Catalyst CAT3606 6-channel low noise charge pump white led driver Datasheet

CAT3606
6-Channel Low Noise Charge Pump White LED Driver
FEATURES
■
■
Drives up to 4 main LEDs and 2 sub LEDs
■
Separate control for main and sub LEDs
White LED detect circuitry on all channels
■ Shutdown current less than 1µA
■
Compatible with supply voltage of 3V to 5.5V
■
■
Power efficiency up to 90%
Small ceramic capacitors
■ Soft start and current limiting
■ Short circuit protection
■ 16-lead thin QFN package, 0.8mm
max height
■
Output current up to 30mA per LED
■ High-frequency Operation at 1MHz
■ 2 modes of operation 1x and 1.5x
APPLICATIONS
■
Cell phone main and sub-display backlight
■
Navigation
■
PDAs
■ Digital Cameras
DESCRIPTION
(1MHz) provides low noise and allows the use of
very small value ceramic capacitors.
The CAT3606 controls up to four LEDs for the main
display and two LEDs for the sub-display in cellular
phones. The device is capable of operating in either
1x (LDO) mode or 1.5x charge pump mode. All LED
pin currents are regulated and tightly matched to
achieve uniformity of brightness across the LCD
backlight. An external resistor (RSET) sets the
nominal output current.
A “zero” quiescent current mode can be achieved
via the chip enable pin EN. The Main and Sub LEDs
each have their own dedicated ON/OFF control
pins (ENM, ENS). Dimming can be achieved using
either a DC voltage to control the RSET pin current,
or by applying a PWM signal on the ENM and ENS
pins.
The device can deliver as much as 20mA per
channel during low voltage operation (3V), and
30mA per channel during nominal operation (3.3V).
A constant high-frequency switching scheme
The device is available in a 16-lead thin QFN
package with a max height of 0.8mm.
TYPICAL APPLICATION CIRCUIT
C1+
C1- C2+
Li-Ion
Battery
C2-
Main Display
Sub Display
VOUT
VIN
COUT
+
CIN
-
CAT3606
ON/OFF
EN
ENABLE
LED1-4
ENM
ENABLE
LED5-6
ENS
LED1
LED2
LED3
20mA
LED4
LED5
RSET
RSET
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
LED6
GND
1
Doc. No. 5009, Rev. B
CAT3606
ORDERING INFORMATION
Part Number
Package
Quantity per Reel
Package Marking
CAT3606HS4
Thin QFN-16 4x4mm
2000
C366
CAT3606HV4
Thin QFN-16 4x4mm
Lead Free
2000
G366
PIN CONFIGURATION
Top View
LED5 LED4 LED3 LED2
16
15
14
13
LED6
1
12 LED1
EN
2
11 C2+
ENM
3
10 C2-
ENS
4
9 C1-
GND PAD
5
6
RSET VOUT
7
8
VIN
C1+
16-lead Thin QFN (4mm x 4mm)
Note: The "exposed pad" under the package must be connected to the ground plane on the PCB.
PIN DESCRIPTIONS
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PAD
Doc. No. 5009, Rev. B
Name
LED6
EN
ENM
ENS
RSET
VOUT
VIN
C1+
C1C2C2+
LED1
LED2
LED3
LED4
LED5
GND
Function
LED6 cathode terminal
Enable/shutdown input, active high
Enable "main" input for LED1 to LED4, active low
Enable "sub" input for LED5 and LED6, active low
The LED output current is set by the current sourced out of the RSET pin
Charge pump output connected to the LED anodes
Supply voltage
Bucket capacitor 1 terminal
Bucket capacitor 1 terminal
Bucket capacitor 2 terminal
Bucket capacitor 2 terminal
LED 1 cathode terminal
LED 2 cathode terminal
LED 3 cathode terminal
LED 4 cathode terminal
LED 5 cathode terminal
Ground reference
2
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3606
ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, VOUT, LEDx voltage
Rating
-0.3 to 7.0
Unit
V
EN, ENM, ENS voltage
-0.3 to VIN
V
RSET voltage
RSET current
Ambient Temperature Range
Storage Temperature Range
Lead Temperature
ESD Ratings
Human Body Model (HBM)
Machine Model (MM) (note 1)
-0.3 to VIN
+1
-40 to +85
-65 to +160
300
V
mA
o
C
o
C
o
C
2000
200
V
V
Note 1:
Machine model is with 200pF capacitor discharged directly into each pin.
RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
Input/Output/Bucket Capacitors
ILED per LED pin
IOUT Total Output Current
Rating
3.0 to 5.5
-40 to +85
1 +20% typical
0 to 30
0 to 150
Unit
V
o
C
µF
mA
mA
ELECTRICAL OPERATING CHARACTERISTICS
Limits over recommended operating conditions unless specified otherwise. Typical values at TA = 25˚C, VIN = 3.5V,
IRSET = 5µA.
Symbol
Parameter
Conditions
IQ
Quiescent Current
VEN = 0V
1x Mode, No Load
1.5x Mode, No Load
VRSET
RSET Regulated Voltage
ILED
Programmed LED Current
ILED
LED Current Range with 6 LEDs
ILED
LED Current Range with 4 LEDs
ILED-ACC
LED Current Accuracy
ILED-DEV
Min
Typ
Max
Unit
1.17
0.1
0.3
2.6
1.2
1
1
5
1.23
µA
mA
mA
V
30
20
30
mA
mA
mA
mA
mA
mA
%
%
IRSET = 5µA
IRSET = 37µA
IRSET = 78µA
3.3 ≤ VIN ≤ 4.5 V
3.0 ≤ VIN ≤ 4.5 V
3.0 ≤ VIN ≤ 4.5V
0.5mA ≤ ILED ≤ 3mA
3mA ≤ ILED ≤ 30mA
2.4
15.0
30.0
LED Channel Matching
(ILED - ILEDAVG) / ILEDAVG
+3
1x Mode
1.5x Mode, IOUT = 100mA
0.8
1.4
6.5
1.0
2.5
10
1.3
MHz
TDROPOUT
Output Resistance
(Open Loop)
Charge Pump Frequency
1x to 1.5x Mode Transition
Dropout Delay
0.4
0.6
0.9
ms
IEN-CTR
Input Leakage Current
On Inputs EN, ENM, ENS
1
µA
On Inputs EN, ENM, ENS
ISC
High Detect Threshold
Low Detect Threshold
Input Current Limit
ILIM
Maximum Input Current
ROUT
fOSC
VEN-CTR
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
+15
+5
%
Ω
Ω
VOUT = GND
0.8
0.7
45
1.3
0.4
30
60
V
V
mA
VOUT > 1V
200
400
600
mA
3
Doc. No. 5009, Rev. B
CAT3606
BLOCK DIAGRAM
C1-
3≤VIN≤4.2V
VIN
+
CIN
Battery
C1+ C2-
C2+
1x mode (LDO)
1.5x Charge Pump
VOUT
COUT
-
Mode Control
1MHz
Oscillator
EN
LED1
LED2
LED3
LED4
1.2V
Reference
RSET
Current
Setting
20mA
LED5
LED6
Main
Sub
6 Current
Sink Regulators
ENM
ENS
LED Output
Selection
GND
Figure 1: CAT3606 Functional Block Diagram
BASIC OPERATION
LED CURRENT SETTING
At power-up, the CAT3606 starts operation in 1x
mode. If it is able to drive the programmed LED
current, it continues in 1x mode. If the battery
voltage drops to a level where the LED current
cannot be met, the driver automatically switches
into 1.5x mode, to boost the output voltage high
enough to achieve the nominal LED current.
The LED current is set by the external resistor RSET
connected between the RSET pin and ground.
Table 1 lists various LED currents and the associated RSET resistor value for standard 1% precision
surface mount resistors.
The above sequence is reinitialized each and every
time the chip is powered up or is taken out of
shutdown mode (via EN pin). The use of the Main
and Sub display enable pins (ENM or ENS) does
not affect the mode of operation.
