NSC LM2612BBPX, LM2612ABPX, LM2612ABP, LM2612BBP Datasheet

May 2002

LM2612
400mA Sub-miniature, Programmable, Step-Down DC-DC
Converter for Ultra Low-Voltage Circuits

LM2612 400mA Sub-miniature, Programmable, Step-Down DC-DC Converter for Ultra Low-Voltage

Circuits

General Description

The LM2612 step-down DC-DC converter is optimized for
powering ultra-low voltage circuits from a single Lithium-Ion
cell. It provides up to 400mA (300mA for B grade), over an
input voltage range of 2.8V to 5.5V. Pin programmable out­put voltages of 1.05V, 1.3V, 1.5V or 1.8V allow adjustment
for MPU voltage options without board redesign or external
feedback resistors.

The device has three pin-selectable modes for maximizing
battery life in mobile phones and similar portable applica­tions. Low-noise PWM mode offers 600kHz fixed-frequency
operation to reduce interference in RF and data acquisition
applications during full-power operation. In PWM mode, in­ternal synchronous rectification provides high efficiency
(91% typ. at 1.8V
the switching frequency in a range of 500kHz to 1MHz to
avoid noise from intermodulation with system frequencies.
Low-current hysteretic PFM mode reduces quiescent current
to 150 µA (typ.) during system standby. Shutdown mode
turns the device off and reduces battery consumption to

0.1µA(typ.).Additional features include soft start and current
overload protection.

The LM2612 is available in a 10 pin micro SMD packge. This
package uses National’s wafer level chip-scale micro SMD
technology and offers the smallest possible size. Only three
small external surface-mount components, an inductor and
two ceramic capacitors are required.

). A SYNC input allows synchronizing

OUT

Key Specifications

n Operates from a single LiION cell (2.8V to 5.5V)
n Pin programmable output voltage (1.05V, 1.3V, 1.5V and

1.8V)

n 400mA maximum load capability (300mA for B grade)

±

n

2% PWM mode DC output voltage precision

n 2mV typ PWM mode output voltage ripple
n 150 µA typ PFM mode quiescent current
n 0.1µA typ shutdown mode current
n Internal synchronous rectification for high PWM mode

efficiency (91% at 2.8V

n 600kHz PWM mode switching frequency
n SYNC input for PWM mode frequency synchronization

from 500kHz to 1MHz

, 1.8V

IN

OUT

)

Features

n Sub-miniature 10-pin micro SMD package
n Only three tiny surface-mount external components

required

n Uses small ceramic capacitors.
n Internal soft start
n Current overload protection
n No external compensation required

Applications

n Mobile Phones
n Hand-Held Radios
n Battery Powered Devices

Typical Application Circuit

20007102

© 2002 National Semiconductor Corporation DS200071 www.national.com

Connection Diagrams

LM2612

micro SMD package

TOP VIEW

20007104

BOTTOM VIEW

20007105

Ordering Information

Order Number Package Type NSC Package

Drawing

10-Pin micro SMD

LM2612ABP
LM2612BBP 250 Units, Tape and Reel
LM2612ABPX 3000 Units, Tape and Reel
LM2612BBPX 3000 Units, Tape and Reel

10-bump Wafer Level Chip Scale

(micro SMD)

BPA10VWB

250 Units, Tape and Reel

Supplied As

Pin Description

Pin Number(*) Pin Name Function

A1 FB Feedback Analog Input. Connect to the output at the output filter capacitor (Figure 1)
B1 VID1 Output Voltage Control Inputs. Set the output voltage using these digital inputs (see Table
C1 VID0
D1 SYNC/MODE Synchronization Input. Use this digital input for frequency selection or modulation control.

D2 EN Enable Input. Set this CMOS Schmitt trigger digital input high to VDD for normal

D3 PGND Power Ground
C3 SW Switching Node connection to the internal PFET switch and NFET synchronous rectifier.

B3 PVIN Power Supply Input to the internal PFET switch. Connect to the input filter capacitor

A3 VDD Analog Supply Input. If board layout is not optimum, an optional 0.1µF ceramic capacitor

A2 SGND Analog and Control Ground

(*) note the pin numbering scheme for the MicroSMD package was revised in April, 2002 to comform to JEDEC standard. Only the pin numbers were revised. No
changes to the physical location of the inputs/outputs were made. For reference purpose, the obsolete numbering has FB as pin 1, VID1 as pin 2, VID0 as pin3,
SYNC as pin 4, EN as pin 5, PGND as pin 6, SW as pin 7, PVIN as pin 8, VDD as pin 9 and SGND as pin 10.

