A8500EECTR-T Allegro Microsystems Inc, A8500EECTR-T Datasheet
A8500EECTR-T
Specifications of A8500EECTR-T
Related parts for A8500EECTR-T
A8500EECTR-T Summary of contents
Page 1
Flexible WLED/RGB Backlight Driver for Medium Size LCDs Features and Benefits ▪ Active current sharing between LED strings for ±1.5% typical current matching and ±1.2% typical accuracy ▪ Drive series × 8 parallel = 96 LEDs (V ...
Page 2
... A8500 Selection Guide Part Number Ambient Temperature, T A8500EECTR-T A8500GECTR-T *Contact Allegro for additional packing options Device package is lead (Pb) free, with 100% matte tin leadframe plating. Absolute Maximum Ratings Characteristic SW and OVP Pins LED1 through LED8 Pins VIN Pin Remaining Pins Operating Ambient Temperature ...
Page 3
A8500 ±10 VIN COMP C C Reference and Soft Start SKIP FSET 100 kΩ R FSET AGND EN 100 kΩ Serial Interface SEL1 PWM Generator SEL2 SEL3 PWM 100 kΩ ISET Amp R ISET ...
Page 4
A8500 ELECTRICAL CHARACTERISTICS, valid at T Characteristics Input Voltage Range Undervoltage Lockout Threshold UVLO Hysteresis Window Supply Current APWM Frequency Range Error Amplifier Error Amplifier Open Loop Gain Error Amplifier Unity Gain Bandwidth Error Amplifier Transconductance Error Amplifier Output Sink ...
Page 5
A8500 ELECTRICAL CHARACTERISTICS (continued), valid at T otherwise noted Characteristics LED Current Sinks LEDx Regulation Voltage Current Gain SET LEDx Voltage on ISET Pin I Allowable Current Range SET LEDx Accuracy LEDx Matching LEDx Switch Leakage Current ...
Page 6
A8500 Efficiency with EN dimming is similar to that with APWM dimming. APWM light load efficiency can be improved by reducing boost switching frequency with SKIP set high. PWM Efficiency ch. with 7 LEDs per ...
Page 7
A8500 EN Pin Turn ch., 8 LEDs per ch. IN BAT Symbol Parameter Units/Division OUT C3 V OUT time ...
Page 8
A8500 The A8500 is a multioutput WLED driver for medium display backlighting. The A8500 works with 4.2 to 5.5 V input supply, and it has an integrated boost converter to boost battery voltage ...
Page 9
A8500 This current is multiplied internally with a gain of 210, and then mirrored on all enabled LEDx pins. This sets the maximum cur- rent through the LEDs, referred to as “100% current.” The effects of the value of R ...
Page 10
A8500 To indicate the end of a programming sequence, set the EN pin high for a period which is either (a) greater than 256 oscil- HID lator periods when the SKIP pin is high, or (b) greater than ...
Page 11
A8500 At startup, the output capacitor is discharged and the IC enters soft start. The boost current is limited and all active LEDx 1 pins sink / of the set 100% current until all of the enabled ...
Page 12
A8500 Calculate the value for R as follows: OVP – 30) / 54.9 μA , OVP OVP where V is the desired typical OVP level in V, and R OVP in Ω. For tighter OVP limits, a ...
Page 13
A8500 A typical application circuit for dimming an LCD monitor backlight with 96 LEDs is shown in figure 1. Figure 12 shows two dimming methods: digital PWM control (PWM signal on the PWM pin) and analog PWM control, with the ...
Page 14
A8500 C C RISET Figure 15. Typical application circuit for PWM dimming, using digital PWM (on the PWM pin, with APWM high). Showing configuration of 16 WLEDs at 100 mA, in two strings of 8 LEDs each ...
Page 15
A8500 Terminal List Table Number Name 1 PGND Power ground pin. Reduces boost switching frequency in case of light load to improve frequency. Normally, this pin should be low; when 2 SKIP high divided ...
Page 16
A8500 (Top View) D 27X 0.08 C 0.20 0.40 0. (Bottom View) Copyright ©2006-2010, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. patents pending. ...