

• Forced PWM Function

synchronized to an external clock.

• Adjustable Soft-Start

Other features include Power good, adjustable soft-

• HTSSOP-16 Exposed Pad Package

start, enable pin, input under-voltage protection, and

an internal bootstrap diode for reduced component

• Thermal Shut Down

count.

APPLICATIONS

• Automotive Telematics

• Navigation Systems

• In-Dash Instrumentation

• Battery Powered Applications

• Stand-by Power for Home Gateways/Set-top

Boxes

Typical Application Circuit

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (28 pages)

PAGE 1
LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 LM26001/LM26001Q 1.5A Switching Regulator with High Efficiency Sleep Mode Check for Samples: LM26001, LM26001Q FEATURES DESCRIPTION • The LM26001 is a switching regulator designed for the high efficiency requirements of applications with stand-by modes. The device features a low-current sleep mode to maintain efficiency under light-load conditions and current-mode control for accurate regulation over a wide input voltage range.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Connection Diagram VIN 1 16 SW VIN 2 15 SW PGOOD 3 14 BOOT EN 4 13 VDD SS 5 12 VBIAS COMP 6 FB 7 11 SYNC 10 FPWM 9 FREQ GND 8 Exposed Pad Connect to GND Figure 1. Top View 16-Lead Plastic HTSSOP PIN DESCRIPTIONS Pin # Pin Name 1 VIN Power supply input Description 2 VIN Power supply input 3 PGOOD 4 EN Enable is an analog level input pin. When pulled below 0.8V, the device enters shutdown mode.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 Absolute Maximum Ratings (1) (2) Voltages from the indicated pins to GND Recommended Lead Temperature ESD Susceptibility (5) (1) (2) (3) (4) (5) VIN -0.3V to 40V SW (3) -0.5V to 40V VDD -0.3V to 7V VBIAS -0.3V to 10V FB -0.3V to 6V BOOT SW-0.3V to SW+7V PGOOD -0.3V to 7V FREQ -0.3V to 7V SYNC -0.3V to 7V EN -0.3V to 40V FPWM -0.3V to 7V SS -0.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Electrical Characteristics Specifications in standard type are for TJ = 25°C only, and limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Unless otherwise stated, Vin=12V. Minimum and Maximum limits are ensured through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 Electrical Characteristics (continued) Specifications in standard type are for TJ = 25°C only, and limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Unless otherwise stated, Vin=12V. Minimum and Maximum limits are ensured through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Typical Performance Characteristics Unless otherwise specified the following conditions apply: Vin = 12V, TJ = 25°C. VFB vs Vin (IDC = 300 mA) 1.236 1.236 1.234 1.235 VFB (V) VFB (V) VFB vs Temperature 1.232 1.230 1.234 1.233 1.228 -40 -20 1.232 0 20 40 60 0 80 100 120 140 5 10 15 TEMPERATURE (ºC) Figure 2. 25 30 35 40 Figure 3.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 Typical Performance Characteristics (continued) Unless otherwise specified the following conditions apply: Vin = 12V, TJ = 25°C. Short Circuit Foldback Frequency vs VFB (325 kHz nominal) Peak Current Limit vs Temperature 350 SWITCHING FREQUENCY (kHz) 3.0 ILIM PEAK (A) 2.8 2.6 2.4 2.2 2.0 -40 -20 0 20 40 60 300 250 200 150 100 50 0 0.2 80 100 120 140 0.4 0.6 TEMPERATURE (ºC) Figure 8.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified the following conditions apply: Vin = 12V, TJ = 25°C. Low Input Voltage Dropout Nominal VOUT = 5V 500 1A 125°C VIN-VOUT DROPOUT (mV) 450 400 1A 25°C 350 300 1A -40°C 250 200 150 40mA -40°C 100 40mA 25 to 125°C 50 0 3 3.5 4 4.5 VIN (V) 5 5.5 Figure 14.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 BLOCK DIAGRAM VIN 5 PA BG IREF TSD SD on LDO UVLO VDD_low VDD qn EN Switchover control fpwm VBIAS LG FPWM wake + - BG VREG Sleep Reset 0.6V + - Sleep Set sleep FPWM / Sleep Peak Current Control EA + FB + + blanking COMP 0.9V BOOT V clamp BG + 0.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Vout 10 mV/Div IL 500 mA/Div ID 1A/Div VSW 5V/Div 1 Ps/DIV Figure 15. PWM Waveforms 1A Load, Vin = 12V SLEEP MODE In light load conditions, the LM26001 automatically switches into sleep mode for improved efficiency. As loading decreases, the voltage at FB increases and the COMP voltage decreases. When the COMP voltage reaches the 0.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 250 200 500 kHz IDC (mA) 150 100 330 kHz 22 PH 15 PH 22 PH 50 15 PH 0 10 0 20 30 40 VIN (V) Figure 17. Sleep Mode Threshold vs Vin Vout = 3.3V Below the sleep threshold, decreasing load current results in longer sleep cycles, which can be quantified as shown below: Dwake = Iload/Isleep (2) Where Dwake is the percentage of time awake when the load current is below the sleep threshold.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com ENABLE The LM26001 provides a shutdown function via the EN pin to disable the device when the output voltage does not need to be maintained. EN is an analog level input with typically 120 mV of hysteresis. The device is active when the EN pin is above 1.2V (typical) and in shutdown mode when EN is below this threshold. When EN goes high, the internal VDD regulator turns on and charges the VDD capacitor. When VDD reaches 3.
