8281
AND
8282
LNB SUPPLY AND
CONTROL-VOLTAGE REGULATORS
11
www.allegromicro.com
A8281SLB A8282SLB
Terminal Terminal Terminal
Name Number Number Terminal Description
NC – 1 No (internal) connection
OLF 2 2 Overload flag output: low (fault) when I
LNB
> I
LNBM
or
T
J
> 165°C, high when I
LNB
< I
LNBM
and T
J
< 130°C
VBULK 3 3 Tracking supply voltage to linear regulator
NC – 4, 5 No (internal) connection
GND 4 6, 7 Ground and substrate
SENSE 5 8 Current limit setup resistor
LNB 6 9 Output voltage to LNB
LX 7 10 Inductor drive point
VIN 8 11 Supply input voltage (minimum, V
LNB
+ 2.5-V)
TCAP 9 12 Capacitor for setting the rise and fall time of the outputs for
line-length compensation
LLC – 13 Logic input: output voltage select
VSEL1 10 14 Logic input: output voltage select
VSEL0 – 15 Logic input: output voltage select
EN 11 16 Logic input: when high, enables device
ENT 12 17 Logic input: when high, enables internal 22-kHz modulation
GND 13 18, 19 Ground and substrate
CPUMP 14 20 High side of charge-pump capacitor
VPUMP 15 21 Gate-supply voltage for high-side drivers
PUMPX 16 22 Charge-pump drive
VINT – 23 Bypass capacitor for internal voltage reference
EXTM 1 24 External modulation input
Terminal List
