Catalyst CAT3614HV2-T2 4-channel 1-wire led driver in 3x3mm package Datasheet

CAT3614
4-Channel 1-Wire LED Driver in
3x3mm Package
FEATURES
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DESCRIPTION
Drives up to 4 LED channels
1-wire EZDimTM Programmable LED Current
Accurate 1mA Dimming Level
Power efficiency up to 91%
Fractional pump 1x/1.5x
Low noise input ripple
Fixed High Frequency Operation 1MHz
“Zero” Current Shutdown Mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
12-lead TDFN 3mm x 3mm package
The CAT3614 is a high efficiency 1x/1.5x fractional
charge pump with programmable dimming current in
four LED channels. To ensure uniform brightness in
LCD backlight applications, each LED channel
delivers an accurate regulated current.
Low noise and input ripple is achieved by operating
at a constant switching frequency of 1MHz which
allows the use of small external ceramic capacitors.
The 1x/1.5x fractional charge pump supports a wide
range of input voltages from 3V to 5.5V with
efficiency up to 91%, and is ideal for Li-Ion battery
powered devices.
The EN/DIM logic input provides a 1-wire EZDimTM
interface for dimming control of the LEDs. When
enabled, a series of clock pulses reduces the LED
brightness in 1mA steps on each negative going
edge. Currents from 0mA to 31mA are supported.
APPLICATIONS
„ LCD Display Backlight
„ Cellular Phones
The device is available in the tiny 12-lead thin DFN
3mm x 3mm package with a max height of 0.8mm.
„ Digital Still Cameras
„ Handheld Devices
ORDERING INFORMATION
Part Number
CAT3614HS2-T2
Package
TDFN-12 3x3
Quantity
per Reel
2000
Package
Marking
HAAB
CAT3614HV2-T2
TDFN-12 3x3 Green
2000
HAAA
Typical Application Circuit
Pin Configuration
Top View
12-lead TDFN 3mm x 3mm
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Note: Unused LED channels must be connected to
VOUT.
1
Doc. No. 25095, Rev. 01
CAT3614
ABSOLUTE MAXIMUM RATINGS
Parameter
Rating
Unit
VIN, LEDx voltage
6
V
VOUT, C1±, C2± voltage
7
V
EN/DIM voltage
VIN + 0.7V
V
Storage Temperature Range
-65 to +160
°C
Junction Temperature Range
-40 to +125
°C
300
°C
Lead Temperature
RECOMMENDED OPERATING CONDITIONS
Parameter
Range
Unit
VIN
3 to 5.5
V
-40 to +85
°C
ILED per LED pin
0 to 31
mA
Total Output Current
0 to 124
mA
Ambient Temperature Range
Typical application circuit with external components are shown on page 1.
ELECTRICAL OPERATING CHARACTERISTICS (over recommended operating conditions
unless specified otherwise) VIN = 3.6V, EN = High, ambient temperature of 25ºC.
Symbol Parameter
Conditions
Min
Typ
Max
IQ
Quiescent Current
0.3
0.5
1
1x mode, no load
1.5x mode, no load
1
3
8
IQSHDN
Shutdown Current
VEN = 0V
ILED-ACC
LED Current Accuracy
1mA ≤ ILED ≤ 31mA
ILED-DEV
LED Channel Matching
Output Resistance (open loop)
ROUT
Unit
mA
mA
1
µA
±3
±8
%
(ILED - ILEDAVG) / ILEDAVG
±3
±7
%
1x mode, IOUT = 100mA
1.5x mode, IOUT = 100mA
0.4
2.6
1
7
Ω
Ω
0.8
1
1.3
MHz
FOSC
Charge Pump Frequency
ISC_MAX
Output short circuit Current Limit
VOUT < 0.5V
30
60
100
mA
IIN_MAX
Input Current Limit
1x mode, VOUT > 1V
200
300
600
mA
1
0.4
µA
V
V
EN/DIM Pin
Input Leakage
Logic High Level
Logic Low Level
-1
1.3
TSD
Thermal Shutdown
145
165
175
ºC
THYS
Thermal Hysteresis
10
20
30
ºC
Undervoltage lock out (UVLO)
threshold
1.7
2
2.4
V
IEN/DIM
VHI
VLO
VUVLO
Doc. No. 25095, Rev. 01
2
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3614
Recommended EN/DIM Timing
For 3V ≤ VIN ≤ 5.5V, over full ambient temperature range -40 to +85ºC.
Symbol Parameter
TSETP
Conditions
Min
Typ
Max
Unit
EN/DIM setup from shutdown
10
TLO
EN/DIM program low time
0.3
THI
EN/DIM program high time
0.3
µs
EN/DIM low time to shutdown
1.5
ms
TOFF
TD
TDEC
µs
200
µs
LED current enable
40
µs
LED current decrement
0.1
µs
Figure 1. LED Dimming Timing Diagram
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. 25095, Rev. 01
CAT3614
Typical Characteristics
VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1µF, TAMB = 25°C unless otherwise specified.
Efficiency vs. Input Voltage (4 LEDs)
Efficiency vs. Total LED Current (4 LEDs)
100
100
20mA per LED
90
1x mode
EFFICIENCY [%]
EFFICIENCY [%]
90
80
70
10mA per LED
60
50
70
60
VIN = 3.2V (1.5x mode)
40
4.2
4.0
3.8
3.6
3.4
3.2
INPUT VOLTAGE [V]
0
3.0
25
50
75
100
125
TOTAL LED CURRENT [mA]
Quiescent Current vs. Input Voltage (1x mode)
Quiescent Current vs. Temperature (1x mode)
0.8
QUIESCENT CURRENT [mA]
0.8
QUIESCENT CURRENT [mA] .
80
50
1.5x mode
40
0.6
0.4
4 LEDs OFF
0.2
0.6
0.4
4 LEDs OFF
0.2
0.0
0.0
3.0
3.2
3.4
3.6
3.8
4.0
INPUT VOLTAGE [V]
-40
4.2
0
40
80
TEMPERATURE [°C]
120
Quiescent Current vs. Temperature (1.5x mode)
Quiescent Current vs. Input Voltage (1.5x mode)
6.0
6.0
QUIESCENT CURRENT [mA]
QUIESCENT CURRENT [mA] .
VIN = 4V (1x mode)
5.0
4.0
3.0
2.0
4 LEDs OFF
1.0
0.0
3.0
3.2
3.4
3.6
3.8
4.0
4.0
3.0
2.0
4 LEDs OFF
1.0
0.0
4.2
-40
INPUT VOLTAGE [V]
Doc. No. 25095, Rev. 01
5.0
4
0
40
80
TEMPERATURE [°C]
120
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3614
Typical Characteristics
VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1µF, TAMB = 25°C unless otherwise specified.
LED Current Change vs. Temperature
5.0
5.0
4.0
3.0
4.0
LED CURRENT CHANGE [%]
LED CURRENT CHANGE [%] .
LED Current Change vs. Input Voltage
1x Mode
2.0
1.0
0.0
-1.0
-2.0
1.5x Mode
-3.0
-4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-5.0
3.0
3.2
3.4
3.6
3.8
4.0
4.2
-40
INPUT VOLTAGE [V]
80
1.3
CLOCK FREQUENCY [MHz]
1.3
CLOCK FREQUENCY [MHz]
0
20
40
60
TEMPERATURE [°C]
Oscillator Frequency vs. Temperature
Oscillator Frequency vs. Input Voltage
1.2
1.1
1.0
4 LEDs at 20mA
0.9
0.8
0.7
1.2
1.1
1.0
0.9
0.8
0.7
3.0
3.2
3.4
3.6
3.8
INPUT VOLTAGE [V]
4.0
-40
Output Resistance vs. Input Voltage (1x mode)
0
40
80
TEMPERATURE [°C]
120
Output Resistance vs. Input Voltage (1.5x mode)
4.0
OUTPUT RESISTANCE [Ω] .
1.0
OUTPUT RESISTANCE [Ω] .
-20
0.8
0.6
0.4
0.2
3.5
3.0
2.5
2.0
1.5
1.0
0.0
3.0
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3.0
4.2
5
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
4.2
Doc. No. 25095, Rev. 01
CAT3614
Typical Characteristics
VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1µF, TAMB = 25°C unless otherwise specified.
Power Up with 4 LEDs at 15mA (1x Mode)
Power Up with 4 LEDs at 15mA (1.5x Mode)
Enable Power Down Delay (1x Mode)
Enable Power Down Delay (1.5x Mode)
Switching Waveforms in 1.5x Mode
Operating Waveforms in 1x Mode
Doc. No. 25095, Rev. 01
6
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3614
Typical Characteristics
VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1µF, TAMB = 25°C unless otherwise specified.
Enable and Output Current Dimming Waveforms
Line Transient Response (3.6V to 5.5V) 1x Mode
Enable Low Minimum Program Time vs.
Temperature
Enable High Minimum Program Time vs. Temperature
200
VIN = 3.5V
160
MINIMUM TIME [nS] .
MINIMUM TIME [nS] .
200
VIN = 3.5V
120
80
VIN = 4.2V
40
0
-40
0
40
80
TEMPERATURE [°C]
160
120
VIN = 4.2V
80
40
0
120
-40
0
40
80
120
TEMPERATURE [°C]
Enable Voltage Threshold vs. Temperature
Foldback Current Limit
4.0
1.0
OUTPUT VOLTAGE [V]
ENABLE VOLTAGE [V]
1.2
0.8
0.6
0.4
0.2
0.0
3.5
3.0
1x Mode
2.5
VIN = 3.5V
2.0
1.5
1.0
0.5
0.0
-40
0
40
80
120
0
TEMPERATURE [°C]
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
7
100
200
300
OUTPUT CURRENT [mA]
400
Doc. No. 25095, Rev. 01
CAT3614
PIN DESCRIPTIONS
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
TAB
Name
VIN
C1+
C1C2C2+
GND
LED1
LED2
LED3
LED4
EN/DIM
VOUT
TAB
Function
Supply voltage.
Bucket capacitor 1 terminal
Bucket capacitor 1 terminal
Bucket capacitor 2 terminal
Bucket capacitor 2 terminal
Ground reference
LED1 cathode terminal (if not used, connect to VOUT)1
LED2 cathode terminal (if not used, connect to VOUT)1
LED3 cathode terminal (if not used, connect to VOUT)1
LED4 cathode terminal (if not used, connect to VOUT)1
Device enable (active high) and dimming control input
Charge pump output connected to the LED anodes
Connect to GND on the PCB
Note:
(1) LED1, LED2, LED3, LED4 pins should not be left floating. They should be connected to the LED cathode, or tied to VOUT pin if not used.
PIN FUNCTION
VOUT is the charge pump output that is connected
to the LED anodes. A small 1µF ceramic bypass
capacitor is required between the VOUT pin and
ground near the device.
VIN is the supply pin for the charge pump. A small
1µF ceramic bypass capacitor is required between
the VIN pin and ground near the device. The
operating input voltage range is from 2.2V to 5.5V.
Whenever the input supply falls below the
undervoltage threshold (2V) all LEDs channels will
be automatically disabled.
GND is the ground reference for the charge pump.
The pin must be connected to the ground plane on
the PCB.
EN/DIM is the enable and dimming control logic
input for all LED channels. Guaranteed levels of
logic high and logic low are set at 1.3V and 0.4V
respectively. When EN/DIM is initially taken high, the
device becomes enabled and all LED currents
remain at 0mA. The falling edge of the first pulse
applied to EN/DIM sets all LED currents to their full
scale of 31mA.
C1+, C1- are connected to each side of the 1µF
ceramic bucket capacitor C1.
C2+, C2- are connected to each side of the 1µF
ceramic bucket capacitor C2.
LED1 to LED4 provide the internal regulated current
for each of the LED cathodes. These pins enter a
high impedance zero current state whenever the
device is placed in shutdown mode. In applications
using less than four LEDs, all unused channels
should be wired directly to VOUT. This ensures the
channel is automatically disabled dissipating less
than 200µA.
On each consecutive falling edge of the pulse
applied to EN/DIM, the LED current is decreased by
1mA step. On the 32nd pulse, the LED current is set
to zero. The next pulse on EN/DIM resets the current
back to their full scale of 31mA.
TAB is the exposed pad underneath the package.
For best thermal performance, the tab should be
soldered to the PCB and connected to the ground
plane.
To place the device into zero current shutdown
mode, the EN/DIM pin must be held low for 1.5ms or
more.
Doc. No. 25095, Rev. 01
8
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3614
BLOCK DIAGRAM
Figure 2. CAT3614 Functional Block Diagram
BASIC OPERATION
At power-up, the CAT3614 starts operating in 1x
mode where the output will be approximately equal
to the input supply voltage (less any internal voltage
losses). If the output voltage is sufficient to regulate
all LED currents the device remains in 1x operating
mode.
In 1.5x mode, the output is approximately equal to
1.5 times the input supply voltage (less any internal
voltage losses).
The above sequence is repeated each and every
time the chip is powered-up or is taken out of
shutdown mode (via EN/DIM pin).
If the input voltage is insufficient or falls to a level
where the regulated currents cannot be maintained,
the device automatically switches (after a fixed
delay of 400µs) into 1.5x mode.
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
9
Doc. No. 25095, Rev. 01
CAT3614
LED Current Setting
The driver enters a thermal shutdown mode as soon
as the die temperature exceeds about +165ºC.
When the device temperature drops down by about
20ºC, the device resumes normal operation.
Figure 1 shows the timing diagram necessary at the
EN/DIM input for setting the LED currents.
The EN/DIM set up time requires the signal to be
held high for 10µs or longer to ensure the
initialization of the driver at power-up. Each
subsequent pulse on the EN/DIM (300ns to 200µs
pulse duration) steps down the LED current from full
scale of 31mA to zero with a 1mA resolution.
Consecutive pulses should be separated by 300ns
or longer. Pulsing beyond the 0mA level restores the
current level back to full scale and the cycle repeats.
Pulsing frequencies from 5kHz up to 1MHz can be
supported during dimming operations. When the
EN/DIM is held low for 1.5ms or more, the CAT3614
enters the shutdown mode and draws “zero” current.
External Components
The driver requires a total of four external 1µF
ceramic capacitors: two for decoupling input and
output, and two for the charge pump. Both capacitor
types X5R and X7R are recommended for the LED
driver application. In the 1.5x charge pump mode,
the input current ripple is kept very low by design,
and an input bypass capacitor of 1µF is sufficient. In
1x mode, the device operating in linear mode does
not introduce switching noise back onto the supply.
Recommended Layout
In 1.5x charge pump mode, the driver switches
internally at a high frequency of 1MHz. It is
recommended to minimize trace length to all four
capacitors. A ground plane should cover the area
under the driver IC as well as the bypass capacitors.
Short connection to ground on capacitors Cin and
Cout can be implemented with the use of multiple
vias. A copper area matching the TDFN exposed
pad (GND) must be connected to the ground plane
underneath. The use of multiple vias improves the
package heat dissipation.
For applications with three LEDs or less, any unused
LED pins should be tied to VOUT, as shown on
Figure 3.
Protection Mode
If an LED becomes open-circuit, the output voltage
VOUT is internally limited to about 5.5V. This is to
prevent the output pin from exceeding its absolute
maximum rating.
Figure 3. Three LED Application
Doc. No. 25095, Rev. 01
Figure 4. Single Flash LED Application
10
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3614
PACKAGE DRAWING AND DIMENSIONS
Thin DFN 12-Lead 3mm X 3mm, 0.45mm Pitch
RECOMMENDED LAND PATTERN
Dimensions in millimeters
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
11
Doc. No. 25095, Rev. 01
REVISION HISTORY
Date
02/09/2006
07/21/06
Rev.
00
01
Reason
Initial Release
Update Typical Application Circuit
Update Pin Descriptions
Update Electrical Operating Characteristics
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Document No: 25095
Revision:
01
Issue date:
07/21/2006
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