CAT3647
3-Channel Ultra High
Efficiency LED Driver with
32 Dimming Levels
Description
The CAT3647 is a high efficiencye fractional charge pump that can
drive up to three LEDs programmable by a one wire digital interface.
The inclusion of a 1.33x fractional charge pump mode increases
device efficiency by up to 10% over traditional 1.5x charge pumps
with no added external capacitors.
Low noise input ripple is achieved by operating at a constant
switching frequency which allows the use of small external ceramic
capacitors. The multi−fractional charge pump supports a wide range of
input voltages from 2.4 V to 5.5 V.
The EN/DIM logic input functions as a chip enable and a digital
dimming interface for setting the current in all the LED channels. The
1−wire pulse−dimming interface supports 32 linear steps from
full−scale down to zero current.
The device is available in the tiny 16−pad TQFN 3 mm x 3 mm
package with a max height of 0.8 mm.
ON Semiconductor’s 1.33x, charge pump switching architecture is
patented.
Features
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TQFN−16
HV3 SUFFIX
CASE 510AD
PIN CONNECTIONS
LED1
GND
NC
NC
LED2
LED3
NC
RSET
1
C2−
C2+
C1−
C1+
•
•
•
•
•
•
•
•
•
•
•
•
High Efficiency 1.33x Charge Pump
Charge Pump: 1x, 1.33x, 1.5x, 2x
Drives up to 3 LEDs at 30 mA Each
1−wire EZDim 32 Linear Steps
Power Efficiency up to 92%
Low Noise Input Ripple in All Modes
“Zero” Current Shutdown Mode
Soft Start and Current Limiting
Short Circuit Protection
Thermal Shutdown Protection
16−pad TQFN Package
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
EN/DIM
VOUT
(Top View)
MARKING DIAGRAM
JAAP
AXXX
YWW
JAAP = CAT3647HV3−GT2
A = Assembly Location
XXX = Last Three Digits of Assembly Lot Number
Y = Production Year (Last Digit)
WW = Production Week (Two Digits)
Applications
•
•
•
•
ORDERING INFORMATION
Device
CAT3647HV3−GT2
(Note 1)
Package
TQFN−16
(Pb−Free)
Shipping
†
2,000/
Tape & Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
1. NiPdAu Plated Finish (RoHS−compliant).
©
Semiconductor Components Industries, LLC, 2014
August, 2014
−
Rev. 3
1
Publication Order Number:
CAT3647/D
VIN
NC
CAT3647
1
mF
C1+
C
IN
1
mF
VIN
CAT3647
EN/DIM
RSET
GND
LED1
LED2
LED3
C1− C2+
1
mF
C2−
VOUT
V
IN
2.4 V
to
5.5 V
V
OUT
C
OUT
1
mF
1−Wire
EZDimt
Programming
3.74 kΩ
20 mA
Figure 1. Typical Application Circuit
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, LEDx, C1±, C2±, EN/DIM, RSET voltage
VOUT voltage
Storage Temperature Range
Junction Temperature Range
Rating
6
7
−65
to +160
−40
to +150
Unit
V
V
°C
°C
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
Table 2. RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
I
LED
per LED pin
LED Forward Voltage Range
Rating
2.5 to 5.5
−40
to +85
up to 30
1.3 to 4.3
Unit
V
°C
mA
V
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond
the Recommended Operating Ranges limits may affect device reliability.
NOTE: Typical application circuit with external components is shown above.
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2
CAT3647
Table 3. ELECTRICAL OPERATING CHARACTERISTICS
(over recommended operating conditions unless specified otherwise) V
IN
= 3.6 V, EN = High, T
AMB
= 25°C
Symbol
I
Q
Quiescent Current
Name
Conditions
1x mode, excluding load
1.33x mode, excluding load
1.5x mode, excluding load
2x mode, excluding load
V
EN
= 0 V
RSET = 3.74 kW
RSET = 7.50 kW
I
LED-ACC
I
LED-DEV
V
RSET
R
OUT
LED Current Accuracy
LED Channel Matching
RSET Regulated Voltage
Output Resistance (open loop)
1x mode
1.33x mode, V
IN
= 3 V
1.5x mode, V
IN
= 2.7 V
2x mode, V
IN
= 2.4 V
1.33x and 2x mode
1.5x mode
V
OUT
< 0.5 V
V
OUT
> 1 V, 1x mode
0.8
1
(I
LEDAVG
– I
NOMINAL
) / I
NOMINAL
RSET = 4.99 kW
(I
LED
- I
LEDAVG
) / I
LEDAVG
0.58
20
10
±2
±1.5
0.6
0.8
5
5
10
1
1.3
50
250
130
400
120
100
1.3
0.4
150
20
1.6
1.8
2.0
1.3
1.6
0.62
%
%
V
W
Min
Typ
1.0
1.7
2.2
2.4
1
Max
Units
mA
I
QSHDN
I
LED-ACC
Shutdown Current
LED Current Setting
mA
mA
F
OSC
I
SC_MAX
I
IN_MAX
LED
TH
V
HYS
T
DF
R
EN/DIM
V
HI
V
LO
T
SD
T
HYS
V
UVLO
Charge Pump Frequency
Output short circuit Current Limit
Input Current Limit
1x to 1.33x or 1.33x to 1.5x or 1.5x to 2x
Transition Thresholds at any LED pin
1x Mode Transition Hysteresis
Mode Transition Filter Delay
EN/DIM Pin
−
Internal Pull-down Resistor
−
Logic High Level
−
Logic Low Level
Thermal Shutdown
Thermal Hysteresis
Undervoltage lockout (UVLO) threshold
MHz
mA
mA
mV
mV
ms
kW
V
V
°C
°C
V
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
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CAT3647
Table 4. RECOMMENDED EN/DIM TIMING
(For 2.4 V
≤
V
IN
≤
5.5 V, over full ambient temperature range -40°C to +85°C.)
Symbol
T
LO
T
HI
T
PWRDWN
T
LED
Name
EN/DIM program low time
EN/DIM program high time
EN/DIM low time to shutdown
LED current settling time
T
HI
EN/DIM
T
LO
T
LED
100%
LED
Current
97% 93%
32 Levels
3%
0%
100%
T
PWRDWN
Conditions
Min
0.2
0.2
1.5
40
Typ
Max
100
Units
ms
ms
ms
ms
Shutdown
Shutdown
Figure 2. EN/DIM Digital Dimming Timing Diagram
LED Current Setting
The full scale LED current is set by the external resistor
connected between the RSET pin and ground. Table 5 lists
standard resistor values for several LED current settings.
Table 5. RESISTOR RSET AND LED CURRENT
Full Scale LED Current [mA]
2
5
10
15
20
25
30
RSET [kW]
37.4
14.7
7.50
4.99
3.74
3.00
2.49
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CAT3647
TYPICAL PERFORMANCE CHARACTERISTICS
(V
IN
= 3.6 V, I
OUT
= 60 mA (3 LEDs at 20 mA), C
IN
= C
OUT
= C
1
= C
2
= 1
mF,
T
AMB
= 25°C unless otherwise specified.)
100
90
1x
EFFICIENCY (%)
EFFICIENCY (%)
80
70
60
50
40
2x
80
70
60
50
40
1.33x
V
F
= 3.3 V
100
1.33x
1.5x
90
V
F
= 3.3 V
1x
4.5
4.0
3.5
3.0
2.5
2.0
4.2
4.0
3.8
3.6
3.4
3.2
3.0
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 3. Efficiency vs. Input Voltage
4
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
V
F
= 3.3 V
3
4
Figure 4. Efficiency vs. Li−Ion Voltage
3
2x
1.5x
1.33x
1x
2
2
1
LEDs Off
0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1
0
−40
0
40
TEMPERATURE (°C)
80
120
INPUT VOLTAGE (V)
Figure 5. Quiescent Current vs. Input Voltage
10
LED CURRENT VARIATION (%)
6
4
2
0
−2
−4
−6
−8
−10
LED CURRENT VARIATION (%)
8
V
F
= 3.3 V
10
8
6
4
2
0
−2
−4
−6
Figure 6. Quiescent Current vs. Temperature
V
F
= 3.3 V
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
−8
−10
−40
0
40
TEMPERATURE (°C)
80
120
INPUT VOLTAGE (V)
Figure 7. LED Current Change vs. Input
Voltage
Figure 8. LED Current Change vs.
Temperature
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