LM26003MHX/NOPB National Semiconductor, LM26003MHX/NOPB Datasheet

IC REG BUCK SW 3A 20-TSSOP

LM26003MHX/NOPB

Manufacturer Part Number
LM26003MHX/NOPB
Description
IC REG BUCK SW 3A 20-TSSOP
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
Step-Down (Buck)r
Datasheet

Specifications of LM26003MHX/NOPB

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.25 ~ 35 V
Current - Output
3A
Frequency - Switching
150kHz ~ 500kHz
Voltage - Input
4 ~ 38 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
20-TSSOP Exposed Pad, 20-eTSSOP, 20-HTSSOP
Power - Output
3.1W
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
LM26003MHX

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM26003MHX/NOPB
Manufacturer:
ST
Quantity:
445
Part Number:
LM26003MHX/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
© 2010 National Semiconductor Corporation
3A Switching Regulator with High Efficiency Sleep Mode
General Description
The LM26003 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 ef-
ficiency under light-load conditions and current-mode control
for accurate regulation over a wide input voltage range. Qui-
escent current is reduced to 10.8 µA typically in shutdown
mode and less than 40 µA in sleep mode. Forced PWM mode
is also available to disable sleep mode.
The LM26003 can deliver up to 3A of continuous load current
with a fixed current limit, through the internal N-channel
switch. The part has a wide input voltage range of 4.0V to 38V
and can operate with input voltages as low as 3V during line
transients.
Operating frequency is adjustable from 150 kHz to 500 kHz
with a single resistor and can be synchronized to an external
clock.
Other features include Power good, adjustable soft-start, en-
able pin, input under-voltage protection, and an internal boot-
strap diode for reduced component count.
Typical Application Circuit
300676
LM26003/LM26003Q
Features
Applications
LM26003Q is an Automotive Grade product that is AEC-
Q100 grade 1 qualified (-40°C to +125°C operating
junction temperature)
High efficiency sleep mode
40 µA typical Iq in sleep mode
10.8 µA typical Iq in shutdown mode
3.0V minimum input voltage
4.0V to 38V continuous input range
1.5% reference accuracy
Cycle-by-cycle current limit
Adjustable Frequency (150 kHz to 500 kHz)
Synchronizable to an external clock
Power Good Flag
Forced PWM function
Adjustable Soft-start
TSSOP-20 exposed pad package
Thermal Shut Down
Automotive Telematics
Navigation systems
In-Dash Instrumentation
Battery Powered Applications
Stand-by power for home gateways/set-top boxes
November 29, 2010
30067601
www.national.com

Related parts for LM26003MHX/NOPB

LM26003MHX/NOPB Summary of contents

Page 1

... Other features include Power good, adjustable soft-start, en- able pin, input under-voltage protection, and an internal boot- strap diode for reduced component count. Typical Application Circuit © 2010 National Semiconductor Corporation LM26003/LM26003Q Features ■ LM26003Q is an Automotive Grade product that is AEC- Q100 grade 1 qualified (-40°C to +125°C operating junction temperature) ■ ...

Page 2

Connection Diagram Ordering Information Order Number Package Type LM26003MH TSSOP-20EXP LM26003MHX LM26003QMH TSSOP-20EXP LM26003QMHX *Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including defect detection methodologies. Reliability qualification is compliant with the requirements and ...

Page 3

Pin # Pin Name Description 16 VDD The output of the internal regulator. Bypass with a minimum 1.0 µF capacitor. 17 BOOT Bootstrap capacitor pin. Connect a 0.1 µF minimum ceramic capacitor from this pin generate the ...

Page 4

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Voltages from the indicated pins to GND: VIN SW (Note 7) VDD VBIAS FB BOOT PGOOD FREQ SYNC Electrical Characteristics over the junction temperature (T ) range of -40°C to +125°C. Unless otherwise stated, Vin = 12V. Minimum and Maximum limits J are guaranteed through test, design, or statistical correlation ...

Page 5

Symbol Parameter T Minimum Off-time OFFMIN T Minimum On-time ONMIN TH Sleep Mode Threshold Hysteresis SLEEP_HYS TH Wake Up Threshold WAKE I BOOT Pin Leakage Current BOOT Protection I Peak Current Limit LIMPK V Short Circuit Frequency Foldback FB_SC Threshold ...

Page 6

Typical Performance Characteristics 12V 25°C. J Efficiency vs Load Current (300 kHz) VFB vs Temperature IQ and IVBIAS vs Temperature (Sleep Mode) www.national.com Unless otherwise specified the following conditions apply: Vin = Efficiency vs Load Current (500 kHz) ...

Page 7

Startup Waveforms 30067647 Load Transient Response 30067646 UVLO Threshold vs Temperature (VDD = VIN) Peak Current Limit vs Temperature Normalized Switching Frequency vs Temperature (300kHz) 30067645 7 30067641 30067643 www.national.com ...

Page 8

Block Diagram www.national.com 8 30067603 ...

Page 9

Operation Description GENERAL The LM26003 is a current mode PWM buck regulator. At the beginning of each clock cycle, the internal high-side switch turns on, allowing current to ramp-up in the inductor. The in- ductor current is internally monitored during ...

Page 10

Iin = Dwake Where I is the gate drive current, calculated as ...

Page 11

During high over-current conditions, such as output short cir- cuit, the LM26003 employs frequency foldback as a second level of protection. If the feedback voltage falls below the short circuit threshold of 0.9V, operating frequency is reduced, thereby reducing average ...

Page 12

FIGURE 6. Off-Pulse Skipping Waveforms Vin = 3.5V, Vnom = 3.3V, fnom = 305 kHz UVLO is sensed at both VIN and VDD, and is activated when either voltage falls below 2.96V (typical). Although VDD is typically less than 200 ...

Page 13

Design Information EXAMPLE CIRCUIT Figure 7 shows a complete typical application schematic. The components have been selected based on the design criteria given in the following sections. SETTING OUTPUT VOLTAGE The output voltage is set by the ratio of a ...

Page 14

Where Re is the ESR of the output capacitors, and Vrip is a peak-to-peak value. This equation assumes that the output capacitors have some amount of ESR. It does not apply to ceramic output capacitors. If this method is used, ...

Page 15

Also keep in mind that the reverse leakage current of a Schottky diode increases with temperature and with reverse voltage. Reverse voltage equals roughly the in- put voltage in a buck converter. At hot, the diode reverse leakage ...

Page 16

Once the fp range is determined, R5 should be calculated using: 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 10 dB ...

Page 17

GND pin must be connected to ground. This quieter plane should be connected to the high current ground plane at a quiet location, preferably near the Vout ground as shown by the dashed line in Figure 11. The EP GND ...

Page 18

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted eTSSOP-20 Package 20-Lead Exposed Pad TSSOP Package NS Package Number MXA20A 18 ...

Page 19

Notes 19 www.national.com ...

Page 20

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