LED Current (mA)
RSET (kΩ)
1
649
2
287
5
102
10
49.9
15
32.4
20
23.7
30
15.4
Table 1. RSET Resistor Selection
Doc. No. 5009, Rev. B
4
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3606
The enable lines ENM and ENS allow to turn On or
Off a group of LEDs as shown in Table 2.
Control Lines
EN
ENM
ENS
0
1
1
1
1
X
1
0
1
0
X
1
1
0
0
The unused LED channels can also be turned off
by connecting the respective LED pins to VOUT. In
which case, the corresponding LED driver is
disabled and the typical LED sink current is only
about 0.2mA. When the following equation is true
on any channel, the driver turns off the LED channel:
LED Outputs
Sub
Main
LED1 - LED4
LED5 - LED6
ON
ON
ON
ON
VOUT - VLED ≤ 1V (LED channel OFF)
Note: The CAT3606 is designed to drive LEDs with
forward voltage greater than 1V and is not
compatible with resistive loads.
Table 2: LED Selection
Notes: 1 = logic high (or VIN)
0 = logic low (or GND)
- = LED output OFF
X = don't care
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. 5009, Rev. B
CAT3606
TYPICAL CHARACTERISTICS
VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless
otherwise specified.
Efficiency vs. Input Voltage (6 LEDs)
Efficiency vs. Total LED Current (6 LEDs)
100
90
EFFICIENCY [%]
EFFICIENCY [%]
100
1x mode
80
1.5x mode
70
60
50
20mA per LED
90
VIN = 4V (1x mode)
80
70
60
VIN = 3.2V (1.5x mode)
50
15mA per LED
40
40
4.2
4.0
3.8
3.6
3.4
3.2
3.0
0
50
LED Current Change vs. Input Voltage
LED CURRENT CHANGE [%]
LED CURRENT CHANGE [%]
1.0
6 LEDs at 15mA
0.5
0.0
-0.5
-1.0
-1.5
3.4
3.6
3.8
4.0
4
3
6 LEDs at 15mA
Vin = 4V
2
1
0
-1
-2
-3
-4
-50
4.2
-25
INPUT VOLTAGE [V]
0
25
50
75
100
125
TEMPERATURE [°C]
Ground Current vs. Input Voltage (1x mode)
Ground Current vs. Temperature (1x mode)
0.5
0.5
GROUND CURRENT [mA]
GROUND CURRENT [mA]
200
LED Current Change vs. Temperature
1.5
3.2
150
TOTAL LED CURRENT [mA]
INPUT VOLTAGE [V]
3.0
100
0.4
0.3
0.2
6 LEDs OFF
0.1
0.0
3.0
3.2
3.4
3.6
3.8
4.0
0.3
0.2
6 LEDs OFF
Rset = 500kΩ
0.1
0.0
4.2
-40
INPUT VOLTAGE [V]
Doc. No. 5009, Rev. B
0.4
-20
0
20
40
60
80
100
TEMPERATURE [°C]
6
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3606
TYPICAL CHARACTERISTICS
VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless
otherwise specified.
Supply Current vs. Input Voltage
5.0
SUPPLY CURRENT [mA]
GROUND CURRENT [mA]
Ground Current vs. Input Voltage (1.5x mode)
4.0
3.0
2.0
VIN = 3.6V
all LEDs open
1.0
3.2
3.4
3.6
3.8
1.5x mode
120
100
1x mode
6 LEDs at 15mA
80
3.0
0.0
3.0
140
4.0
4.2
3.2
Oscillator Frequency vs. Input Voltage
3.8
4.0
4.2
Oscillator Frequency vs. Temperature
1.10
CLOCK FREQUENCY [MHz]
1.10
CLOCK FREQUENCY [MHz]
3.6
INPUT VOLTAGE [V]
INPUT VOLTAGE [V]
1.05
1.00
6 LEDs at 20mA
0.95
0.90
3.0
3.2
3.4
3.6
3.8
4.0
1.05
1.00
0.95
VIN = 3.6V
6 LEDs at 15mA
0.90
4.2
-40
-20
INPUT VOLTAGE [V]
Output Resistance vs. Input Voltage (1x mode)
100
10
OUTPUT RESISTANCE [Ω]
3
100mA load
100mA
load
2
1
0
3.0
0
20 40 60 80
TEMPERATURE [°C]
Output Resistance vs. Input Voltage (1.5x mode)
4
OUTPUT RESISTANCE [Ω]
3.4
3.2
3.4
3.6
3.8
4.0
6
100mA load
100mA
load
4
2
3.0
4.2
INPUT VOLTAGE [V]
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
8
3.2
3.4
3.6
3.8
4.0
4.2
INPUT VOLTAGE [V]
7
Doc. No. 5009, Rev. B
CAT3606
TYPICAL CHARACTERISTICS
VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless
otherwise specified.
