Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests
are at the specified temperature and are pulsed tests, therefore: T
J
= T
C
= T
A
Operating continuously at a junction temperature of +135°C will shorten the life of the device while the thermal shutdown may trigger at a higher temperature than
+135°C since it is a typical number.
NOTE:
1.
JA
is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
Tech Brief TB379.
2. For
JC
, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications
PARAMETER
VIN
VIN
V
BAT
V
BATFAULT
I
S
E
N
I
S
D
IS
R
SWITCH
V
DC
R
OUTOL
R
OUTCL
I
OUT
I
LIMBOOST
I
LIMBUCK
OVPH
OVPL
V
GATE
V
GATE
V
FB
V
BAT
= V
IN
= 12V, V
DC
= 5V, T
A
= -40°C to +105°C unless otherwise specified.
CONDITIONS
I
OUT
= 350mA, 8 LEDs, BUCK/BOOSTN =
GND
I
OUT
= 350mA, 5 LEDs, BUCK/BOOSTN =
GND, TMAX disabled
Normal operating range
If V
BAT
> V
BATFAULT
, FAULT pin is
switched to ground
No switching, EN/PWM = 1
No switching, EN/PWM = 0
I
SWITCH
= 600mA
4.75
V
IN
< V
DC
V
IN
> 6V, F < 100Hz
4 LED output string. V
IN
= V
BAT
= 10V
BUCK/BOOSTN = GND
BUCK/BOOSTN = VDC
Upper threshold to enter overvoltage fault
mode, T
A
= +25°C
Lower threshold to exit overvoltage fault
mode, T
A
= +25°C
V
IN
- V
FAULT
V
FAULT
- V
IN
System in regulation, V
LEVEL
= 1V,
VIN = 12V, 6 LEDs
9.76
8.16
0.19
31
1
3.6
2.4
32
20
12.2
10.2
0.2
23
14.64
12.24
0.21
MIN
5
2.7
2.7
17.6
21
2.7
0.6
0.15
5
TYP
MAX
16
12
16
24
3.5
2.5
0.25
5.25
40
6.5
UNIT
V
V
V
V
mA
µA
V
A
A
A
V
V
V
V
V
DESCRIPTION
Input Supply Voltage
Input Supply Voltage
Input Supply Monitor
Supply Fault Threshold
Supply Current in V
IN
Supply Current in V
IN
Power FET On Resistance
Regulated Auxiliary Supply
Auxiliary Supply Open Loop Output
Resistance
Auxiliary Supply Closed Loop Output
Resistance
Output Drive Current
Power Switch Current Limit
Power Switch Current Limit
Over Voltage Positive Going Voltage
Mode Threshold
Over Voltage Negative Going Voltage
Mode Threshold
Protection FET VGS (gate clamp)
Protection FET VGS (gate clamp)
Feedback Voltage
FN6428 Rev 1.00
April 2, 2007
Page 2 of 20
ISL97801
Electrical Specifications
PARAMETER
V
LEVEL
FB
UV FAULT
FB
OV FAULT
f
SW
f
DIMMING
t
SWITCH
RLS
DRIVERL
RLS
DRIVERH
t
FAULT
t
DELAY
V
FAULTPUMP
V
BOOST
V
BUCK
V
MODEL
V
MODEH
en
FAULT
dis
FAULT
en
TEMP
dis
TEMP
T
COMPP
T
COMPN
T
TRIP
T
HYS
VEN/PWM
L
VEN/PWM
H
V
DCUVLO
Rschottky
.
V
BAT
= V
IN
= 12V, V
DC
= 5V, T
A
= -40°C to +105°C unless otherwise specified.