1). The output defaults to 1.5V if these pins are unconnected.

Set:
SYNC/MODE = high for low-noise 600kHz PWM mode

SYNC/MODE = low for low-current PFM mode
SYNC/MODE = a 500kHz - 1MHz external clock for synchronization to an external clock in

PWM mode. See

operation. For shutdown, set low to SGND. Set EN low during power-up and other low
supply voltage conditions. (See

Connect to an inductor with a saturation current rating that exceeds the 850mA max
Switch Peak Current Limit specification of the LM2612 (

(

Figure 1

is suggested (

).

Synchronization and Operating Modes

Shutdown Mode

Figure 1

)

in the

in the

Device Information

Figure 1

Device Information

section.)

)

section.

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LM2612

Absolute Maximum Ratings (Note 1)

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

PVIN, VDD, to SGND −0.2V to +6V
PGND to SGND −0.2V to +0.2V
EN, SYNC/MODE, VID0, VID1 to

SGND −0.2V to +6V

Lead temperature
(Soldering, 10 sec.) 260˚C

Junction Temperature (Note 2) −25˚C to 125˚C
Minimum ESD Rating

Human body model, C = 100pF, R =

1.5 kΩ
Thermal Resistance (θ

)

JA

±

2.5kV

LM2612ABP & LM2612BBP (Note 3) 170˚C/W

FB, SW (GND −0.2V) to

(VDD +0.2V)

Storage Temperature Range −45˚C to +150˚C

Electrical Characteristics

Specifications with standard typeface are for TA=TJ= 25˚C, and those in bold face type apply over the full Operating Tem­perature Range (T
0V.

Symbol Parameter Conditions Min Typ Max Units

V

V

V

IN

FB

HYST

Input Voltage Range (Note5)PVIN = VDD = VID1 = VIN,

Feedback Voltage
(Note 6)

PFM Comparator Hysteresis
Voltage
(Note 7)

I

SHDN

I

Q1

I

Q2

R

DSON (P)

Shutdown Supply Current EN = 0V 0.1 3 µA
DC Bias Current into VDD

(V

OUT

Pin-Pin Resistance for P
FET

R

DSON (N)

Pin-Pin Resistance for N
FET

R

DSON , TC

FET Resistance
Temperature Coefficient

I

lim

Switch Peak Current Limit
(Note 8)

V

EN_H

EN Positive Going
Threshold Voltage
(Note 8)

V

EN_L

EN Negative Going
Threshold Voltage
(Note 8)

V

SYNC_H

SYNC/MODE Positive
Going Threshold Voltage

V

SYNC_L

SYNC/MODE Negative
Going Threshold Voltage

V

ID_H

V

ID0,VID1

Threshold Voltage

V

ID_L

V

ID0,VID1

Threshold Voltage

= −25˚C to +85˚C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 =

A=TJ

VID0 = 0V
VID0 = V
VID0 = V

, VID1 = V

IN

, VID1 = 0V 1.274 1.30 1.326

IN

IN

2.8 5.5 V

1.00 1.05 1.10

VID0 = 0V, VID1 = 0V 1.470 1.50 1.530
VID0 = 0V, VID1 = V

IN

1.764 1.8 1.836

PFM Mode (SYNC = 0V)

16 mV

set to 1.5V)

No-Load, PFM mode
(SYNC/MODE = 0V)

No-Load, PWM mode
(SYNC/MODE = V

)

IN

LM2612ABP & LM2612BBP

LM2612ABP & LM2612BBP

150 185

555 725

370 500 mΩ

330 500 mΩ

0.5 %/C

LM2612ABP 510 690 850
LM2612BBP 400 690 980

= 3.6V

V

DD

2.54 2.85 V

= 3.6V

V

DD

1.70 2.00 V

0.95 1.3 V

0.4 0.9 V

Positive Going

Negative Going

0.4 0.83 V

0.92 1.2 V

V

µA

mA

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Electrical Characteristics (Continued)

Specifications with standard typeface are for TA=TJ= 25˚C, and those in bold face type apply over the full Operating Tem-

LM2612

perature Range (T
0V.

