Document
CL325
3-Channel 25mA Linear LED Driver
Features
► ±6% current accuracy @ 4.0 -15V ► 90V standoff voltage ► Separate enable pins for each channel allow for PWM dimming www.DataSheet4U.com ► Over-temperature protection ► 8-Lead SOIC (w/Heat Slug) package
General Description
The CL325 is designed to drive 3 strings of LEDs at a constant current of 25mA. Other drivers with currents in the range of 20 - 30mA are available. The drive current is fixed, with a ±6% tolerance over a VOUT range of 4 - 15V. Separate enable pins for each channel allow for PWM dimming, 3-step linear dimming, or individual disconnection of faulty LED strings. Over-temperature protection circuitry shuts down all 3 channels when the nominal die temperature reaches 135°C. Normal operation resumes when the die temperature drops by 30°C. The CL325 is available in the 8-Lead SOIC (w/Heat Slug) package and requires a single ceramic bypass capacitor which may be shared among several drivers.
Applications
► LCD backlighting ► Indicator lamps
Block Diagram and Typical Application Circuit
6.5 - 90V
CIN 100nF
8 7 6 5
VIN
OUT1 VDD
OUT2
OUT3
REG Host Controller
1 2 3
EN1 EN2 EN3 GND
CL325
4
CL325
Ordering Information
Device CL325
-G indicates package is RoHS compliant (‘Green’)
Underside plate is ground
EN2 EN1 GND EN3
Pin Configuration
OUT3 OUT2 OUT1 VIN
8-Lead SOIC (w/Heat Slug) CL325SG-G
8-Lead SOIC (w/Heat Slug) (SG)
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Absolute Maximum Ratings
Parameter Supply voltage, VIN Value -0.5V to +100V -0.5V to +100V -0.5V to +6.5V -40°C -65°C to +150°C
Product Marking
YYWW
CL325
LLLL
Output voltage, VOUT Enable voltage, VEN Operating temperature(1) Storage temperature
YY = Year Sealed WW = Week Sealed L = Lot Number = “Green” Packaging
8-Lead SOIC (w/Heat Slug) (SG)
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground. Note: (1) Maximum junction temperature internally limited.
Recommended Operating Conditions (all voltages with respect to GND pin)
Sym VIN VOUT fEN TJ CIN Parameter Supply voltage Output voltage Enable toggling frequency Junction temperature VIN capacitor Min 6.5 4.0 0 -40 Typ 100 Max 90 15 90 100 119 Units V V V kHz
o
Conditions --EN = 0 EN = 1 -------
C
nF
Thermal Characteristics
Sym θJA TLIM THYS Parameter Thermal resistance, junction to ambient Over-temperature limit Over-temperature hysteresis Min 120 Typ 48 135 30 Max 150 Units Conditions
O
C/W Mounted on JEDEC test PCB (2s 2p)
O O
C C
-----
2
CL325
Electrical Characteristics
(Over recommended operating conditions. TJ @ 25OC unless otherwise specified.)
Sym IIN IOUT(OFF) IOUT(ON)
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Parameter VIN supply current Output current, off
Min -
Typ 220 2.2 4.0 25.0 25.0 5.0 2.0 1.0 440 170
Max 250 2.3 10 26.5 26.5 27.5 0.8 10 1.0 1.0 2.4 1.2 800 250
Units Conditions µA mA µA EN1-3 = 1 EN1-3 = 0 ENX = 1 ENX = 0, VOUT = 0 - 4.0V mA ENX = 0, VOUT = 4.0 - 15V ENX = 0, VOUT = 15 - 90V V V pF µA µA µs µs ns ns ------VEN = 0V VEN = 5.0V ---------
Output current, on
23.5 22.5
VEN(ON) CEN IENL IENH tON tRISE tOFF tFALL
Enable voltage, on Enable voltage, off Enable input capacitance Enable low input current Enable high input current Enable on delay Output current rise time Enable off delay Output current fall time
2.4 -
VEN(OFF)
Timing
VEN(OFF)
EN
VEN(ON)
tON tRISE
90% IOUT(ON)
tOFF tFALL
IOUT
10% IOUT(ON)
Temperature Effects
Current (Normalized to 25°C)
1.05 1.00 0.95 0.90 0.85 0.80 -50
-40 25 120
0
50
100
150
Junction Temperature (°C)
3
CL325
Load Regulation
1.20
IOUT (normalized to nominal)
1.00 0.80 0.60 0.40 0.20 scale change 0 0 5 10 15 20 40 60 80 100
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VOUT (V)
Pin Description
Pin # 1,2,3 4 5,6,7 8 Underside Plate Name EN1, EN2, EN3 GND OUT1, OUT2, OUT3 VIN GND Description Output enable, active low. Circuit common. Constant current output (sinking). Connect the cathodes of the LEDs to these pins. Supply voltage. 6.5V to 90V. Bypass locally with a 100nF capacitor to ground. The exposed underside plate is internally connected to the GND pin. The plate may either be left floating or connected to ground. Solder the plate to an exposed copper area on the PCB for heatsinking purposes (see recommended layout).
Recommended PCB Layout
1cm2 exposed copper
Underside plate soldered to copper area Exposed copper area may be plated
1cm2 exposed copper
4
CL325
Higher LED Current
VLL
CIN 100nF
8 7 6 5
VIN
OUT1 VDD
OUT2
OUT3
REG
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Host Controller
1 2 3
EN1 EN2 EN3 GND
CL325
4
By paralleling outputs, higher LED currents can be achieved. In addition, linear dimming in 3 discrete steps may be obtained by enabling 1, 2, or 3 outputs.
Lowering CL325 Power Dissipation: Separate VIN Supply
VLL VIN CIN 100nF
8 7 6 5
VIN
OUT1 VDD
OUT2
OUT3.