NSC LM2622MM-ADJ, LM2622EVAL, LM2622-ADJMWC, LM2622MMX-ADJ Datasheet

LM2622
600kHz/1.3MHz Step-up PWM DC/DC Converter

General Description

The LM2622 is a step-up DC/DC converter with a 1.6A, 0.2Ω
internal switch and pin selectable operating frequency. With
the ability to convert 3.3V to multiple outputs of 8V, -8V, and
23V, the LM2622 is an ideal part for biasing TFT displays.
The LM2622 can be operated at switching frequencies of
600kHz and 1.3MHz allowingforeasyfilteringandlownoise.
An external compensation pin gives the user flexibility in
setting frequency compensation, which makes possible the
use of small, low ESR ceramic capacitors at the output. The
LM2622 is available in a low profile 8-lead MSOP package.

Features

n 1.6A, 0.2Ω, internal switch
n Operating voltage as low as 2.0V

n 600kHz/1.3MHz pin selectable frequency operation
n Over temperature protection
n 8-Lead MSOP package

Applications

n TFT Bias Supplies
n Handheld Devices
n Portable Applications
n GSM/CDMA Phones
n Digital Cameras

Typical Application Circuit

10127331

600 kHz Operation

October 2001

LM2622 600kHz/1.3MHz Step-up PWM DC/DC Converter

© 2001 National Semiconductor Corporation DS101273 www.national.com

Connection Diagram

Top View

10127304

8-Lead Plastic MSOP

NS Package Number MUA08A

Ordering Information

Order Number Package Type NSC Package

Drawing

Supplied As Package ID

LM2622MM-ADJ MSOP-8 MUA08A 1000 Units, Tape and

Reel

S18B

LM2622MMX-ADJ MSOP-8 MUA08A 3500 Units, Tape and

Reel

S18B

Pin Description

Pin Name Function

1V

C

Compensation network connection. Connected to the output of the voltage error amplifier.
2 FB Output voltage feedback input.
3 SHDN

Shutdown control input, active low.
4 GND Analog and power ground.
5 SW Power switch input. Switch connected between SW pin and GND pin.
6V

IN

Analog power input.
7 FSLCT Switching frequency select input. V

IN

= 1.3MHz. Ground = 600kHz.

8 NC Connect to ground.

LM2622

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Block Diagram

10127303

LM2622

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

V

IN

12V
SW Voltage 18V
FB Voltage 7V
V

C

Voltage 7V

SHDN Voltage

7V
FSLCT 12V
Maximum Junction

Temperature

150˚C

Power Dissipation(Note 2) Internally Limited
Lead Temperature 300˚C

Vapor Phase (60 sec.) 215˚C
Infrared (15 sec.) 220˚C

ESD Susceptibility
(Note 3)

Human Body Model 2kV
Machine Model 200V

Operating Conditions

Operating Junction
Temperature Range (Note 4) −40˚C to +125˚C

Storage Temperature −65˚C to +150˚C
Supply Voltage 2V to 12V

Electrical Characteristics

Specifications in standard type face are for TJ= 25˚C and those with boldface type apply over the full Operating Tempera­ture Range (T

J

= −40˚C to +125˚C)Unless otherwise specified. VIN=2.0V and IL= 0A, unless otherwise specified.

Symbol Parameter Conditions

Min

(Note 4)

Typ

(Note 5)

Max

(Note 4)

Units

I

Q

Quiescent Current FB = 0V (Not Switching) 1.3 2.0 mA

V

SHDN

=0V 5 10 µA

V

FB

Feedback Voltage 1.2285 1.26 1.2915 V

I

CL

(Note 6) Switch Current Limit VIN= 2.7V (Note 7) 1.0 1.65 2.3 A

∆V

O

/∆I

LOAD

Load Regulation VIN= 3.3V 6.7 mV/A

%V

FB

/∆VINFeedback Voltage Line

Regulation

2.0V ≤ VIN≤ 12.0V 0.013 0.1 %/V

I

B

FB Pin Bias Current (Note 8) 0.5 20 nA

V

IN

Input Voltage Range 212V

g

m

Error Amp Transconductance ∆I = 5µA 40 135 290 µmho

A

V

Error Amp Voltage Gain 135 V/V

D

MAX

Maximum Duty Cycle 78 85 %

f

S

Switching Frequency FSLCT = Ground 480 600 720 kHz

FSLCT = V

IN

1 1.25 1.5 MHz

I

SHDN

Shutdown Pin Current V

SHDN=VIN

0.01 0.1 µA

V

SHDN

=0V −0.5 -1

I

L

Switch Leakage Current VSW= 18V 0.01 3 µA

R

DSON

Switch R

DSON

VIN= 2.7V, ISW= 1A 0.2 0.4 Ω

Th

SHDN

SHDN Threshold Output High 0.9 0.6 V

Output Low 0.6 0.3 V

UVP On Threshold 1.8 1.92 2.0 V

Off Threshold 1.7 1.82 1.9 V

θ

JA

Thermal Resistance Junction to Ambient(Note 9) 235 ˚C/W

Junction to Ambient(Note 10) 225
Junction to Ambient(Note 11) 220
Junction to Ambient(Note 12) 200
Junction to Ambient(Note 13) 195

Note 1: Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to
be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, T

J

(MAX), the junction-to-ambient thermal resistance, θJA,

and the ambient temperature, T

A

. See the Electrical Characteristics table for the thermal resistance of various layouts. The maximum allowable power dissipation

at any ambient temperature is calculated using: P

D

(MAX) = (T

J(MAX)−TA

)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die

temperature, and the regulator will go into thermal shutdown.

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Electrical Characteristics (Continued)

Note 3: The human body model is a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged

directly into each pin.
Note 4: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are 100%

production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to
calculate Average Outgoing Quality Level (AOQL).

Note 5: Typical numbers are at 25˚C and represent the most likely norm.
Note 6: Duty cycle affects current limit due to ramp generator.
Note 7: Current limit at 0% duty cycle. See TYPICAL PERFORMANCE section for Switch Current Limit vs. V

IN

Note 8: Bias current flows into FB pin.
Note 9: Junction to ambient thermal resistance (no external heat sink) for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit.

See ’Scenario ’A’’ in the Power Dissipation section.
Note 10: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately

0.0191 sq. in. of copper heat sinking. See ’Scenario ’B’’ in the Power Dissipation section.
Note 11: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately

0.0465 sq. in. of copper heat sinking. See ’Scenario ’C’’ in the Power Dissipation section.
Note 12: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately

0.2523 sq. in. of copper heat sinking. See ’Scenario ’D’’ in the Power Dissipation section.
Note 13: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately

0.0098 sq. in. of copper heat sinking on the top layer and 0.0760 sq. in. of copper heat sinking on the bottom layer, with three 0.020 in. vias connecting the planes.
See ’Scenario ’E’’ in the Power Dissipation section.

Typical Performance Characteristics

Efficiency vs. Load Current

(V

OUT

= 8V, fS= 600 kHz)

Efficiency vs. Load Current

(V

OUT

= 8V, fS= 1.3 MHz)

10127326 10127325

Switch Current Limit vs. Temperature

(V

IN

= 3.3V, V

OUT

= 8V) Switch Current Limit vs. V

IN

10127320

10127322

LM2622

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