A8500
Flexible WLED/RGB Backlight Driver
for Medium Size LCDs
ELECTRICAL CHARACTERISTICS, valid at TA = –40°C to 85°C, typical values at TA = 25°C, VIN = 5 V, unless otherwise noted
Characteristics
Symbol
Test Conditions
Min. Typ. Max. Units
Input Voltage Range
Undervoltage Lockout Threshold
UVLO Hysteresis Window
Supply Current
APWM Frequency Range
Error Amplifier
VIN
VUVLO
VUVLOhys
ISUP
fAPWM
VIN falling
Switching at no load, TA = 25°C
Shutdown EN = PWM = APWM = VIL
4.2
–
5.5
V
–
–
4
V
–
0.2
–
V
–
5
–
mA
–
0.1
1
µA
20
–
2000
kHz
Error Amplifier Open Loop Gain
Error Amplifier Unity Gain Bandwidth
Error Amplifier Transconductance
Error Amplifier Output Sink Current
Error Amplifier Output Source Current
Boost Controller
AVEA
UGBEA
GmEA
IEAsink
IEAsource
∆ICOMP = ±10 µA
VLED1-8 = 1 V
VLED1-8 = 0 V
–
60
–
–
3
–
–
850
–
–
280
–
–
–280
–
dB
MHz
µA/V
µA
µA
RFSET = 13 kΩ, SKIP = VIL
Switching Frequency
fSW
RFSET = 26.1 kΩ, SKIP = VIL
RFSET = 32.4 kΩ, SKIP = VIH
Minimum Switch Off-Time
tOFFmin
Logic Input Levels (APWM , EN, MODE, PWM, SELx, and SKIP pins unless otherwise specified)
1.8
2
2.2
–
1
–
–
200
–
–
70
–
MHz
MHz
kHz
ns
Input Voltage Level Low
Input Voltage Level High
Input Leakage Current (APWM, EN,
PWM, and SKIP pins)
VIL
VIH
IIleak
VI(pin) = 5 V, TA = 25°C
–
–
0.4
V
1.5
–
–
V
–
–
100
µA
Input Leakage Current (SELx pins)
Over Voltage Protection (OVP)
ISELleak
–
–
1
µA
Output Overvoltage Rising Limit
OVP Sense Current
OVP Release Current
OVP Leakage Current
Boost Switch
VOVP
IOVPH
IOVPL
IOVPleak
VVOP = 21 V
28
–
32
V
–
54.9
–
µA
–
47.8
–
µA
–
0.1
–
µA
Switch On Resistance
Switch Leakage Current
Switch Current Limit
Rds(on)
ISWleak
ISWlim
ISW = 1.5 A
VSW = 5 V, TA = 25°C
VSW = 21 V
–
225
–
mΩ
–
–
1
µA
–
1
–
µA
1.8
2
–
A
Continued on the next page…
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com