LM25088MH-1/NOPB National Semiconductor, LM25088MH-1/NOPB Datasheet

IC CTLR BUCK NON-SYNC 16-TSSOP

LM25088MH-1/NOPB

Manufacturer Part Number
LM25088MH-1/NOPB
Description
IC CTLR BUCK NON-SYNC 16-TSSOP
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
Step-Down (Buck)r
Datasheet

Specifications of LM25088MH-1/NOPB

Design Resources
LM(2)5088-1/2 QS Component Calculator
Internal Switch(s)
No
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.21 ~ 45 V
Current - Output
10A
Frequency - Switching
200kHz, 500kHz
Voltage - Input
4.5 ~ 42 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
Primary Input Voltage
42V
No. Of Outputs
1
Output Voltage
1.2V
Output Current
10A
No. Of Pins
16
Operating Temperature Range
-40°C To +125°C
Msl
MSL 1 - Unlimited
Filter Terminals
SMD
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Other names
LM25088MH-1

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM25088MH-1/NOPB
Manufacturer:
NSC
Quantity:
800
© 2011 National Semiconductor Corporation
Wide Input Range Non-Synchronous Buck Controller
General Description
The LM25088 high voltage non-synchronous buck controller
features all the necessary functions to implement an efficient
high voltage buck converter using a minimum number of ex-
ternal components. The LM25088 can be configured to op-
erate over an ultra-wide input voltage range of 4.5V to 42V.
This easy to use controller includes a level shifted gate driver
capable of controlling an external N-channel buck switch. The
control method is based upon peak current mode control uti-
lizing an emulated current ramp. The use of an emulated
control ramp reduces noise sensitivity of the pulse-width mod-
ulation circuit, allowing reliable control of very small duty
cycles necessary in high input voltage/low output voltage ap-
plications. The LM25088 switching frequency is pro-
grammable from 50 kHz to 1 MHz.
The LM25088 is available in two versions: The LM25088-1
provides a +/-5% frequency dithering function to reduce the
conducted and radiated EMI, while the LM25088-2 provides
a versatile restart timer for overload protection. Additional
features include a low dropout bias regulator, tri-level enable
input to control shutdown and standby modes, soft-start and
oscillator synchronization capability. The device is available
in a thermally enhanced TSSOP-16EP pin package.
Simplified Application Schematic
300876
LM25088/LM25088Q
Features
Package
LM25088Q is an Automotive Grade product that is AEC-
Q100 grade 1 qualified (-40°C to +125°C operating
junction temperature)
Emulated current mode control
Drives external high-side N-channel MOSFET
Ultra-wide input voltage range from 4.5V to 42V
Low I
High duty cycle ratio feature for reduced dropout voltage
Spread spectrum EMI reduction (LM25088-1)
Hiccup timer for overload protection (LM25088-2)
Adjustable output voltage from 1.205V with 1.5% feedback
reference accuracy
Wide bandwidth error amplifier
Single resistor oscillator frequency setting
Oscillator synchronization capability
Programmable soft-start
High voltage, low dropout bias regulator
Thermal shutdown protection
TSSOP-16EP
Q
Shutdown and Standby modes
March 14, 2011
www.national.com
30087601

Related parts for LM25088MH-1/NOPB

LM25088MH-1/NOPB Summary of contents

Page 1

... The device is available in a thermally enhanced TSSOP-16EP pin package. Simplified Application Schematic © 2011 National Semiconductor Corporation LM25088/LM25088Q Features ■ LM25088Q is an Automotive Grade product that is AEC- Q100 grade 1 qualified (-40° ...

Page 2

... TSSOP-16EP, Dithering LM25088QMHX-1 TSSOP-16EP, Dithering LM25088MH-2 TSSOP-16EP, Restart LM25088MHX-2 TSSOP-16EP, Restart LM25088QMH-2 TSSOP-16EP, Restart LM25088QMHX-2 TSSOP-16EP, Restart *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 temperature grades defined in the AEC-Q100 standard. Automotive grade products are identified with the letter Q ...

Page 3

Pin Descriptions Pin(S) Name Description 1 VIN Input supply voltage 2 EN Enable input 3 SS Soft-start 4 RAMP Ramp control signal 5 RT/SYNC Internal oscillator frequency set input and synchronization input 6 GND Ground 7 COMP Output of the ...

Page 4

Pin(S) Name Description 15 BOOT Input for bootstrap capacitor An external capacitor is required between the BOOT and the SW pins to provide 16 VCC Output of the bias regulator VCC tracks VIN up to the regulation level (7.8V Typ). ...

Page 5

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN, VOUT to GND BOOT to GND SW to GND VCC to GND GND BOOT to SW Electrical Characteristics junction temperature (T ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical J correlation ...

