L6925D
HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS
STEP DOWN REGULATOR
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2.7V TO 5.5V BATTERY INPUT RANGE
HIGH EFFICIENCY: UP TO 95%
INTERNAL SYNCHRONOUS SWITCH
NO EXTERNAL SCHOTTKY REQUIRED
EXTREMELY LOW QUIESCENT CURRENT
800mA MAX OUTPUT CURRENT
ADJUSTABLE OUTPUT VOLTAGE FROM 0.6V
LOW DROP-OUT OPERATION: UP TO100%
DUTY CYCLE
SELECTABLE LOW NOISE/LOW
CONSUMPTION MODE AT LIGHT LOAD
LOW BATTERY INPUT
LOW BATTERY OUTPUT
±1% OUTPUT VOLTAGE ACCURACY
CURRENT-MODE CONTROL
600kHz SWITCHING FREQUENCY
EXTERNALLY SYNCHRONIZABLE FROM
500kHz TO 1.4MHz
OVP
SHORT CIRCUIT PROTECTION
MSOP8
ORDERING NUMBERS:
L6925D (Tube)
L6925013TR (Tape & Reel)
DESCRIPTION
The device is dc-dc monolithic regulator specifically
designed to provide extremely high efficiency.
The device has on UVLO set at 2.7V cause it is part-
icurarly thought for single Li-ion cell applications.
Output voltage can be selected by an external divider
down to 0.6V. Duty Cycle can saturate to 100% al-
lowing low drop-out operation. The device is based
on a 600kHz fixed-frequency, current mode-architec-
ture. Low Consumption Mode operation can be se-
lected at light load conditions, allowing switching
losses to be reduced. L6925D is externally synchro-
nizable with a clock which makes it useful in noise-
sensitive applications. LBI pin can be used to have a
LBO signal when the Battery voltage is lower than a
preset value. Other features like, Overvoltage protec-
tion, Shortcircuit protection and Thermal Shutdown
(150°C) are also present.
APPLICATIONS
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BATTERY-POWERED EQUIPMENTS
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PORTABLE INSTRUMENTS
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CELLULAR PHONES
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PDAs AND HAND HELD TERMINALS
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DSC
s
GPS
APPLICATION TEST CIRCUIT
V
IN
=2.7V to 5.5V
C1
10µF
6.3V
R2
600K
R1
100K
SYNC
V
CC
LBI
7
6
1
8
COMP
L 6.8µH
5
LX
R4
200K
V
OUT
=1.8V
C4
10µF
6.3V
3
2
C2
220pF
4
GND
VFB
R3
100K
LBO
D01IN1238B
September 2003
1/5
L6925D
ABSOLUTE MAXIMUM RATINGS
Symbol
V
6
V
5
V
1
V
3
V
2
P
tot
T
j
T
stg
LX Pin
Other pins
Input voltage
Output switching voltage
Shutdown
Feedback voltage
Analog input voltage
Power dissipation at Tamb=70°C
Junction operating temperature range
Storage temperature range
Maximum Withstanding Voltage Range Test Condition: CDF-
AEC-Q100-002- “Human Body Model” Acceptance Criteria:
“Normal Performance’
Parameter
Value
-0.3 to 6
-1 to V
CC
-0.3 to V
CC
-0.3 to V
CC
-0.3 to V
CC
0.45
-40 to 150
-65 to 150
±1000
±2000
Unit
V
V
V
V
V
W
°C
°C
V
V
PIN CONNECTION
LBI
COMP
VFB
GND
1
2
3
4
D01IN1239A/mod
8
7
6
5
LBO
SYNC
V
CC
LX
THERMAL DATA
Symbol
R
th j-amb
Parameter
Thermal Resistance Junction to Ambient
Value
180
Unit
°C/W
PIN FUNCTIONS
N
1
2
3
4
5
6
7
8
Name
LBI
COMP
VFB
GND
LX
VCC
SYNC
LBO
Description
Battery low voltage detector input. The internal threshold is set to 0.6V. The external threshold
can be adjusted by using an external resistor divider.
