|
|
PDF RT9912A Data sheet ( Hoja de datos )
| Número de pieza | RT9912A | |
| Descripción | Multi-Channel Power Management IC | |
| Fabricantes | Richtek | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de RT9912A (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
|
No Preview Available !
RT9912A
Multi-Channel Power Management IC for Portable Device
General Description
The RT9912A is a multi-channel power management IC
providing power conversion and system power manage-
ment functions for one or two alkaline battery powered
portable handheld device.
The RT9912A integrates one high efficiency synchronous
buck regulator, one high efficiency boost regulator, one
linear regulator and one adjustable voltage detector for
reset function.
Ordering Information
RT9912A
Package Type
QW : WQFN-24L 4x4 (W-Type)
Note :
Lead Plating System
G : Green (Halogen Free and Pb Free)
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Features
z 300mA Sync. Step Down Converter for VCORE
z 300mA Sync. Step Up Converter for IO and Memory
z High Efficiency Up to 92%
z Low Dropout Linear Regulator
z Adjustable Voltage Detector for Reset Function
z Current Limit Protection
z Thermal Shutdown Protection
z Low Operation Current Consumption
z Small 24-Lead WQFN Package
z RoHS Compliant and Halogen Free
Applications
z DSC
z Portable Multimedia Player
z GPS
Pin Configurations
(TOP VIEW)
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
VDD1
FB1
ENSW
PSW
NC
ENBST
24 23 22 21 20 19
1 18 FB4
2 17 VDD4
3 16 RESET
GND
4 15 ENBUK
5 14 VDD3
6 25 13 FB3
7 8 9 10 11 12
WQFN-24L 4x4
DS9912A-01 April 2011
www.richtek.com
1
Free Datasheet http://www.datasheet4u.com/
1 page  
RT9912A
Absolute Maximum Ratings (Note 1)
z Supply Voltage, VDD1, VDD2, VDD3, VDD4, PVDD2 -------------------------------------------------------------------- −0.3V to 6.5V
z LX1 and LX2 Pin Switch Voltage ---------------------------------------------------------------------------------------- −0.3V to 6.5V
z Other I/O Pin Voltage ------------------------------------------------------------------------------------------------------ −0.3V to 6.5V
z Power Dissipation, PD @ TA = 25°C
WQFN-24L 4x4 ------------------------------------------------------------------------------------------------------------- 1.852W
z Package Thermal Resistance (Note 2)
WQFN-24L 4x4, θJA -------------------------------------------------------------------------------------------------------- 54°C/W
WQFN-24L 4x4, θJC ------------------------------------------------------------------------------------------------------- 7°C/W
z Junction Temperature ------------------------------------------------------------------------------------------------------ 150°C
z Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------- 260°C
z Storage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, VBAT ----------------------------------------------------------------------------------------------- 1.7V to 5V
z Junction Temperature Range --------------------------------------------------------------------------------------------- −40°C to 125°C
z Ambient Temperature Range --------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VDD1 = VDD2 = VDD3 = VDD4 = 3.3V, TA = 25°C, unless otherwise specified)
P ara meter
Sy mbol
Test Condition
Supply Voltage
Minimum Operating Input Voltage
Minimum Startup Voltage (Boost) VST
VDD1 Operating Voltage
VDD1
VDD2 Operating Voltage
VDD3 Operating Voltage
VDD2
VDD3
VDD4 Operating Voltage
VDD1 Over Voltage Protection
VDD4
RL = 3kΩ
RL = 3kΩ
VDD2, PVDD2 Pin Voltage
Supply Current
Shutdown Supply Current
Boost Supply Current
IOFF
IVDD1
VENBST = VENSW = 0V
VDD4 = 0V = VDD3
VDD1 = 3.3V, VFB1 = 0.9V
VENBST = VENSW = 3.3V
VOUT1 = 3.3V
VDD2 = VDD3 = VDD4 = 0V
(no switching)
Buck Supply Current
IVDD2
VDD2 = 3.3V, VFB2 = 0.9V
VENBST = VENSW = 0V
VDD1 = VDD3 = VDD4 = 0V
(no switching)
DS9912A-01 April 2011
Min Typ Max Units
-- -- 1.7 V
-- 0.8 1.1 V
1.7 -- 5 V
1.7 -- 5 V
2.5 -- 5 V
1.5 -- 5 V
5.1 6 6.5 V
-- -- 10 uA
-- 45 70 uA
-- 85 140 uA
To be continued
www.richtek.com
5
Free Datasheet http://www.datasheet4u.com/
5 Page 
RT9912A
The maximum output voltage for LDO depends on the
voltage drop cross the internal P-MOSFET. Normally, the
value is (VDD3 − 0.4V) as 200mA loading. The minimum
output voltage is 1.6V, which is decided by the working
range of the internal circuit.
Output Voltage Setting
The regulated output voltage can be calculated following
formula :
VOUT
=
VFB
× ⎛⎜⎝1+
R1 ⎞
R2 ⎟⎠
To place the resistor-divider as close as possible to chip
can reduce noise sensitivity.
Voltage Detector
The RT9912A integrates a voltage detector with push-pull
output. The voltage detector senses VDD3V3_IO through
a resistor divider and compares it with internal 0.3V
reference voltage. When the sensed voltage is lower than
the reference voltage, the RESET pin output logic low
signal for system access. Connecting a capacitor from
the CT pin to GND can set the detect delay time according
to Figure 1.
CH4 Detecter Delay Time
120
100
80
60
40
20
0
0 10 20 30 40 50 60 70 80 90 100
Capacitance (nF)
Figure 1. Detector Delay Time
Inductor Selection
To select suitable inductance value is very important for
optimal performance. For boost converter, the control
method is constant on time and minimum off time. If the
inductance is low, it will cause effects of high in ductor
current and high output voltage ripple. The inductance value
can be calculated by following formula.
LMIN
≥
VIN(MAX) × TON
VLIM(MIN)
Where LMIN = minimum inductance
VIN(MAX) = maximum input voltage
TON = 0.75us
ILIM(MIN) = 0.8A
A 4.7uH inductor is recommended for typical application.
For buck converter, a 4.7uH inductor is recommended
when VIN is less than 2.6V.
In addition, make sure the inductor saturation current
rating should be greater than the inductor peak current.
Input Capacitor Selection
For better input bypassing, low-ESR ceramic capacitor is
recommended for better performance. A 10uF input
capacitor is sufficient and it is flexible to reduce the value
for a lower output power requirement.
Output Capacitor Selection
For lower output voltage ripple, low-ESR ceramic capacitor
is recommended. The output voltage ripple consists of
two components : one is the pulsating output ripple current
flowing through the ESR, and the other is the capacitive
ripple caused by charging and discharging.
For ceramic capacitor, the voltage ripple value is
approximated by :
VRIPPLE ≅ VRIPPLE_C
For boost converter, calculate the minimum output
capacitance as the following formula :
COUT ≥
L × 0.5IPEAK2
VREPPLE_C
DS9912A-01 April 2011
www.richtek.com
11
Free Datasheet http://www.datasheet4u.com/
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet RT9912A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| RT9912A | Multi-Channel Power Management IC | Richtek |
| 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 |