Page 6

... Note 3: RAMP and COMP are output pins. As such they are not specified to have an external voltage applied. Note 4: Typical specifications represent the most likely parametric norm at 25°C operation. Note 5: For detailed information on soldering plastic MSOP packages refer to the Packaging Data Book available from National Semiconductor Corporation. www.national.com ...

Page 7

Typical Performance Characteristics Typical Application Circuit Efficiency VCC VCC Frequency vs R 30087640 30087642 RT 30087644 30087641 Shutdown Current 30087643 Frequency vs V VCC 30087645 www.national.com ...

Page 8

V vs Temperature FB Soft-Start vs Temperature Frequency vs Temperature www.national.com Forced-Off Time vs Temperature 30087646 Current-Limit vs Temperature 30087648 Error Amplifier Gain/Phase 30087650 8 30087647 30087649 30087651 ...

Page 9

Block Diagram FIGURE 1. Block Diagram 9 30087604 www.national.com ...

Page 10

Detailed Operation The LM25088 Wide Input Range Buck Controller features all the functions necessary to implement an efficient high voltage step-down converter using a minimum number of external components. The control method is based on peak current mode control utilizing ...

Page 11

Error Amplifier and PWM Comparator The internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision voltage reference (1.205V). The output of the error amplifier is connected to ...

Page 12

The sample & hold DC level illustrated in Figure 3 is derived from a measurement of the re-circulating (or free-wheeling) diode current. The diode current flows through the current sense resistor connected between the CS and CSG pins. The voltage ...

Page 13

Where 1/f and T is the forced off-time (280 OSC SW OFF (max) ns typical, 365 ns maximum); f and T SW frequency and oscillator period, respectively. From the above equation, it can be seen that for a ...

Page 14

FIGURE 6. Conducted Emissions Measured at the Input of a LM25088 Based Buck Converter Figure 6 shows the conducted emissions on the LM25088 evaluation board input power line. It can be seen from the above picture that, the peak emissions ...

Page 15

FET when it is turned ON, if the V exceeds 1.5V, the comparator turns of the buck DS FET immediately. This feature will help protect the buck FET in catastrophic conditions such ...

Page 16

Soft-Start The soft-start (SS) feature forces the output to rise linearly until it reaches the steady-state operating voltage set by the feedback resistors. The LM25088 will regulate the FB pin to the SS pin voltage or the internal 1.205V reference, ...

Page 17

The maximum ripple current occurs at the maximum input voltage. Typically selected between 20% and 40 the full load current. Higher ripple current will result in a small- er inductor. However, it places more burden on ...

Page 18

FIGURE 10. Additional Slope Compensation for VOUT > 5V OUTPUT CAPACITORS The output capacitors smooth the inductor current ripple and provide a source of charge for load transient conditions. The output capacitor selection is primarily dictated by the following specifications: ...

Page 19

OUTPUT VOLTAGE DIVIDER R and R set the output voltage level, the ratio of these FB1 FB2 resistors can be calculated from: 1.62 kΩ was chosen for R in this design which results in a FB1 R value of 5.11 ...

Page 20

ERROR AMPLIFIER COMPENSATION and C configure the error amplifier gain COMP COMP HF characteristics to accomplish a stable voltage loop gain. One advantage of current mode control is the ability of to close the loop with only ...

Page 21

PCB BOARD LAYOUT AND THERMAL CONSIDERATIONS In a buck regulator there are two loops where currents are switched very fast. The first loop starts from the input capac- itors, through the buck MOSFET, to the inductor then out to the ...

Page 22

www.national.com 22 ...

Page 23

23 www.national.com ...

Page 24

Bill of Materials for LM25088-1 and LM25088-2 Evaluation Boards Part Value Package C1,C2,C3,C4 2.2µF ,C5 C6,C19 0.1µF C7 1µF C8,C11 100pF C9 270pF C13 0.1µF C10 0.022µF C12 0.015µF C15 470µF 0.327x0.327x0.3 C17,C18 47µF C20 1000pF C16 NU 0.327x0.327x0.3 C21 ...

Page 25

Part Value Package J1,J2,J3,J4 Terminal_Turret TP1,TP2 Slotted test point U1 PWM IC TSSOP16_EP Manufacturer Manufacturer Part Number Description Keystone 1509 Keystone 1040 National LM25088-1/LM25088-2 25 Terminal, Turret Terminal test point slotted ECM Buck Controller www.national.com ...

Page 26

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 16-Lead TSSOP-EP Package NS Package Number MXA16A 26 ...

Page 27

Notes 27 www.national.com ...

Page 28

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

Related keywords