8283
PRELIMINARY INFORMATION
(Subject to change without notice)
November 21, 2000
LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR
Intended for analog and digital satellite receivers, the low-noise block
converter regulator (LNBR) is a monolithic linear and switching voltage
regulator designed to provide power and interface signals to the LNB down
converter via the coaxial cable. If the device is in stand-by mode (EN terminal
LOW), the regulator output is disabled, allowing the antenna downconverters to
be supplied or controlled by other satellite receivers sharing the same coaxial
cable. Similar two-output LNB supply and control voltage regulators are the
A8284SB/SLB.
For slave operation in single-dish dual-receiver systems, the bypass
function is implemented by an electronic switch between the master input
terminal (MI) and the LNB terminal, leaving all LNB power and control
functions to the master receiver. This electronic switch is closed if the device
is powered, EN is HIGH, and OSEL is LOW.
The regulator outputs are set to 12, 13, 18, or 20 V by the VSEL terminals.
Additionally, it is possible to increase the selected voltage by 1 V to compen-
sate for the voltage drop in the coaxial cable (LLC terminal HIGH). The
LNBR combines a tracking switching regulator and low-noise linear regulator.
Logic inputs (VSEL0, VSEL1, and LLC) select the desired output voltage. A
tracking current-mode buck converter provides the linear regulator with an
input voltage that is set to the output voltage plus typically 0.8 V. This main-
tains constant voltage drop across the linear regulator while permitting ad-
equate voltage range for tone injection.
The device is supplied in a 24-pin plastic DIP with batwing tabs
(A8283SB), or a 24-lead SOIC power-tab package (A8283SLB). In both cases,
the power tab is at ground potential and needs no electrical isolation.
Data Sheet
27448
A8283SLB
OSEL
OLF
VBULK
MIOUT
MI
GND
GND
SENSE
LNB
LX
VIN
TCAP
1
2
3
24
23
22
EXTM
VINT
PUMPX
VPUMP
CPUMP
GND
GND
ENT
EN
VSEL0
VSEL1
LLC
4
5
6
7
8
9
9
10
11
12
BUCK
REG.
CHARGE
PUMP
VOLTAGE
CONTROL
21
20
19
18
17
16
15
14
13
Dwg. PP-072A
Note that the A8283SB (dual in-line package)
and A8283SLB (small-outline IC package) are
electrically identical and share a common
terminal number assignment.
FEATURES
I
I
I
I
I
I
I
I
I
I
Short-Circuit Protected Bypass Function for Slave Operation
LNB Selection and Stand-By Function
Built-In Tone Oscillator Factory Trimmed to 22 kHz, Facilitates
DiSEqC鈩?(a trademark of EUTELSAT) Encoding
Full Modulation With No Load
Tracking Switch-Mode Power Converter for Lowest Dissipation
Externally Adjustable Short-Circuit Protection
LNB Short-Circuit Protection and Diagnostics
Auxiliary Modulation Input
Cable Length Compensation
Internal Over-Temperature Protection
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
IN
..........................
47 V
Output Current, I
O
....
Internally Limited
Logic Input Voltage Range,
V
I
...................................
-0.5 V to +7 V
Bypass Switch Current,
I
SW
........................
Internally Limited
Flag Output Voltage, V
OLF
..................
7 V
Operating Temperature Range,
T
A
...............................
-20
擄
C to +85
擄
C
Storage Temperature Range,
T
S
.............................
-40
擄
C to +150
擄
C
This device incorporates features that have patents pending.
Always order by complete part number, e.g.,
A8283SLB
.
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