LM2612BL
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 out-
put 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 applica-
tions. 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, in-
ternal synchronous rectification provides high efficiency
(91% typ. at 1.8V
OUT
). A SYNC input allows synchronizing
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 160 A (typ.) during system standby. Shutdown mode
turns the device off and reduces battery consumption to
0.02A (typ.). Additional features include soft start and cur-
rent 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.
Key Specifications
n
Operates from a single LiION cell (2.8V to 5.5V)
n
Internal synchronous rectification for high PWM mode
efficiency
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
5mV typ PWM mode output voltage ripple
n
160 A typ PFM mode quiescent current
n
0.02A typ shutdown mode current
n
600kHz PWM mode switching frequency
n
SYNC input for PWM mode frequency synchronization
from 500kHz to 1MHz
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
n
Thermal shutdown protection
Applications
n
Mobile Phones
n
Hand-Held Radios
n
Battery Powered Devices
Typical Application Circuit
20041802
December 2002
LM2612BL
400mA
Sub-miniature,
Programmable,
Step-Down
DC-DC
Converter
for
Ultra
Low-V
oltage
Circuits
2002 National Semiconductor Corporation
DS200418
www.national.com
Connection Diagrams
micro SMD package
20041804
TOP VIEW
20041805
BOTTOM VIEW
Ordering Information
Order Number
Package Type
NSC Package
Marking(*)
Supplied As
10-Pin micro SMD
LM2612ABL
BLP106WB
10-bump Wafer Level Chip Scale
(micro SMD)
XYTT IS41A
250 Units, Tape and Reel
LM2612BBL
XYTT IS41B
250 Units, Tape and Reel
LM2612ABLX
XYTT IS41A
3000 Units, Tape and Reel
LM2612BBLX
XYTT IS41B
3000 Units, Tape and Reel
(*) XY - denotes the date code marking (2 digit) in production
TT - refers to die run/lot traceability for production
I - pin one indication
S - Product line designator
Note the Package Marking may change over the course of production time without notice
Order Number
Package Type
NSC Package
Marking(*)
Supplied As
10-Pin micro SMD
LM2612ATL
TLP106WA
10-bump Wafer Level Chip Scale
(micro SMD)
XYTT IS41A
250 Units, Tape and Reel
LM2612BTL
XYTT IS41B
250 Units, Tape and Reel
LM2612ATLX
XYTT IS41A
3000 Units, Tape and Reel
LM2612BTLX
XYTT IS41B
3000 Units, Tape and Reel
(*) XY - denotes the date code marking (2 digit) in production
TT - refers to die run/lot traceability for production
I - pin one indication
S - Product line designator
Note the Package Marking may change over the course of production time without notice
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
1). The output defaults to 1.5V if these pins are unconnected.
C1
VID0
D1
SYNC/MODE
Synchronization Input. Use this digital input for frequency synchronization or modulation
control. Set:
SYNC/MODE = high for low-noise 600kHz PWM mode
SYNC/MODE = low for low-current PFM mode
SYNC/MODE = 500kHz - 1MHz external clock for synchronization to an external clock in
PWM mode. See Synchronization and Operating Modes in the Device Information section.
D2
EN
Enable Input. For shutdown, set low to SGND.(See Shutdown Mode in the Device
Information section.)
D3
PGND
Power Ground
LM2612BL
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2
Pin Description
(Continued)
Pin Number
Pin Name
Function
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
(Figure 1).
A3
VDD
Analog Supply Input. If board layout is not optimum, an optional 0.1F ceramic capacitor
is suggested (Figure 1)
A2
SGND
Analog and Control Ground
(*) Note that the pin numbering scheme for the Micro SMD package was revised in April, 2002 to conform 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 obselete numbering had FB as pin 1, VID1 as pin 2, VID0 as pin
3, 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.
LM2612BL
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3
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
FB, SW
(GND -0.2V) to
(VDD +0.2V)
Storage Temperature Range
-45C to +150C
Lead temperature
(Soldering, 10 sec.)
