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Rev 1; 2/06
LVD SCSI 27-Line Regulator
General Description
The DS2129 is a triple-output voltage regulator for 27-line, low-voltage-differential (LVD) SCSI termination for SPI-2 and SPI-3 applications using LVD termination networks. The device provides reference voltages and bias currents for LVD-termination resistor pi () networks. With a pi network (475, 121, 475), the DS2129 meets the common-mode bias, differential bias, and termination-impedance requirements of SPI-2 (Ultra2) and SPI-3 (Ultra3). The device also provides a 1.3V output for DIFFSENSE signaling, and includes protection features such as thermal shutdown and active current limiting. 2.7V to 5.25V Operation Differential Fail-Safe Bias
Features
Fully Compliant with SPI-2 and SPI-3
DS2129
Applications
SCSI Array Backplane SCSI Cables
PART* DS2129S
Ordering Information
VOLTAGE (V) 5 5 5 5 PINPACKAGE 16 SO 16 SO 16 SO 16 SO TOP MARK** DS2129 DS2129 DS2129 DS2129
Block Diagram
DS2129S+ DS2129S/T&R DS2129S+T&R
TERMPWR
PTAT BANDGAP (1.25V) REF125 THERMAL SHUTDOWN TS
+Denotes lead-free package. *All devices rated for the commercial (0C to +70C) temperature range. **A "+" anywhere on the topmark denotes a lead-free package.
DS2129
REFERENCES REF175 TS 1.75V REG1
Pin Configuration
TOP VIEW
REF130 TS
N.C. 1 TERMPWR 2
0.75V REG2
16 N.C. 15 N.C. 14 HS_GND
REG2 3 GND 4
DS2129
13 HS_GND 12 HS_GND 11 HS_GND 10 N.C. 9 N.C.
REF075
TS 1.3V DIFFSENSE
HS_GND 5 REG1 6 DIFFSENSE 7 N.C. 8
GND
SO (150 mils)
______________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
LVD SCSI 27-Line Regulator DS2129
ABSOLUTE MAXIMUM RATINGS
TERMPWR, DIFFSENSE, REG1, REG2 ....................-0.3V, +6.0V REG1, REG2 Continuous Output Current.......................200mA Continuous Power Dissipation (TA = +70C) 16-Pin SO (derate 13mW/C above +70C)........................1W Operating Temperature Range...............................0C to +70C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Soldering Temperature .......................................See IPC/JEDEC J-STD-020A Specification
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(TERMPWR = 3.3V, TA = 0C to +70C, unless otherwise noted.) (Note 1)
PARAMETER TERMPWR TERMPWR Supply Current TERMPWR Voltage VREF REGULATOR 0.75V Regulator Output Voltage, REG2 0.75V Regulator Source Current, REG2 0.75V Regulator Sink Current, REG2 0.75V Regulator Source Current Limit 0.75V Regulator Sink Current Limit 1.75V Regulator Output Voltage, REG1 1.75V Regulator Source Current, REG1 1.75V Regulator Sink Current, REG1 1.75V Regulator Source Current Limit 1.75V Regulator Sink Current Limit DIFFSENSE OUTPUT DIFFSENSE Driver Output Voltage DIFFSENSE Driver Source Current DIFFSENSE Driver Sink Current VDSO IDSH IDSL -5mA IDIFFSENSE 50A VDIFFSENSE = 0V VDIFFSENSE = 2.4V 1.2 -5 100 1.3 1.4 -15 200 V mA A V075 ISRC_075 ISINK_075 ISRCL_075 ISINKL_075 V175 ISRC_175 ISINK_175 ISRCL_175 ISINKL_175 IOUT = 125mA VOUT = 0.25V VOUT = 1.25V VOUT = 0V VOUT = 3.3V IOUT = 125mA VOUT = 1.25V VOUT = 2.25V VREF = 0V VREF = 3.3V +200 -700 +700 1.7 1.75 +200 -700 +700 1.8 -200 0.7 0.75 0.8 -200 V mA mA mA mA V mA mA mA mA ITERM VTERM No load 2.7 40 5.25 mA V SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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LVD SCSI 27-Line Regulator
ELECTRICAL CHARACTERISTICS (continued)
(TERMPWR = 3.3V, TA = 0C to +70C, unless otherwise noted.) (Note 1)
PARAMETER THERMAL SHUTDOWN Thermal-Shutdown Threshold (Note 2) Thermal-Shutdown Hysteresis (Note 2) For increasing temperature +150 10 C C SYMBOL CONDITIONS MIN TYP MAX UNITS
DS2129
Note 1: All voltages are referenced to ground. Note 2: Guaranteed by design and not production tested.
Typical Operating Circuit
TERMPWR 2.7V TO 5.25V TERMPWR 4.7F DIFFSENSE DIFFSENSE
DS2129
REG1 4.7F 475 1%
R1N
121 1%
R1P 4.7F 475 1% R2N
REG2
R26P
R27N 475 1%
121 1%
R27P 475 1%
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LVD SCSI 27-Line Regulator DS2129
Pin Description
PIN 1, 8, 9, 10, 15, 16 NAME FUNCTION
Chip Information
TRANSISTOR COUNT: 3778 CMOS and 80 BIPOLAR PROCESS: BiCMOS SUBSTRATE CONNECTED TO GROUND
N.C.
No Connection. Do not connect pins.
Thermal Information
Thermal Resistance (junction-to-ambient): JA = +77C/W Thermal Resistance (junction-to-case): JC = +25C/W
2
TERMPWR
Termination Power. Connect to SCSI TERMPWR line and decouple with a 4.7F ceramic capacitor. Regulator 2, 0.75V Output. Decouple with a 4.7F ceramic capacitor. Signal Ground Heat-Sink Ground. Internally connected to the mounting pad. Should be connected to ground. Regulator 1, 1.75V Output. Decouple with a 4.7F ceramic capacitor. DIFFSENSE Output. Drives the SCSI bus DIFFSENSE line.
3 4 5, 11-14
REG2 GND HS_GND
6 7
REG1 DIFFSENSE
Detailed Description
The DS2129 provides three regulated outputs. The REG1 provides a 1.75V output, and the REG2 provides a 0.75V output. Both regulators can sink and source 200mA of current. These regulators are current-limited to less than 700mA. The thermal-shutdown circuit disables the output buffers should the die temperature exceed +150C. With a pi network of resistors (475, 121, 475) connected to these two outputs, the DS2129 provides common-mode bias, differential bias, and common impedance and differential impedance, as required in a terminator specified in SPI-2 and SPI-3 standards for a SCSI system. The third regulator provides a 1.3V output for DIFFSENSE signaling.
4
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LVD SCSI 27-Line Regulator
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages).
SOICN .EPS
DS2129
INCHES DIM A A1 B C e E H L MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050
MILLIMETERS MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 1.27
N
E
H
VARIATIONS:
1
INCHES
MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC
TOP VIEW
DIM D D D
MIN 0.189 0.337 0.386
MAX 0.197 0.344 0.394
D A e B A1 L C
0-8
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL DOCUMENT CONTROL NO. REV.
21-0041
B
1 1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5 (c) 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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