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8284
ADVANCE INFORMATION
(Subject to change without notice) December 22, 2000
TWO-OUTPUT 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 downconverter via the coaxial cable. Because most satellite receivers have two antenna ports, the output voltage of the regulator is available at one of two logic-selectable output terminals (LNBA, LNBB). If the device is in stand-by mode (EN terminal LOW), both regulator outputs are disabled, allowing the antenna downconverters to be supplied and controlled by other satellite receivers sharing the same coaxial cable. Similar single-output devices, with a bypass function for slave operation in single-dish dual-receiver systems, are the A8283SB/SLB. 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 compensate for the voltage drop in the coaxial cable (LLC terminal HIGH). The LNBR combines a tracking switching regulator and low-noise linear regulators. Logic inputs (VSEL0, VSEL1, and LLC) select the desired output voltage. A tracking current-mode buck converter provides the linear regulator input voltage that is set to the output voltage plus typically 0.8 V. This maintains constant voltage drop across the linear regulators while permitting adequate voltage range for tone injection. The device is supplied in a 24-pin plastic DIP with batwing tabs (A8284SB), or a 24-lead SOIC power-tab package (A8284SLB). In both cases, the power tab is at ground potential and needs no electrical isolation.
Data Sheet 27448.1
A8284SLB
OSEL OLF VBULK LNBB NC GND GND SENSE LNBA LX VIN TCAP 1 2 3 4 5 6 7 8 9 9 10 11 12 BUCK REG. 24 23 22 EXTM VINT PUMPX VPUMP CPUMP GND GND ENT EN VSEL0 VSEL1 LLC
21 20 19 18 17 16 15 14
Note that the A8284SB (dual in-line package) and A8284SLB (small-outline IC package) are electrically identical and share a common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VIN .......................... 47 V Output Current, IO .... Internally Limited Logic Input Voltage Range, VI ................................... -0.5 V to +7 V Flag Output Voltage, VOLF .................. 7 V Operating Temperature Range, TA ............................... -20C to +85C Storage Temperature Range, TS ............................. -40C to +150C
T C A T N O C
13
Dwg. PP-072-1A
Y R O T C A F
VOLTAGE CONTROL
CHARGE PUMP
FEATURES
I I I I I I I I I I Complete Interface for Two LNBs Remote Supply and Control LNB Selection and Stand-By Function Built-In Tone Oscillator Factory Trimmed to 22 kHz, Facilitates DiSEqCTM (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
This device incorporates features that have patents pending.
Always order by complete part number, e.g., A8284SLB .
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
FUNCTIONAL BLOCK DIAGRAM
RS
CPUMP PUMPX VPUMP SENSE VBULK
47 V MAX
VIN LX
+
VINT
VOLTAGE REG.
CHARGE PUMP
BOOST VOLTAGE
EN
- 5V 176 kHz +
BUCK CONV. 7V VREF
- + OVERCURRENT - + 800 mV + 1 0 5 k 150 mV LNBB
/2 ENT
352 kHz 25 k
- +
/8 & WAVESHAPING
22 kHz TONE 5 k 1 k
TSD OLF OVER-CURRENT
VSEL1
VSEL0
OSEL
LLC
TCAP
OSEL VSEL0 L L L L L L L L H H H H H H H H L L L L H H H H L L L L H H H H
VSEL1 L L H H L L H H L L H H L L H H
LLC L H L H L H L H L H L H L H L H
VLNBA(typ) 13 V 14 V 18 V 19 V 12 V 13 V 20 V 21 V Low Low Low Low Low Low Low Low
VLNBB(typ) Low Low Low Low Low Low Low Low 13 V 14 V 18 V 19 V 12 V 13 V 20 V 21 V
Output Voltage Select Table
2
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 2000, Allegro MicroSystems, Inc.
-
EXTM
LNBA
Dwg. FP-051
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
ELECTRICAL CHARACTERISTICS at TA = 25C, OSEL = H for LNBB, OSEL = L for LNBA (each output tested separately), ENT = L, EN = H, LLC = L, VIN = 24 V, IO = 50 mA (unless otherwise noted).