(Continued)
CONDITIONS
MIN
0.25
120
220
850
Mode = 1, modulation signal applied to
EN/PWM
C
GATE
= 2nF
EN/PWM = 0
EN/PWM = 3V
40
Timed LX switching delay
V
BAT
= V
IN
= 3V
BUCK/BOOSTN = GND
BUCK/BOOSTN = V
DC
MODE = GND
MODE = V
DC
2/3V
DC
0.9V
DC
0.96V
DC
0.5
0.08
VTEMP/VDC = 0.80
VTEMP/VDC = 0.20
1.26
0.74
135
25
1.2
2.5
2.6
15
23
°C
°C
V
V
V
0.94V
DC
1/3V
DC
0.85
6
0.4V
DC
160
250
1000
10
100
30
30
50
1
50
50
58
1.17
TYP
MAX
3
180
280
1150
UNIT
V
mV
mV
kHz
kHz
ns
ms
ms
V
V
V
V
V
V
V
V
V
DESCRIPTION
Light Control Voltage Linear Input Range Mode = 1, analog control of LED current
Feedback Undervoltage Fault
Feedback Overvoltage Fault
Switching Frequency
Maximum Recommended PWM
Dimming Frequency
Load Switch Transition Time
Load Switch Driver Impedance Low
Load Switch Driver Impedance High
Fault Timer Period
Start-up Delay
Fault Pin Charge Pump
Boost Mode Threshold
Buck Mode Threshold
Mode Low Threshold
Mode High Threshold
Input Level Applied to TMAX Pin to
Enable Fault Protection
Input Level Applied to TMAX Pin to
Disable Fault Protection
Input Level Applied to TEMP Pin to
Enable Temperature Compensation
Input Level Applied to TEMP Pin to
Disable Temperature Compensation
VFB Positive Temperature
Compensation; VFB/VFBnom
VFB Negative Temperature
Compensation; VFB/VFBnom
Internal Temperature Protection
Threshold
Internal Temperature Protection
Hysteresis
EN/PWM Pin Input Low Threshold
EN/PWM Pin Input High Threshold
V
DC
Under Voltage Lockout
Internal Schottky Diode for Buck
VLEVEL = 1V, EN/PWM = 3V
VLEVEL = 1V, EN/PWM = 3V
TABLE 1. LIGHT OUTPUT CONTROL, V
DC
= 5.0V
MODE
1
Don’t Care
0
TEMP
OPERATING MODE
(VDC - 0.25) > V > 0.25V
Standard Mode
light level to PWM modulation of EN/PWM input; LED bias current determined by
LEVEL voltage, nominal 1V
V < 0.25V
V < (VDC - 0.25)
Disable temperature compensation
Fixed Bias Mode
V
FB
level internally set to 0.4V, independent of V
LEVEL
FN6428 Rev 1.00
April 2, 2007
Page 3 of 20
ISL97801
Typical Performance Curves
100
8 LEDs
I
LEDpeak
= 380mA
95
90
EFFICIENCY (%)
85
80
75 99%@1kHz
70
65
60
6
8
10
12
V
IN
(V)
14
16
18
10%@10kHz
50%@100Hz
10%@1kHz
10%@100Hz
50%@1kHz
100
99%@100Hz
99%@10kHz
EFFICIENCY (%)
95
90
85
80
75
70
65
60
4
6
8
99% @ 100Hz
10% @ 100Hz
10
V
IN
(V)
12
14
16
10% @ 10kHz
5 LEDs
I
LEDpeak
= 380mA
99% @ 10kHz
50%@10kHz
FIGURE 1. 8 LEDs EFFICIENCY vs INPUT VOLTAGE vs
DIMMING FREQUENCY AND DUTY CYCLE
FIGURE 2. 5 LEDs EFFICIENCY vs INPUT VOLTAGE vs
DIMMING FREQUENCY AND DUTY CYCLE
100
100
95
99%@100Hz
EFFICIENCY (%)
99%@10kHz
90
85
80
75
70
65
10
60
0
5 LEDs
I
LEDpeak
= 380mA
PWM = 10kHz
8 LEDs, V
IN
= 12V
5 LEDs, V
IN
= 9V
20
40
60
80
PWM DIMMING DUTY CYCLE (%)
100
8 LEDs
3 LEDs
95 I
LEDpeak
= 380mA
90
EFFICIENCY (%)
85
80
75
70
65
60
4
6
V
IN
(V)
10%@100Hz
8
10%@10kHz
FIGURE 3. 3 LEDs EFFICIENCY vs INPUT VOLTAGE vs
DIMMING FREQUENCY AND DUTY CYCLE
FIGURE 4. 8 AND 5 LEDs EFFICIENCY vs PWM DUTY CYCLE
400
350
I
LEDpeak
= 380mA
4
5 LEDs @ 100Hz
3 LEDs @ 100Hz
I
LED
(%)
3
2
1
0
-1
-2
-3
-4
-5
60
80
100
-6
6
8
99% @ 10kHz
99% @ 100Hz
10
12
V
IN
(V)
14
16
18
10% @ 10kHz
8 LEDs
I
LEDpeak
= 380mA
8 LEDs, V
IN
= 12V
5 LEDs, V
IN
= 9V
300
3 LEDs, V
IN
= 5V
I
LED
(mA)
250
200
150
100
50
0
0
8 LEDs @ 1kHz
10% @ 100Hz
8 LEDs @ 10kHz
5 LEDs @ 10kHz
20
40
PWM DIMMING DUTY CYCLE (%)
FIGURE 5. LEDs PWM DIMMING LINEARITY
FIGURE 6. 8 LEDs CURRENT ACCURACY vs INPUT VOLTAGE
FN6428 Rev 1.00
April 2, 2007
Page 4 of 20
ISL97801
Typical Performance Curves
(Continued)
10
8
6
4
I
LED
(%)
I
LED
(%)
2
0
-2
-4
-6
-8
-10
4
10% @ 10kHz
99% @ 10kHz
99% @ 100Hz
6
8
10
V
IN
(V)
12
14
16
10% @ 100Hz
5 LEDs
I
LEDpeak
= 380mA
16
14
12
10
8
6
4
2
0
-2
-4
4
5
6
7
V
IN
(V)
8
9
10
99% @ 100Hz
99% @ 10kHz
3 LEDs
I
LEDpeak
= 380mA
FIGURE 7. 5 LEDs CURRENT ACCURACY vs INPUT VOLTAGE
FIGURE 8. 3 LEDs CURRENT ACCURACY vs INPUT VOLTAGE
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