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PDF RT9287 Data sheet ( Hoja de datos )
| Número de pieza | RT9287 | |
| Descripción | Boost Converter | |
| Fabricantes | Richtek Technology | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de RT9287 (archivo pdf) en la parte inferior de esta página. Total 13 Páginas | ||
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Preliminary
RT9287
Boost Converter for OLED Power with Dual LDO
General Description
The RT9287 integrates a boost converter for OLED power
and a Dual LDO for camera image sensor power. To achieve
high efficiency, the boost converter optimizes its operating
frequency for small LC filters value and reduces the
operating current. Moreover, the internal soft-start function
reduces the inrush current.
For the Dual LDO part, it possesses functions of 2%
accuracy, dual channel, low dropout voltage
(240mV@300mA), low noise, low ground current and
low dropout regulator sourcing up to 300mA at each
channel. For battery-powered devices, it provides near
zero shutdown current. Moreover, it also integrates
functions such as current limiting, over temperature, output
short circuit, 27μA low ground current per LDO and
short circuit thermal folded back protection. When output
short circuit occurs, the RT9287 reduces its over
temperature protection trip point to provide maximum
safety to users. The RT9287 is available in WDFN-10L
3x3 package.
Ordering Information
RT9287-
Package Type
QW : WDFN-10L 3x3 (W-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
LDO Output Voltage : VOUT1/VOUT2
MG : 2.80V/1.80V
Note :
Richtek Pb-free and Green 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.
`100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area, otherwise visit our website for detail.
DS9w28w7-w01.DAautgauSsthe20e0t47 U.com
Features
z Boost Converter
`VIN Operating Range : 2.7V to 5.5V
`Maximum Output Voltage Up to 20V
`Output Current up to 100mA at VOUT = 12V.
`Low Shutdown Supply Current
`Minimize the External Component
`Small LC Filter
`Internal Soft Start
z Dual LDO
`Wide Operating Voltage Ranges : 2.7V to 5.5V
`Low-Noise for RF Application
`No Noise Bypass Capacitor Required
`Fast Response in Line/Load Transient
`TTL-Logic-Controlled Shutdown Input
`Low Temperature Coefficient
`Dual LDO Outputs (300mA/300mA)
`Ultra-low Quiescent Current 27μA/LDO
`High Output Accuracy 2%
`Short Circuit Protection
`Thermal Shutdown Protection
`Current Limit Protection
`Short Circuit Thermal Folded Back Protection
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Camera Phone
z OLED Power
Pin Configurations
(TOP VIEW)
VDD1 1
EN1 2
EN2 3
ENB 4
FB 5
GND
11
10 VLDO1
9 VLDO2
8 GND
7 VDD2
LX
WDFN-10L 3x3
www.richtek.com
1
1 page  
Preliminary
RT9287
Par amete r
Sy mbol
Test Condition
Min Typ Max Units
Dual LDO
Input Voltage
Dropout Voltage (Note 5)
Output Voltage Range
VLDO1,2 Accuracy
Line Regulation
Load Regulation
Current Limit
Quiescent Current
Shutdown Current
EN1,2 Threshold
Output Voltage TC
V DD 1
VDD = 2.7V to 5.5V
2.7 -- 5.5
V DR OP
IOUT = 150mA
IOUT = 300mA
-- 120 --
-- 240 --
V LDO1,
V LDO2
1.2 -- 3.6
ΔV IOUT = 1mA
−2 -- +2
ΔVLINE
VDD1 = (VLDO1,2 + 0.3V) to 5.5V
or VDD1 > 2.7V, whichever is
larger
--
-- 0.2
V
mV
mV
V
%
%
ΔVLOAD 1mA < IOUT < 300mA
-- -- 0.6 %
RLOAD = 1Ω
330 450 700
mA
IQ VEN1, 2 > 1.5V
-- 58 80 μA
ISHDN
VEN1, 2 < 0.4V
-- -- 1 μA
V IH
VDD = 2.7V to 5.5V, Power On
1.5 --
--
V
VIL VDD = 2.7V to 5.5V, Shutdown -- -- 0.4 V
-- 100 -- ppm/°C
Thermal Shutdown
Thermal Shutdown Hysteresis
Thermal Shutdown Hysteresis
TSD
ΔTSD
ΔTSD
PSRR ILOAD = 10mA
PSRR ILOAD = 150mA
PSRR
f = 100Hz
f = 1kHz
f = 10kHz
f = 100Hz
f = 1kHz
f = 10kHz
-- 165
-- 40
-- 40
-- 65
-- 60
-- 50
-- 65
-- 50
-- 50
--
--
--
--
--
--
--
--
--
°C
°C
°C
dB
dB
dB
dB
dB
dB
Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2. Devices are ESD sensitive. Handling precaution recommended.
