SGS Thomson Microelectronics L6925D Datasheet
HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS
■ 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
■
ADJUSTABL E OUTPUT VOLTAGE FROM 0.6V
■ LOW DROP-OUT OPERA TION: 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
APPLICATIONS
■ BATTERY-POWERED EQUIPMENTS
■ PORTABLE INSTRUMENTS
■ CELLULAR PHONES
■ PDAs AND HAND HELD TERMINALS
■ DSC
■ GPS
L6925D
STEP DOWN REGULATOR
MSOP8
ORDERING NUMBERS: L69 25D (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 particurarly thought for single Li-ion cell applications.
Output voltage can be selecte d by an external divider
down to 0.6V. Duty Cycle can saturate to 100% allowing low drop-out operation. The device is based
on a 600kHz fixed-fr equency, current mode -arc hitecture. Low Consumption Mode operation can be selected at light load conditions, allowing switching
losses to be reduced. L6925D is externally synchronizable with a clock which makes it useful in noisesensitive 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 protection, Shortcircuit protection and Thermal Shutdown
(150°C) are also present.
APPLICATION TEST CIRCUIT
V
=2.7V to 5.5V
IN
C1
10µF
6.3V
September 2003
SYNC
R2
600K
R1
100K
D01IN1238B
7
V
CC
6
LBI
1
8
LBO
24
COMP GND
C2
220pF
L 6.8µH
5
LX
VFB
3
R4
200K
R3
100K
=1.8V
V
OUT
C4
10µF
6.3V
1/5
L6925D
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
V
V
V
V
P
tot
T
T
stg
LX Pin Maximum Withstanding Voltage Range Test Condition: CDF-
Other pins ±2000 V
PIN CONNECTION
Input voltage -0.3 to 6 V
6
Output switching voltage -1 to V
5
Shutdown -0.3 to V
1
Feedback voltage -0.3 to V
3
Analog input voltage -0.3 to V
2
Power dissipation at Tamb=70°C0.45W
Junction operating temperature range -40 to 150 °C
j
Storage temperature range -65 to 150 °C
AEC-Q100-002- “Human Body Model” Acceptance Criteria:
“Normal Performance’
CC
CC
CC
CC
±1000 V
V
V
V
V
LBI
COMP
VFB
GND
1
2
3
4LX
D01IN1239A/mod
7
6
5
LBO8
SYNC
V
CC
THERMAL DATA
Symbol Parameter Value Unit
R
th j-amb
Thermal Resistance Junction to Ambient 180 °C/W
PIN FUNCTIONS
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
4 GND Ground.
= 0.6V).
FB
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
2/5
Battery low voltage detector output. If the voltage at the LBI pin drops below the internal
thrshold, LBO
connected between the pin and the output voltage
goes low. The LBO is an open drain output. A pull_up resistor should be
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