Symbol Parameter Conditions Min Typ Max Units

I

VID

VID1, VID0 Pull Down
Current

f

sync

SYNC/MODE Clock
Frequency Range
(Note 10)

F

OSC

Internal Oscillator
Frequency

T

min

Minimum ON-Time of P FET
Switch in PWM Mode

Load Transient Response in
PWM Mode

Line Transient Response in
PFM Mode

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended
to be functional, but parameter specifications may not be guaranteed. For guaranteed specifications and associated test conditions, see the Min and Max limits and
Conditions in the Electrical Characteristics table. Electrical Characteristics table limits are guaranteed by production testing, design or correlation using standard
Statistical Quality Control methods. Typical (Typ) specifications are mean or average values from characterization at 25C and are not guaranteed.

Note 2: In PWM mode, Thermal shutdown will occur if the junction temperature exceeds the 150˚C maximum junction temperature of the device.
Note 3: Thermal resistance specified with 2 layer PCB(0.5/0.5 oz. cu).
Note 4: Thermal resistance specified with 3 layer PCB (2/1/1 oz. cu) and 12 vias 0.33mm diameter (see Application Note AN-1187).
Note 5: The LM2612 is designed for cell phone applications where turn-on after power-up is controlled by the system processor and internal UVLO (Under Voltage

LockOut) circuitry is unecessary. The LM2612 has no UVLO circuitry and should be kept in shutdown by holding the EN pin low until the input voltage exceeds 2.8V.
Although the LM2612 exhibited safe behavior during pre-production evaluation while enabled at low input voltages, this is not guaranteed.

Note 6: The feedback voltage is trimmed at the 1.5V output setting. The other output voltages result from the pin selection of the internal DAC’s divider ratios. The
precision for the feedback voltages is
if trimming at other voltages is desired.

Note 7: : The hysteresis voltage is the minimum voltage swing on FB that causes the internal feedback and control circuitry to turn the internal PFET switch on and
then off, during PFM mode.

Note 8: Current limit is built-in, fixed, and not adjustable. If the current limit is reached while the output is pulled below about 0.7V, the internal PFET switch turns
off for 2.5 µs to allow the inductor current to diminish.

Note 9: EN is a CMOS Schmitt trigger digital input with logic thresholds that scale with the supply voltage at the VDD pin. The nominal logic thresholds are
approximately 0.71VDD and 0.55VDD for the high and low thresholds respectively.

Note 10: SYNC driven with an external clock switching between V
external clock frequency. The LM2612 synchronizes to the rising edge of the external clock.

= −25˚C to +85˚C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 =

A=TJ

VID1, VID0 = 3.6V

1.8 µA

500 1000 kHz

LM2612ABP, PWM Mode
(SYNC = VIN)

LM2612BBP, PWM Mode
(SYNC = VIN)

468 600 732

450 600 750

200 ns

Circuit of
I

OUT

Circuit of
VIN= 3.0V to 3.6V Step
t

r=tp

±

2%, except for the 1.05V setting, which is 5%. Contact the Portable Power Applications group at National Semiconductor,

Figure 1

= 20mA to 200mA Step

±

25 mV

Figure 1

±

3mV

=10µs

and GND. When an external clock is present at SYNC, the IC is forced to PWM mode at the

IN

kHz

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Typical Operating Characteristics

LM2612ABP, Circuit of

L

= 10 µH, unless otherwise noted.

1

Quiescent Supply Current vs Temperature Quiescent Supply Current vs Supply Voltage

Shutdown Quiescent Current vs Temperature Output Voltage vs Temperature (PWM Mode)

Figure 1

,VIN= 3.6V, TA= 25˚C,

20007106 20007107

LM2612

20007108

Output Voltage vs Temperature (PFM Mode)

20007110 20007111

Output Voltage vs Supply Voltage

(V

= 1.8V, PWM Mode)

OUT

20007109

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Typical Operating Characteristics LM2612ABP, Circuit of

µH, unless otherwise noted. (Continued)

LM2612

Output Voltage vs Supply Voltage

(V

= 1.8V, PFM Mode)

OUT

20007112 20007113

Output Voltage vs Supply Voltage

(V

= 1.5V, PFM Mode)

OUT

Figure 1

,VIN= 3.6V, TA= 25˚C, L1=10

Output Voltage vs Supply Voltage

(V

= 1.5V, PWM Mode)

OUT

Output Voltage vs Supply Voltage

(V

= 1.3V, PWM Mode)

OUT

20007114

Output Voltage vs Supply Voltage

(V

= 1.3V, PFM Mode)

OUT

20007116 20007117

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Output Voltage vs Supply Voltage

(V

= 1.05V, PWM Mode)

OUT

20007115