Note 3. The device is not guaranteed to function outside its operating conditions.
Note 4. θJA is measured in the natural convection at TA = 25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard. The case point of θJC is on the expose pad for the WDFN package.
Note 5. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
DS9287-01 August 2007
www.richtek.com
5
5 Page 
Preliminary
RT9287
Table 1. Suggested Resistance for Output Voltage
Control
Conditions
Case A :
Normal Voltage = 16V
(GPIO = 0V)
Dimming Voltage = 12V
(GPIO = 1.8V)
Case B :
Normal Voltage = 16V
(GPIO = 0V)
Dimming Voltage = 12V
(GPIO = 2.8V)
RA
(kΩ)
RB RGPIO
(kΩ) (kΩ)
990 102 445
990 94 690
L1 D1
4.7uH to 22uH SS0520
VOUT
+
VIN
2.7V to 5.5V
C1
1uF
RT9287
7 VDD2 LX 6
VENB>1.5V 4 ENB
VENB<0.4V
8 GND
FB 5
GPIO
C2
RA OLED
RGPIO
RB
Figure 3. Application Circuit for 2-level Output Voltage
Control
Dual LDO
Like any low-dropout regulator, the external capacitors used
with the RT9287 must be carefully selected for regulator
stability and performance. Using a capacitor whose value
is > 1μF on the LDO input and the amount of capacitance
can be increased without limit. The input capacitor must
be located a distance of not more than 0.5 inch from the
input pin of the IC and returned to a clean analog ground.
Any high quality ceramic or tantalum capacitor can be
used for this part. The capacitor with larger value and lower
ESR (equivalent series resistance) provides better PSRR
and line-transient response.
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all
applications. The LDO is designed specifically to work
with low ESR ceramic output capacitor in space-saving
and performance consideration. Using a ceramic capacitor
whose value is at least 1μF with ESR is > 20mΩ on the
LDO output ensures stability. The LDO still works well
with other kinds of output capacitor due to the wide stable
ESR range. Figure 4 shows the curves of allowable ESR
range as a function of load current for various output
DS9287-01 August 2007
capacitor values. Output capacitor of larger capacitance
can reduce noise and improve load transient response,
stability, and PSRR. The output capacitor should be located
not more than 0.5 inch from the VOUT pin of the LDO and
returned to a clean analog ground.
Region of Stable COUT ESR vs. Load Current
100
VIN = 5V, CIN = COUT1 = COUT2 = 1uF/X7R
10
Unstable Range
1
0.1 Stable Range
0.01
Simulation Verify
0.001
0
50 100 150 200 250
Load Current (mA)
Figure 4. Stable Cout ESR Range
300
Thermal protection limits power dissipation in LDO. When
the operating junction temperature exceeds a certain
temperature, the OTP circuit starts the thermal shutdown
function and turns the pass element off. The pass element
turns on again after the junction temperature is cooled
down. The RT9287 lowers its OTP trip level from 170°C to
110°C when output short circuit occurs (VOUT < 0.4V) as
shown in Figure 5. It reduces operating junction
temperature and provides maximum safety to customer
while output short circuit occurring.
VOUT Short to GND
VOUT
IOUT
0.4V
TSD
OTP Trip
170 °C
Point
110 °C
110 °C
IC Temperature
80 °C
Figure 5. Short Circuit Thermal Folded Back Protection
when Output Short Circuit Occurs (Patent)
www.richtek.com
11
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet RT9287.PDF ] | |
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