Error amplifier output. Compensate it with a 220pF capacitor
Error amplifier input. The output voltage can be adjusted by using an external resistor divider
connected to this pin (V
FB
= 0.6V).
Ground.
Switch node connection to the inductor.
Input voltage.
This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device.
Battery low voltage detector output. If the voltage at the LBI pin drops below the internal
thrshold, LBO goes low. The LBO is an open drain output. A pull_up resistor should be
connected between the pin and the output voltage
2/5
L6925D
ELECTRICAL CHARACTERISTICS
(T
J
= 25°C, V
CC
= 3.6V unless otherwise specified)
Symbol
V
cc
V
cc ON
V
cc OFF
V
cc hys
R
p
R
n
I
lim
Parameter
Operating input voltage
Turn On threshold
Turn Off threshold
Hysteresis
High side Ron
Low side Ron
Peak current limit
Valley current limit
V
out
f
osc
f
sync
Output voltage range
Oscillator frequency
Sync mode clock (*)
500
V
cc
= 3.6V, I
lx
=100mA
V
cc
= 3.6V, I
lx
=100mA
V
cc
= 3.6V
V
cc
= 3.6V
0.6
600
1400
Test Condition
After Turn On
Min
2.7
2.8
2.65
150
240
215
1.2
1.4
Vcc
Typ
Max
5.5
Unit
V
V
V
mV
mΩ
mΩ
A
A
V
KHz
KHz
DC CHARACTERISTICS
I
q
Quiescent current
(low noise mode)
Quiescent current
(low cunsumption mode)
I
sh
I
lx
Shutdown current
LX leakage current (*)
V
sync
= 0V, no load,
V
FB
> 0.6V
V
sync
= V
cc
, no load,
V
FB
> 0.6V
V
cc
< 2.7V, V
FB
> 0.6V
V
cc
< 2.7V, V
LX
= V
cc
V
cc
< 2.7V, V
LX
= 0V
ERROR AMPLIFIER CHARACTERISTICS
V
fb
I
fb
Voltage feedback
Feedback input current (*)
V
FB
= 0.6V
0.593
0.6
25
0.607
V
nA
230
25
0.2
1
1
µA
µA
µA
µA
µA
SYNC/MODE FUNCTION
V
sync_H
V
sync_L
LB SECTION
V
LBI
V
LBO
I
LK-LBO
LBI Threshold
LBO Logic Low
LBO Leakage Current (*)
I
sink
= 1mA, V
cc
= 3.6V,
V
LBI
< 0.6V
V
LBO
= 3.6V, V
cc
= 3.6V,
V
LBI
> 0.6V
0.6
0.2
0.4
50
V
V
nA
Sync mode threshold high
Sync mode threshold low
0.5
1.3
V
V
PROTECTIONS
HOVP
Hard overvoltage threshold
10
%Vout
(*) Guaranteed by design
3/5
L6925D
mm
DIM.
MIN.
A
A1
A2
b
c
D (1)
E
E1 (1)
e
L
L1
k
aaa
Note:
inch
MAX.
1.10
MIN.
TYP.
MAX.
0.043
0.002
0.03
0.010
0.005
0.114
0.183
0.114
0.118
0.193
0.118
0.026
0.700
0.016
0.022
0.037
0˚ (min.) 6˚ (max.)
0.100
0.004
0.028
0.033
0.006
0.037
0.016
0.009
0.122
0.20
0.122
TYP.
OUTLINE AND
MECHANICAL DATA
0.050
0.750
0.250
0.130
2.900
4.650
2.900
3.000
4.900
3.000
0.650
0.400
0.550
0.950
0.850
0.150
0.950
0.400
0.230
3.100
5.150
3.100
1. D and F does not include mold flash or protrusions.
Mold flash or potrusions shall not exceed 0.15mm
(.006inch) per side.
MSOP8
(Body 3mm)
4/5
L6925D
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics.
All other names are the property of their respective owners
© 2003 STMicroelectronics - All rights reserved
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5/5
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