Limits Characteristic Supply Voltage Output Voltage Symbol VIN VO Test Conditions IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = L IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = L IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = H IO = 600 mA, VSEL0 = L, VSEL1 = H, LLC = L IO = 600 mA, VSEL0 = L, VSEL1 = H, LLC = H IO = 600 mA, VSEL0 = H, VSEL1 = L, LLC = L IO = 600 mA, VSEL0 = H, VSEL1 = L, LLC = H IO = 600 mA, VSEL0 = H, VSEL1 = H, LLC = L IO = 600 mA, VSEL0 = H, VSEL1 = H, LLC = H Line Regulation VO VO VOM(th) ftone Vtone(PP) dctone t r, t f Gmod Vmod(PP) Zmod ENT = H ENT = H ENT = H ENT = H VO/Vmod, f = 10 Hz to 40 kHz AC coupling VO = 13 V, VI = 16 to 40 V VO = 18 V, VI = 21 to 40 V Load Regulation Current-Limiting Threshold Tone Frequency Tone Amplitude Tone Duty Cycle Tone Rise or Fall Time External Modulation Gain External Modulation Input Voltage External Modulation Impedance VO = 13 or 18 V, IO = 50 to 600 mA Min. Typ. Max. Units V V V V V V V V V mV mV mV mV kHz mV % s V/V mV -- 3.3 + VBUCK 47 12.5 13.4 17.3 18.2 11.5 12.5 19.2 20.2 -- -- -- 125 20 550 40 5.0 -- -- 13 14 18 19 12 13 20 21 4.0 4.0 80 135 22 680 50 10 5.0 -- 13.5 14.6 18.7 19.8 12.5 13.5 20.8 21.8 40 40 180 145 24 800 60 15 -- 160
f = 10 Hz to 40 kHz
--
5.0
--
k
continued next page ...
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8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
ELECTRICAL CHARACTERISTICS at TA = 25C, ENT = L, EN = H, LLC = L, VIN = 24 V, IOUT = 50 mA (unless otherwise noted).
Limits Characteristic Overload Flag Logic Low Overload Flag Leakage Current Logic Input Voltage Symbol VOL IOZ VIL VIH Logic Input Current Supply Current IIH IIN VIH = 5 V Outputs disabled (EN = L) ENT = H, IO = 600 mA, VO = 13 V Thermal Shutdown Temp. Linear Regulator Voltage Drop Switching Frequency TJ VBUCK fO VBULK - VO 16 * ftone Test Conditions IOL = 8 mA VOH = 5.5 V Min. -- -- Typ. 0.28 <1.0 Max. -- -- Units V A
-- 2.0 -- -- -- -- -- 320
-- -- <1.0 0.5 382 165 0.8 352
0.8 -- -- -- -- -- -- 384
V V A mA mA C V kHz
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
FUNCTIONAL DESCRIPTION
The ENT (Tone Enable) terminal activates the internal tone signal, modulating the dc output with a 0.3 V, 22 kHz symmetrical waveform. The internal oscillator is factory trimmed to provide a tone of 22 kHz 2 kHz. No further adjustment is required. The internal oscillator operates the buck converter at 16 times the tone frequency. Burst coding of the 22 kHz tone can be accomplished, due to the fast response of the ENT input and rapid tone response. This allows implementation of the DiSEqCTM protocols. To improve design flexibility and to allow implementation of proposed LNB remote control standards, an analog modulation input terminal is available (EXTM). An appropriate dc blocking capacitor must be used to couple the modulating signal source to the EXTM terminal. If external modulation is not used, the EXTM terminal can be left open. The output linear regulators will sink and source current. This feature allows full modulation capability into capacitive loads as high as 0.25 F. The programmed output voltage rise and fall times can be set by an internal 25 k resistor and an external capacitor located on the TCAP terminal. Although any value of capacitor is permitted, practical values are typically 0.001 F to 0.02 F. This feature only affects the turn on and programmed voltage rise and fall times. Modulation is unaffected by the choice of TCAP. This terminal can be left open if voltage rise and fall time control is not required. Two terminals are dedicated to the over-current protection/monitoring: SENSE and OLF. The LNB output is current limited. The short-circuit protection threshold is set by the value of an external resistor, RS, between terminals 3 and 8. RS = VOM(th)/IOM where VOM(th) is the current-limiting threshold voltage and IOM is the desired current limit value. The minimum recommended value for RS is 0.17 .