Switching Waveforms in 1.5x Mode
Operating Waveforms in 1x Mode
Power Up 6 LEDs at 15mA, VIN = 3V (1.5x Mode)
Power Up 6 LEDs at 15mA, VIN = 3.6V (1x Mode)
LED Current vs. RSET
Line Transient Response in 1x Mode
LED CURRENT [mA]
100.0
10.0
1.0
0.1
10
100
1000
10000
RSET [kohm]
Doc. No. 5009, Rev. B
8
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3606
TYPICAL CHARACTERISTICS
VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, TAMB = 25˚C, unless otherwise specified.
Foldback Current Limiting
RSET Pin Voltage vs. Temperature
1.24
RSET PIN VOLTAGE [v]
OUTPUT VOLTAGE [v]
5
1x mode
4
3
2
1
0
1.22
1.20
1.18
1.16
0
100
200
300
400
OUTPUT CURRENT [mA]
500
-50
-25
0
25
50
75
100
125
TEMPERATURE [°C]
PWM Dimming at 1kHz on ENM and ENS
RECOMMENDED LAYOUT
When the driver is in the 1.5x charge pump mode,
the 1MHz switching frequency operation requires
to minimize trace length and impedance to ground
on all 4 capacitors. A ground plane should cover the
area on the bottom side of the PCB opposite to the
IC and the bypass capacitors. Capacitors Cin and
Cout require short connection to ground which can
be done with multiple vias as shown on Figure 2. A
square copper area matches the QFN16 exposed
pad (GND) and must be connected to the ground
plane underneath. The use of multiple via will
improve the heat dissipation.
Figure 2: PCB Layout
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
9
Doc. No. 5009, Rev. B
CAT3606
PACKAGE DRAWING AND DIMENSIONS
THIN QFN 16-LEAD 4MM X 4MM
Recommended Land Pattern
4.41 mm
1.95 mm
2.25 mm
4.00+0.10
(S)
0.65 mm
0.76 mm
2.25 mm
PIN 1
INDEX AREA
4.00+0.10
(S)
0.35 mm
0.20 REF.
0.75+0.05
DAP SIZE 2.5 X 2.5
2.10+0.10
2.10+0.10
NOTE:
1. ALL DIMENSIONS ARE
IN mm. ANGLES IN DEGREES.
C0.35
0.55+0.10
0.0-0.05
0.30+0.05
0.65 TYP
3. WARPAGE SHALL NOT
EXCEED 0.10mm.
4. PACKAGE LENGTH/PACKAGE
WIDTH ARE CONSIDERED AS
SPECIAL CHARACTERISTIC. (S)
1.95 REF. (2x)
Doc. No. 5009, Rev. B
2. COPLANARITY APPLIES
TO THE EXPOSED PAD AS
WELL AS THE TERMINALS.
COPLANARITY SHALL NOT
EXCEED 0.08mm.
10
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
REVISION HISTORY
Date
Rev.
Reason
1/21/2005
A
Initial issue
08/01/2005
B
Update LED Current Setting
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Corporate Headquarters
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Phone: 408.542.1000
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Publication #:
Revison:
Issue date:
5009
B
08/01/05
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