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LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 If the FB voltage falls below the frequency foldback threshold during frequency synchronized operation, the SYNC function is disabled. Operating frequency versus FB voltage in short circuit conditions is shown in the Typical Performance Characteristics section.
PAGE 14
LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com If VBIAS drops below 2.9V (typical), the device automatically switches over to supply the internal bias voltage from Vin. LOW VIN OPERATION AND UVLO The LM26001 is designed to remain operational during short line transients when input voltage may drop as low as 3.0V. Minimum nominal operating input voltage is 4.0V. Below this voltage, switch RDS(ON) increases, due to the lower gate drive voltage from VDD.
PAGE 15
LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 VIN : 4V - 38V C1 3.3 PF 50V + C2 47 PF 50V 1 2 3 PGOOD R4 200k 4 EN VDD 11 5 SYNC R6 10k VIN VBIAS VIN SW PGOOD SW EN BOOT LM26001 SYNC R3 120k 1% SS C4 0.1 PF D1 3A 60V R1 56k 1% + C6 100 PF 12 m: 7 COMP FPWM 14 VOUT : 3.3V FB FREQ 10 16 15 9 C5 10 nF L 22 PH 3.5A 12 VDD EP 17 GND 6 13 Ref # C8 4.
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LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com For example, at a maximum load of 1.5A and a ripple content of 40%, peak inductor current is equal to 1.8A which is safely below the minimum current limit of 1.85A. By increasing the inductor size, ripple content and peak inductor current are lowered, which increases the current limit margin. The size of the output inductor can also be determined using the desired output ripple voltage, Vrip.
PAGE 17
LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 BOOTSTRAP The drive voltage for the internal switch is supplied via the BOOT pin. This pin must be connected to a ceramic capacitor, Cboot, from the switch node, shown as C4 in the typical application. The LM26001 provides the VDD voltage internally, so no external diode is needed. A maximum value of 0.1 uF is recommended for Cboot. Values smaller than 0.
PAGE 18
LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com The control-output transfer function consists of one pole (fp), one zero (fz), and a double pole at fn (half the switching frequency). Referring to Figure 22, the following should be done to create a -20dB /decade roll-off of the loop gain: 1. Place a pole at 0Hz (fpc) 2. Place a zero at fp (fzc) 3. Place a second pole at fz (fpc1) GAIN (dB) The resulting feedback (compensation) bode plot is shown below in Figure 23.
PAGE 19
LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 Where B is the desired feedback gain in v/v between fp and fz, and gm is the transconductance of the error amplifier. A gain value around 10dB (3.3v/v) is generally a good starting point. Bandwidth increases with increasing values of R5. 3. Next, place a zero (fzc) near fp using C8.
PAGE 20
LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com Vin Vout + GND SW EP GND Figure 25. Example PCB Layout It is a good practice to connect the EP, GND pin, and small signal components (COMP, FB, FREQ) to a separate ground plane, shown in Figure 25 as EP GND, and in the schematics as a signal ground symbol. Both the exposed pad and the GND pin must be connected to ground.
PAGE 21
LM26001, LM26001Q www.ti.com SNVS430G – MAY 2006 – REVISED MAY 2006 If the power dissipation remains above the maximum allowable level, device temperature will continue to rise. When the junction temperature exceeds its maximum, the LM26001 engages Thermal Shut Down (TSD). In TSD, the part remains in a shutdown state until the junction temperature falls to within normal operating limits. At this point, the device restarts in soft-start mode.
PAGE 22
LM26001, LM26001Q SNVS430G – MAY 2006 – REVISED MAY 2006 www.ti.com REVISION HISTORY Changes from Revision F (April 2013) to Revision G • 22 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 7-Oct-2013 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.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ HTSSOP PWP 16 2500 330.0 12.4 LM26001QMXAX/NOPB HTSSOP PWP 16 2500 330.0 12.4 LM26001MXAX/NOPB Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 6.95 8.3 1.6 8.0 12.0 Q1 6.95 8.3 1.6 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM26001MXAX/NOPB HTSSOP PWP 16 2500 367.0 367.0 35.0 LM26001QMXAX/NOPB HTSSOP PWP 16 2500 367.0 367.0 35.
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MECHANICAL DATA PWP0016A MXA16A (Rev A) www.ti.
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