In operation, the short-circuit protection produces current fold-back at the input due to the tracking converter. If the output is shorted the linear regulator will limit the output current to IOM. The tracking converter will maintain a constant voltage drop of 0.8 V across the linear regulator. This condition results in typically 550 mW dissipation (IOM * 0.8 V). Short-circuit or thermal shutdown activation will cause the OLF terminal, an opendrain diagnostic output flag, to go LOW. Thermal resistance: DIP -- RJA = 40C/W, RJT = 6C/W, SOIC -- RJA = 55C/W, RJT = 6C/W. The device junction temperature should be kept below 150C. Thermal shut-down circuitry turns off the device if junction temperature exceeds +165C typically.
The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use.
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5
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
Terminal Configuration Symbol
OSEL OLF VBULK LNBB NC GND SENSE LNBA LX VIN TCAP LLC VSEL1 VSEL0 EN ENT GND CPUMP VPUMP PUMPX VINT EXTM
Terminal
1 2 3 4 5 6, 7 8 9 10 11 12 13 14 15 16 17 18, 19 20 21 22 23 24
Function
Logic input: selects between LNBA (when low) and LNBB (when high) Overload flag output: low when IO > IOM or TJ > 165C, high when IO < IOM and TJ < 130C Tracking supply voltage to linear regulators Output voltage to LNBB No (internal) connection Ground Current limit setup resistor Output voltage to LNBA Inductor drive point Supply input voltage (minimum, VLNB + 2.5 V) Capacitor for setting the rise and fall time of the outputs Logic input: when high, increases output voltage by 1 V for line length compensation Logic input: output voltage select Logic input: output voltage select Logic input: when high, enables device (LNB on) Logic input: when high, enables internal 22 kHz modulation Ground High side of charge-pump capacitor Gate supply voltage for high-side drivers Charge-pump drive Bypass capacitor for internal voltage reference External modulation input
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
A8284SB
Dimensions in Inches (controlling dimensions)
0.014 0.008
24
NOTE 1
13
0.430 0.280 0.240
MAX
0.300
BSC
1
0.070 0.045
6
7 1.280 1.230
0.100
BSC
12
0.005
MIN
0.210
MAX
0.015
MIN
0.150 0.115 0.022 0.014
Dwg. MA-001-25A in
Dimensions in Millimeters (for reference only)
24
NOTE 1
13
0.355 0.204
10.92 7.11 6.10
MAX
7.62
BSC
1
1.77 1.15
6
7 32.51 31.24
2.54
BSC
12
0.13
MIN
5.33
MAX
0.39
MIN
3.81 2.93 0.558 0.356
Dwg. MA-001-25A mm
NOTES: 1. 2. 3. 4.
Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece. Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative Lead thickness is measured at seating plane or below.
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7
8284 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
A8284SLB
Dimensions in Inches (for reference only)
24 13
0.0125 0.0091
0.2992 0.2914
0.491 0.394 0.050 0.016
0.020 0.013
1
2
3
0.6141 0.5985
0.050
BSC NOTE 1 NOTE 3
0 TO 8
0.0926 0.1043 0.0040 MIN.
Dimensions in Millimeters (controlling dimensions)
24 13
Dwg. MA-008-25 in
0.32 0.23
7.60 7.40
10.65 10.00 1.27 0.40
0.51 0.33
1
2
3
15.60 15.20
1.27
BSC NOTE 1 NOTE 3
0 TO 8
2.65 2.35 0.10 MIN.
NOTES: 1. Exact body and lead configuration at vendor's option within limits shown. 2. Lead spacing tolerance is non-cumulative 3. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
Dwg. MA-008-25A mm
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