R1285L series
2ch DCDC for OLED
NO.EA-209-090703
OUTLINE
The R1285L 2ch DC/DC converter is designed for OLED Display power source. It contains a step up DC/DC
converter and an inverting DC/DC converter to generate two required voltages by OLED Display.
Step up DC/DC converter generates boosted output voltage to 4.6V ~ 5.0V. Inverting DC/DC converter generates
negative voltage –2.0V ~ -6.0V independently. Each of the R1285 series consists of an oscillator, a PWM control
circuit, a voltage reference, error amplifiers, over current protection circuits, short protection circuits, an under
voltage lockout circuit (UVLO), a complete shutdown switch and an Nch driver for boost operation, a Pch driver for
inverting, and so on. A high efficiency boost and inverting DC/DC converter can be composed with external
inductors, diodes, capacitors and resistors. Start up sequence is internally made.
FEATURES
Operating Voltage • • • • • 2.3V ~ 4.8V
Step Up DC/DC (CH1)
Internal Pch MOSFET for complete shutdown (Ron=300mΩTyp.)
Internal Nch MOSFET Driver (Ron=300mΩTyp.)
Output Voltage (V
OUTP
) • • • • • 4.6V ~ 5.0V (0.2VStep)
Auto Discharge function for positive output
Internal Soft start function (Typ. 4.5ms)
Over Current Protection
Maximum Duty Cycle: 85%(Typ.)
Inverting DC/DC (CH2)
Internal Pch MOSFET Driver (Ron=600mΩ Typ.)
Output Voltage (V
OUTN
) • • • • • -2V ~ -6V (0.1VStep)
Adjustable Vout Up to -6V with external resistors
Auto Discharge function for negative output
Internal Soft start function (Typ. 4.5ms)
Over Current Protection
Maximum Duty Cycle: 90%(Typ.)
[ R1285LxxxA ]
[ R1285L00xB ]
Control
Short Protection with timer latch function (Typ. 50ms)
Short condition for either or both two outputs makes all output drivers off and latches. If the
maximum duty cycle continues for a certain time, these output drivers will be turned off. This
function prevents irregular current from overheating the R1285 .
CE with start up sequence function ( CH1→CH2 )
UVLO function.
Operating Frequency • • • • • 1400kHz
Small package • • • • • DFN12 ( 2.7mm x 3.0mm )
APPLICATION
Fixed voltage power supply for portable equipment
Fixed voltage power supply for OLED
V 1.4
1
R1285L
SELECTION GUIDE
The mask option for the ICs can be selected at the user's request. The selection can be made with designating the
part number as shown below.
R1285L XX X X
←Part
Number
a
code
a
b c
b
c
contents
Setting inverting output voltage (V
OUTN
)
Stepwise setting with a step of 0.1V in the range of -2.0V to -6.0V is possible for
fixed output version (R1285LXXXA)
"00" is for Output Voltage Adjustable version (R1285L00XB)
Setting positive output voltage (V
OUTP
)
1: 4.6V
2: 4.8V
3: 5.0V
Designation of method of setting V
OUTN
A: Fixed output version
B: Adjustable version
PIN CONFIGURATION
●
DFN -2730-12
1
2
3
4
5
6
Top View
12
11
10
9
8
7
12
11
10
9
8
7
Bottom View
1
2
3
4
5
6
3
R1285L
PIN DESCRIPTIONS
●R1285LxxxA
PIN No.
1
2
3
4
5
6
7
8
9
10
11
12
NAME
PGND
V
OUTP
PV
CC
V
CC
GND
CE
TST2
TST1
V
OUTN
L
XN
L
XP
1
L
XP
2
FUNCTION
Power GND pin
Output Voltage feedback pin for Step up DC/DC
Power input pin
Analog power source input pin
Analog GND pin
Chip enable pin
TEST pin
TEST pin
Output Voltage feedback pin for Inverting DC/DC
Switching pin for Inverting DC/DC
Shutdown switch output pin
Switching pin for Step up DC/DC
●R1285L00xB
PIN No.
1
2
3
4
5
6
7
8
9
10
11
12
NAME
PGND
V
OUTP
PV
CC
V
CC
GND
CE
V
REF
V
FBN
V
OUTN
L
XN
L
XP
1
L
XP
2
FUNCTION
Power GND pin
Output Voltage feedback pin for Step up DC/DC
Power input pin
Analog power source input pin
Analog GND pin
Chip enable pin
Reference voltage output pin for Inverting DC/DC
Feedback pin for Inverting DC/DC
Output Voltage feedback pin for Inverting DC/DC
Switching pin for Inverting DC/DC
Shutdown switch output pin
Switching pin for Step up DC/DC
4
R1285L
ABSOLUTE MAXIMUM RATINGS
Item
V
CC
/ PV
CC
pin Voltage
V
OUTP
pin Voltage
CE pin Voltage
L
XP
1 pin Voltage
L
XP
2 pin Voltage
L
XN
pin Voltage
V
OUTN
pin Voltage
TST1/TST2 pin Voltage [R1285LxxxA]
V
FBN
pin Voltage [R1285L00xB]
V
REF
pin Voltage [R1285L00xB]
Power Dissipation
*1
Symbol
V
CC
V
OUTP
V
CE
V
LXP
1
V
LXP
2
V
LXN
V
OUTN
V
TST
V
FBN
V
REF
PD
Ta
Tstg
Rating
6.0
-0.3 ~ 6.0
-0.3 ~ V
CC
+0.3
-0.3 ~ V
CC
+0.3
-0.3 ~ 6.0
V
CC
-14 ~ V
CC
+0.3
V
CC
-14 ~ V
CC
+0.3
-0.3 ~ V
CC
+0.3
-0.7 ~ V
CC
+0.3
-0.7 ~ V
CC
+0.3
1000
-40 ~ +85
-55 ~ +125
*2
*2
(GND / PGND=0V)
Unit
V
V
V
V
V
V
V
V
V
V
mW
ºC
ºC
Operating Temperature Range
Storage Temperature Range
∗1)
For Power Dissipation, please refer to PACKAGE INFORMATION to be described.
∗2)In
case the voltage range is from –0.7V to –0.3V, permissible current is 10mA or less.
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded ever for an
instant under any conditions. Moreover, such values for any two items must not be reached
simultaneously. Operation above these absolute maximum ratings may cause degradation or
permanent damage to the device. These are stress ratings only and do not necessarily imply
functional operation these limits.
5
MCU
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