260C
Junction Temperature (Note 2)
-25C to 125C
Minimum ESD Rating
Human body model, C = 100pF, R =
1.5 k
2kV
Thermal Resistance (
JA
)
LM2612ABL/LM2612ATL &
LM2612BBL/LM2612BTL(Note 3)
140C/W
Electrical Characteristics
Specifications with standard typeface are for T
A
= T
J
= 25C, and those in bold face type apply over the full Operating Tem-
perature Range (T
A
= T
J
= -25C to +85C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 =
0V.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
IN
Input Voltage Range (Note
4)
PVIN = VDD = VID1 = V
IN
,
VID0 = 0V
2.8
5.5
V
V
FB
Feedback Voltage
(Note 5)
VID0 = V
IN
, VID1 = V
IN
1.029
1.05
1.071
V
VID0 = V
IN
, VID1 = 0V
1.274
1.30
1.326
VID0 = 0V, VID1 = 0V
1.470
1.50
1.530
VID0 = 0V, VID1 = V
IN
1.764
1.8
1.836
V
HYST
PFM Comparator Hysteresis
Voltage
(Note 6)
PFM Mode (SYNC = 0V)
25
mV
I
SHDN
Shutdown Supply Current
EN = 0V
0.02
3
A
I
Q1
DC Bias Current into VDD
No switching, PFM mode
(SYNC/MODE = 0V)
160
195
A
I
Q2
No switching, PWM mode
(SYNC/MODE = V
IN
)
605
725
R
DSON (P)
Pin-Pin Resistance for P
FET
395
550
m
R
DSON (N)
Pin-Pin Resistance for N
FET
325
500
m
R
DSON , TC
FET Resistance
Temperature Coefficient
0.5
%/C
I
lim
Switch Peak Current Limit
(Note 7)
LM2612ABL/LM2612ATL
510
710
850
mA
LM2612BBL/LM2612BTL
400
710
980
V
EN_H
EN Positive Going
Threshold Voltage
0.95
1.3
V
V
EN_L
EN Negative Going
Threshold Voltage
0.4
0.80
V
V
SYNC_H
SYNC/MODE Positive
Going Threshold Voltage
0.95
1.3
V
V
SYNC_L
SYNC/MODE Negative
Going Threshold Voltage
0.4
0.84
V
V
ID_H
V
ID0
, V
ID1
Positive Going
Threshold Voltage
0.92
1.3
V
V
ID_L
V
ID0
, V
ID1
Negative Going
Threshold Voltage
0.4
0.83
V
I
VID
VID1, VID0 Pull Down
Current
VID1, VID0 = 3.6V
1.8
3.0
A
LM2612BL
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Electrical Characteristics
(Continued)
Specifications with standard typeface are for T
A
= T
J
= 25C, and those in bold face type apply over the full Operating Tem-
perature Range (T
A
= T
J
= -25C to +85C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 =
0V.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
f
sync
SYNC/MODE Clock
Frequency Range
(Note 8)
500
1000
kHz
F
OSC
Internal Oscillator
Frequency
LM2612ABL/ATL, PWM Mode
(SYNC = VIN)
468
600
732
kHz
LM2612BBL/BTL, PWM Mode
(SYNC = VIN)
450
600
750
T
min
Minimum ON-Time of P FET
Switch in PWM Mode
200
nS
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: Thermal shutdown will occur if the junction temperature exceeds the 150C maximum junction temperature of the device.
Note 3: Thermal resistance specified with 2 layer PCB(0.5/0.5 oz. cu).
Note 4: The LM2612 is designed for applications where turn-on after system power-up is controlled by the system processor and internal UVLO (Under Voltage
LockOut) circuitry is unnecessary. 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 exhibits safe behavior while enabled at low input voltages, this is not guaranteed.
Note 5: 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
2%.
Note 6: : 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 7: 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 s to allow the inductor current to diminish.
Note 8: SYNC driven with an external clock switching between V
IN
and GND. When an external clock is present at SYNC, the IC is forced to PWM mode at the
external clock frequency. The LM2612 synchronizes to the rising edge of the external clock.
LM2612BL
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