|
|
PDF L6928 Data sheet ( Hoja de datos )
| Número de pieza | L6928 | |
| Descripción | High efficiency monolithic synchronous step down regulator | |
| Fabricantes | ST Microelectronics | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de L6928 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
L6928
High efficiency monolithic synchronous step down regulator
General features
■ 2V to 5.5V battery input range
■ High efficiency: up to 95%
■ Internal synchronous switch
■ No external schottky required
■ Extremely low quiescent current
■ 1µA max shutdown supply current
■ 800mA max output current
■ Adjustable output voltage from 0.6V
■ Low drop-out operation: up to 100% duty cycle
■ Selectable low noise/low consumption mode at
light load
■ Power good signal
■ ±1% output voltage accuracy
■ Current-mode control
■ 1.4MHz switching frequency
■ Externally synchronizable
from 1MHz to 2MHz
■ OVP
■ Short circuit protection
Applications
■ Battery-powered equipments
■ Portable instruments
■ Cellular phones
■ PDAs and hand held terminals
■ DSC
■ GPS
Application test circuit
MSOP8
VFQFPN8
Description
The device is dc-dc monolithic regulator
specifically designed to provide extremely high
efficiency.
L6928 supply voltage can be as low as 2V
allowing its use in single Li-ion cell supplied
applications. Output voltage can be selected 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 1.4MHz fixed-frequency,
current mode-architecture.
Low Consumption Mode operation can be
selected at light load conditions, allowing
switching losses to be reduced. L6928 is
externally synchronizable with a clock which
makes it useful in noise-sensitive applications.
Other features like Powergood, Overvoltage
protection, Shortcircuit protection and Thermal
Shutdown (150°C) are also present.
October 2006
VIN=2V to 5.5V
C1
10µF
6.3V
SYNC
VCC
RUN
7
6
1
2
COMP
D01IN1528
C2
220pF
L 4.7µH
5
LX
R3
500K
8
PGOOD
3
4 VFB
GND
Rev 4
R2
200K
R1
100K
VOUT=1.8V
C4
10µF
6.3V
1/16
www.st.com
16
1 page  
L6928
3 Electrical characteristics
Table 4. Electrical characteristcs
(TJ = 25°C, VIN = 3.6V unless otherwise specified) (1)
Symbol
Parameter
Test condition
Vcc Operating input voltage
After turn on
Vcc ON Turn On threshold
Vcc OFF Turn Off threshold
Vcc hys Hysteresis
Rp High side Ron
Vcc = 3.6V, Ilx =100mA
Rn Low side Ron
Vcc = 3.6V, Ilx =100mA
Peak current limit
Ilim
Valley current limit
Vout
fosc
fsync
Output voltage range
Oscillator frequency
Sync mode clock (2)
DC characteristics
Quiescent current (low
noise mode)
Iq
Quiescent current (low
cunsumption mode)
Ish Shutdown current
Ilx LX leakage current (2)
Error amplifier characteristics
Vcc = 3.6V
Vcc = 3.6V
Vsync = 0V, no load,
VFB > 0.6V
Vsync = Vcc, no load,
VFB > 0.6V
RUN to GND, Vcc = 5.5V
RUN to GND, VLX = 5.5V,
Vcc = 5.5V
RUN to GND, VLX = 0V,
Vcc = 5.5V
Vfb Voltage feedback
Ifb Feedback input current (2) VFB = 0.6V
Electrical characteristics
Min Typ Max Unit
(1) 2
5.5 V
2.2 V
2V
100 mV
240 300
mΩ
(1) 400
215 300
mΩ
(1) 400
1 1.2 1.5
(1) 0.85
1.65
A
1
(1) 0.9
1.4 1.7
1.85
A
Vfb Vcc V
1.4 MHz
1 2 MHz
230 µA
(1) 25 50 µA
0.2 µA
1 µA
1 µA
0.593 0.600 0.607
(1) 0.590 0.600 0.610
25
V
V
nA
5/16
5 Page 
L6928
5
Additional features and protections
Additional features and protections
5.1 DROPOUT operation
The Li-Ion battery voltage ranges from approximately 3V and 4.1V-4.2V (depending on the
anode material). In case the regulated output voltage is from 2.5V and 3.3V, it can be that,
close to the end of the battery life, the battery voltage goes down to the regulated one. In
this case the device stops to switch, working at 100% of duty cycle, so minimizing the
dropout voltage and the device losses.
5.2 PGOOD (Power Good Output)
A power good output signal is available. The VFB pin is internally connected to a comparator
with a threshold set at 90% of the of reference voltage (0.6V). Since the output voltage is
connected to the VFB pin by a resistor divider, when the output voltage goes lower than the
regulated value, the VFB pin voltage goes lower than 90% of the internal reference value.
The internal comparator is triggered and the PGOOD pin is pulled down.
The pin is an open drain output and so, a pull up resistor should be connected to him.
If the feature is not required, the pin can be left floating.
5.3 Adjustable output voltage
The output voltage can be adjusted by an external resistor divider from a minimum value of
0.6V up to the input voltage. The output voltage value is given by:
Equation 4
VOUT = 0.6 ⋅
⎛
⎝
1
+
R-R----21-⎠⎞
5.4 OVP (Overvoltage Protection)
The device has an internal overvoltage protection circuit to protect the load.
If the voltage at the feedback pin goes higher than an internal threshold set 10% (typ) higher
than the reference voltage, the low side power MOSFET is turned on until the feedback
voltage goes lower than the reference one.
During the overvoltage circuit intervention, the zero crossing comparator is disabled so that
the device is also able to sink current.
5.5 Thermal shutdown
The device has also a thermal shutdown protection activated when the junction temperature
reaches 150°C. In this case both the high side MOSFET and the low side one are turned
off. Once the junction temperature goes back lower than 95°C, the device restarts the
normal operation.
11/16
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet L6928.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| L6920 | 1V HIGH EFFICIENCY SYNCRONOUS STEP UP CONVERTER |  STMicroelectronics |
| L6920D | 1V HIGH EFFICIENCY SYNCRONOUS STEP UP CONVERTER | STMicroelectronics |
| L6920DB | Synchronous rectifier step up converter | STMicroelectronics |
| L6920DC | Synchronous rectifier step up converter | STMicroelectronics |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |