Catalyst CAT3612 Programmable 300ma camera flash led driver Datasheet

CAT3612
Programmable 300mA Camera Flash LED Driver
FEATURES
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PRODUCT DESCRIPTION
Dual matched regulated LED channels
300mA output current (150mA per channel)
1-wire EZDimTM Programmable LED Current
32 accurate dimming levels
Power efficiency up to 90%
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 CAT3612 is a high-efficiency 1x/1.5x fractional
charge pump with programmable current in two LED
channels. Each channel delivers accurate regulated
current up to 150mA and make CAT3612 ideal for
driving one or two flash LEDs.
Low noise operation 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 90%, and is ideal for Li-Ion battery
powered devices.
APPLICATION
The EN/DIM logic input provides a 1-wire EZDimTM
interface for dimming control of the LEDs. When
enabled, pulsing the EN/DIM reduces the LED
current on each negative edge in 31 linear steps
from 150mA down to zero current.
„ Camera Flash
„ Cellular Phones
„ Digital Still Cameras
ORDERING INFORMATION
Part Number
Package
The device is available in the tiny 12-lead thin DFN
3mm x 3mm package with a max height of 0.8mm.
Quantity Package
per Reel Marking
CAT3612HV2-T2 TDFN-12 3x3
Green *
2000
HAAD
Note *: Plated lead finish is Matte Tin.
For other lead finish option, please contact factory.
PIN CONFIGURATION
TYPICAL APPLICATION CIRCUIT
Top View
12-lead TDFN 3mm x 3mm
Note: Unused LED channel must be connected to VOUT
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. 5016 Rev. A
CAT3612
ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, LED1, LED2 voltage
VOUT, C1±, C2± voltage
EN/DIM voltage
Storage Temperature Range
Junction Temperature Range
Lead Temperature
Rating
6
7
VIN + 0.7V
-65 to +160
-40 to +125
300
Unit
V
V
V
°C
°C
°C
RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
ILED per LED pin
Total Output Current
Range
3 to 5.5
-40 to +85
0 to 150
0 to 300
Unit
V
°C
mA
mA
Typical application circuit with external components is 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
IQ
Quiescent Current
IQSHDN
ILED-ACC
ILED-DEV
ROUT
Shutdown Current
LED Current Accuracy
LED Channel Matching
Output Resistance (open loop)
FOSC
ISC_MAX
IIN_MAX
Charge Pump Frequency
Output short circuit Current Limit
Input Current Limit
EN/DIM Pin
• Input Leakage
• Logic High Level
• Logic Low Level
Thermal Shutdown
Thermal Hysteresis
Undervoltage lock out (UVLO)
Threshold
IEN/DIM
VHI
VLO
TSD
THYS
VUVLO
Doc. No. 5016 Rev. A
Conditions
1x mode, no load
1.5x mode, no load
VEN = 0V
5mA ≤ ILED ≤ 150mA
(ILED - ILEDAVG) / ILEDAVG
1x mode, IOUT = 100mA
1.5x mode, IOUT = 100mA
Min
Typ
0.5
3
Max
1
0.8
VOUT < 0.5V
1x mode, VOUT > 1V
±3
±3
0.4
2.6
1
60
350
-1
1.3
1.3
1
0.4
165
20
2
2
Unit
mA
mA
µA
%
%
Ω
Ω
MHz
mA
mA
µA
V
V
ºC
ºC
V
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3612
RECOMENDED EN/DIM TIMING
For 3V ≤ VIN ≤ 5.5V, over full ambient temperature range -40°C to +85°C.
Symbol
TSETP
TLO
THI
TOFF
TD
TDEC
Parameter
EN/DIM setup from shutdown
EN/DIM program low time
EN/DIM program high time
EN/DIM low time to shutdown
LED current enable
LED current decrement
Conditions
Min
10
0.3
0.3
1.5
Typ
Max
200
40
0.1
Unit
µs
µs
µs
ms
µs
µs
Figure 1. LED Dimming Timing Diagram
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. 5016 Rev. A
CAT3612
TYPICAL CHARACTERISTICS
VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified.
Efficiency vs. LED Current
Efficiency vs. Input Voltage
100
100
EFFICIENCY [%]
90
VF = 3V
80
70
60
IOUT = 250mA
50
40
4.0 3.8 3.6 3.4 3.2
INPUT VOLTAGE [V]
60
VIN = 3.2V (1.5x Mode)
50
100 150 200 250
LED CURRENT [mA]
300
Quiescent Current vs. Temperature (1x mode)
0.8
QUIESCENT CURRENT [mA]
0.8
QUIESCENT CURRENT [mA]
70
40
3.0
Quiescent Current vs. Input Voltage (1x mode)
0.6
0.4
0.2
LED Off
0.0
3.0
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
0.6
0.4
0.2
LED Off
0.0
-40
4.2
Quiescent Current vs. Input Voltage (1.5x mode)
0
40
80
TEMPERATURE [°C]
120
Quiescent Current vs. Temperature (1.5x mode)
6.0
6.0
QUIESCENT CURRENT [mA]
QUIESCENT CURRENT [mA]
80
50
IOUT = 100mA
4.2
VIN = 4.2V (1x Mode)
90
EFFICIENCY [%]
VF = 3.4V
5.0
4.0
3.0
2.0
1.0
LED Off
0.0
3.0
Doc. No. 5016 Rev. A
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
5.0
4.0
3.0
2.0
1.0
LED Off
0.0
-40
4.2
4
0
40
80
TEMPERATURE [°C]
120
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3612
TYPICAL CHARACTERISTICS
VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified.
LED Current Change vs. Temperature
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
LED CURRENT CHANGE [%]
LED CURRENT CHANGE [%]
LED Current Change vs. Input Voltage
1x Mode
1.5x Mode
3.0
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
4.2
-40
Oscillator Frequency vs. Input Voltage
120
1.3
CLOCK FREQUENCY [MHz]
CLOCK FREQUENCY [MHz]
0
40
80
TEMPERATURE [°C]
Oscillator Frequency vs. Temperature
1.3
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]
1.2
1.1
1.0
0.9
0.8
0.7
-40
4.0
0
40
80
TEMPERATURE [°C]
120
Output Resistance vs. Input Voltage(1.5x mode)
Output Resistance vs. Input Voltage (1x mode)
1.0
4.0
OUTPUT RESISTANCE [Ω] .
OUTPUT RESISTANCE [Ω] .
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
0.8
0.6
0.4
0.2
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
4.2
3.5
3.0
2.5
2.0
1.5
1.0
3.0
5
3.2 3.4 3.6 3.8 4.0
INPUT VOLTAGE [V]
4.2
Doc. No. 5016 Rev. A
CAT3612
TYPICAL CHARACTERISTICS
VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified.
Power Up with 1 LED at 100mA (1x Mode)
Power Up with 1 LED at 100mA (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. 5016 Rev. A
6
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3612
TYPICAL CHARACTERISTICS
VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified.
Enable and Output Current Dimming Waveforms
Line Transient Response (3.6V to 5.5V) 1x Mode
Enable High Minimum Program Time vs. Temperature
Enable Low Minimum Program Time vs. Temperature
200
200
MINIMUM TIME [nS] .
MINIMUM TIME [nS] .
VIN = 3.5V
160
VIN = 3.5V
120
80
VIN = 4.2V
40
160
120
VIN = 4.2V
80
40
0
0
-40
0
40
80
TEMPERATURE [°C]
-40
120
40
80
120
TEMPERATURE [°C]
Foldback Current Limit
Enable Voltage Threshold vs. Temperature
1.2
4.0
1.0
3.5
OUTPUT VOLTAGE [V]
EN A B LE V OLTA G E [V ]
0
0.8
0.6
0.4
0.2
0.0
3.0
1x Mode
LED Off
2.5
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
100 200 300 400
OUTPUT CURRENT [mA]
500
Doc. No. 5016 Rev. A
CAT3612
PIN DESCRIPTIONS
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
TAB
Name
VIN
C1+
C1C2GND
LED1
LED2
C2+
EN/DIM
VOUT
TAB
Function
Supply voltage.
Bucket capacitor 1 terminal
Bucket capacitor 1 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.
Bucket capacitor 2 terminal
Not connected
Device enable (active high) and dimming control input.
Not connected
Charge pump output connected to the LED anodes.
Connect to GND on the PCB.
Note 1: LED1, LED2 pins should not be left floating. They should be connected to the LED cathode, or tied to the 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 device. A small 1µF
ceramic bypass capacitor is required between the VIN
pin and ground near the device. The operating input
voltage range is up to 5.5V. When the input supply
falls below the undervoltage threshold (2V), all LEDs
channels are 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 the LED currents remain at
0mA. The falling edge of the first pulse on EN/DIM
sets the LED currents to the full scale 150mA.
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, LED2 provide the internal regulated current for
each of the LED cathodes. These pins enter a high
impedance zero current state whenever the device is in
shutdown mode. In applications using only one LED
channel, the unused channel should be tied directly to
VOUT. The disabled channel only draws about 0.5mA.
On each consecutive falling edge of the pulse on
EN/DIM, the LED current decreases by 150/31mA. On
the 32nd pulse, the LED current is set to zero. The
next pulse on EN/DIM resets the current back to full
scale 150mA.
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. 5016 Rev. A
8
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3612
BLOCK DIAGRAM
Figure 2. CAT3612 Functional Block Diagram
BASIC OPERATION
At power-up, the CAT3612 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 LEDs
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 of
400µs) into 1.5x mode.
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
9
Doc. No. 5016 Rev. A
CAT3612
LED Current Setting
Table 1. Selection of LED current per Channel
Figure 1 shows the EN/DIM input timing diagram 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 150mA to zero with nearly 5mA
resolution. The selection of the LED current per
channel is shown in Table 1. 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 CAT3612 enters the shutdown
mode and draws “zero” current.
Number of pulses
on EN/DIM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
For applications with a single LED connected to one
LED pin only, the unused LED pin must be tied to
VOUT, as shown on Figure 3.
Figure 3. Single LED on one LED pin
LED current
(mA)
150
145
140
135.5
131
126
121
116
111
106.5
101.5
97
92
87
82
77.5
72.5
68
63
58
53
48.5
43.5
39
34
29
24
19
14.5
10
5
0
Figure 4. Application with 2 LEDs
Doc. No. 5016 Rev. A
10
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3612
Protection mode
Recommended Layout
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.
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 via.
A copper area matching the TDFN exposed pad
(GND) must be connected to the ground plane
underneath. The use of multiple via improves the
package heat dissipation.
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.
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.
Figure 5. Recommended Layout
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
11
Doc. No. 5016 Rev. A
CAT3612
PACKAGE DRAWING AND DIMENSIONS
Thin DFN 12-Lead 3mm x 3mm, 0.45mm Pitch
RECOMMENDED LAND PATTERN
Dimensions in millimeters
Doc. No. 5016 Rev. A
12
© 2006 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
REVISION HISTORY
Date
07/21/2006
Rev.
A
Reason
Initial Issue
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Document No: 5016
Revision:
A
Issue date:
07/21/2006
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