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L6925D
September 2003
s
2.7V TO 5.5V BATTERY INPUT RANGE
s
HIGH EFFICIENCY: UP TO 95%
s
INTERNAL SYNCHRONOUS SWITCH
s
NO EXTERNAL SCHOTTKY REQUIRED
s
EXTREMELY LOW QUIESCENT CURRENT
s
800mA MAX OUTPUT CURRENT
s
ADJUSTABLE OUTPUT VOLTAGE FROM 0.6V
s
LOW DROP-OUT OPERATION: UP TO100%
DUTY CYCLE
s
SELECTABLE LOW NOISE/LOW
CONSUMPTION MODE AT LIGHT LOAD
s
LOW BATTERY INPUT
s
LOW BATTERY OUTPUT
s
1% OUTPUT VOLTAGE ACCURACY
s
CURRENT-MODE CONTROL
s
600kHz SWITCHING FREQUENCY
s
EXTERNALLY SYNCHRONIZABLE FROM
500kHz TO 1.4MHz
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OVP
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SHORT CIRCUIT PROTECTION
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
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
(150C) are also present.
MSOP8
ORDERING NUMBERS: L6925D (Tube)
L6925013TR (Tape & Reel)
HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS
STEP DOWN REGULATOR
APPLICATION TEST CIRCUIT
L 6.8
H
SYNC
LX
VFB
C1
10
F
6.3V
C2
220pF
C4
10
F
6.3V
R4
200K
R2
600K
R1
100K
R3
100K
V
IN
=2.7V to 5.5V
V
OUT
=1.8V
V
CC
LBI
COMP
GND
LBO
D01IN1238B
7
6
1
8
3
5
2
4
L6925D
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ABSOLUTE MAXIMUM RATINGS
PIN CONNECTION
THERMAL DATA
PIN FUNCTIONS
Symbol
Parameter
Value
Unit
V
6
Input voltage
-0.3 to 6
V
V
5
Output switching voltage
-1 to V
CC
V
V
1
Shutdown
-0.3 to V
CC
V
V
3
Feedback voltage
-0.3 to V
CC
V
V
2
Analog input voltage
-0.3 to V
CC
V
P
tot
Power dissipation at Tamb=70
C
0.45
W
T
j
Junction operating temperature range
-40 to 150
C
T
stg
Storage temperature range
-65 to 150
C
LX Pin
Maximum Withstanding Voltage Range Test Condition: CDF-
AEC-Q100-002- "Human Body Model" Acceptance Criteria:
"Normal Performance'
1000
V
Other pins
2000
V
Symbol
Parameter
Value
Unit
R
th j-amb
Thermal Resistance Junction to Ambient
180
C/W
N
Name
Description
1
LBI
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.
2
COMP
Error amplifier output. Compensate it with a 220pF capacitor
3
VFB
Error amplifier input. The output voltage can be adjusted by using an external resistor divider
connected to this pin (V
FB
= 0.6V).
4
GND
Ground.
5
LX
Switch node connection to the inductor.
6
VCC
Input voltage.
7
SYNC
This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device.
8
LBO
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
LBI
COMP
VFB
GND
1
3
2
4
LX
V
CC
SYNC
LBO
8
7
6
5
D01IN1239A/mod
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L6925D
ELECTRICAL CHARACTERISTICS (T
J
= 25C, V
CC
= 3.6V unless otherwise specified)
(*) Guaranteed by design
Symbol
Parameter
Test Condition
Min
Typ
Max
Unit
V
cc
Operating input voltage
After Turn On
2.7
5.5
V
V
cc ON
Turn On threshold
2.8
V
V
cc OFF
Turn Off threshold
2.65
V
V
cc hys
Hysteresis
150
mV
R
p
High side Ron
V
cc
= 3.6V, I
lx
=100mA
240
m
R
n
Low side Ron
V
cc
= 3.6V, I
lx
=100mA
215
m
I
lim
Peak current limit
V
cc
= 3.6V
1.2
A
Valley current limit
V
cc
= 3.6V
1.4
A
V
out
Output voltage range
0.6
Vcc
V
f
osc
Oscillator frequency
600
KHz
f
sync
Sync mode clock (*)
500
1400
KHz
DC CHARACTERISTICS
I
q
Quiescent current
(low noise mode)
V
sync
= 0V, no load,
V
FB
> 0.6V
230
A
Quiescent current
(low cunsumption mode)
V
sync
= V
cc
, no load,
V
FB
> 0.6V
25
A
I
sh
Shutdown current
V
cc
< 2.7V, V
FB
> 0.6V
0.2
A
I
lx
LX leakage current (*)
V
cc
< 2.7V, V
LX
= V
cc
1
A
V
cc
< 2.7V, V
LX
= 0V
1
A
ERROR AMPLIFIER CHARACTERISTICS
V
fb
Voltage feedback
0.593
0.6
0.607
V
I
fb
Feedback input current (*)
V
FB
= 0.6V
25
nA
SYNC/MODE FUNCTION
V
sync_H
Sync mode threshold high
1.3
V
V
sync_L
Sync mode threshold low
0.5
V
LB SECTION
V
LBI
LBI Threshold
0.6
V
V
LBO
LBO Logic Low
I
sink
= 1mA, V
cc
= 3.6V,
V
LBI
< 0.6V
0.2
0.4
V
I
LK-LBO
LBO Leakage Current (*)
V
LBO
= 3.6V, V
cc
= 3.6V,
V
LBI
> 0.6V
50
nA
PROTECTIONS
HOVP
Hard overvoltage threshold
10
%Vout
L6925D
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OUTLINE AND
MECHANICAL DATA
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
1.10
0.043
A1
0.050
0.150
0.002
0.006
A2
0.750
0.850
0.950
0.03
0.033
0.037
b
0.250
0.400
0.010
0.016
c
0.130
0.230
0.005
0.009
D (1)
2.900
3.000
3.100
0.114
0.118
0.122
E
4.650
4.900
5.150
0.183
0.193
0.20
E1 (1)
2.900
3.000
3.100
0.114
0.118
0.122
e
0.650
0.026
L
0.400
0.550
0.700
0.016
0.022
0.028
L1
0.950
0.037
k
0 (min.) 6 (max.)
aaa
0.100
0.004
Note:
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)
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.
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All other names are the property of their respective owners
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L6925D
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