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AME, Inc.
AT9173 Bus Termination Regulator
n General Description
The AT9173 is a voltage regulator which could convert the input voltage ranging from 1.8V to 5V to an output voltage that user settled. The regulator can provide sourcing or sinking current.The AT9173, used in conjunction with series termination resistors, provides an excellent voltage source for active termination schemes of high speed transmission lines as those seen in high speed memory buses and distributed backplane designs. The voltage output of the regulator can be used as a termination voltage for DDR SDRAM. Current limits in both sourcing and sinking mode, plus on-chip thermal shutdown make the circuit tolerant of the output fault conditions.
n Features
Support Both DDR I (1.25VTT) and DDR II
(0.9VTT) Requirements Capable of Sourcing and Sinking Current Current-limiting Protection Thermal Protection Integrated Power MOSFETs Generates Termination Voltages for SSTL-2 High Accuracy Output Voltage at Full-Load Adjustable VOUT by External Resistors Minimum External Components Shutdown for Standby or Suspend Mode Operation with High-impedance Output
n Applications DDRI/DDRII Memory Termination Supply
Active Termination Buses Desktop PC,NoTebook,Server and workstation Graphic Card Set Top Box Embedded System
n Typical Application
DDR _2.5 V AT9173 A-SOP 8 VCC_ 3.3 V
1 R2 100KO C4 0.1 uF C2 470uF 2 3 4
VIN GND REFEN VOUT
VCNTL VCNTL
8 7
VCNTL VCNTL
6 5 DDR_VTT 1.25V/1.5A
R4 100KO
AT9173A SOP-8
C8 4.7uF
C6 470uF
Rev. C.04
1
AME, Inc.
AT9173 Bus Termination Regulator
n Typical Application(Contd.)
VCC_ 3.3V
DDR_2.5V
AT9173 E-SOP 8 / PP VIN 1 NC GND _PAD NC VCNTL NC 5
8 7 6 DDR_ VTT 1 .25V/2A
R1 100 KO
C3 0.1uF
C4 470uF
GND 2 REFEN 3 4 VOUTL
R3 100KO
AT9173E SOP-8/PP
C7 4.7uF
C5 470uF
n Function Block Diagram
VCNTL VIN
Thermal Sensor + Thermal & Over Current Protection Circuit REFEN + GND VOUT
VCNTL
2
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Pin Configuration
SOP- 8 Top View
8 7 6 5
SOP- 8/PP Top View
AT9173A 1. IN 2. GND 3. REFEN 4. OUT 5. VCNTL 6. VCNTL 7. VCNTL 8. VCNTL
8 7 6 5
AT9173
1 2 3 4
AT9173
1 2 3 4
AT9173E 1. IN 2. GND 3. REFEN 4. OUT 5. NC 6. VCNTL 7. NC 8. NC
n Pin Description
Pin name Pin Description
Input voltage pin which supplies current to the V OUT pin. Connect this pin to a welldecoupled voltage to prevent the input rail from dropping during large load transient. A large and low ESR capacitor is recommended to use that should be placed as close as possible to the V IN pin. Ground pin. Tie directly to ground plance. Voltage control pin which supplies the internal control circuitry and provides the drive voltage. The driving capability of output current is proportioned to the VCNTL. Connect this pin to 5V bias supply to handle large output current with at least 1uF capacitor from this pin to GND. An important note is that VIN should be kept lower or equal to VCNTL. Reference voltage input and active low shutdown control pin. Two resistors dividing down the VIN voltage on this pin to create the regulatedoutput voltage. Pulling this pin to GND to turn off the device by an open-drain, such as 2N7002 N-Channel MOSFET. Regulator output. V OUT is regulated from REFEN voltage that is used to terminate the bus resistors. It is capable of sinking and sourcing current while regulating the output rail. To maintain adequate large signal transient response, typical value of 1000uF electrolytic capacitor with 10uF ceramic capacitors are recommended to reduce the effects of current transients on VOUT. No Connection. Not internal connected. Connected to GND plance for better heat dissipation.
IN
GND
VCNTL
REFEN
OUT
NC* GND Pad*
* By SOP-8/PP only
Rev. C.04 3
AME, Inc.
AT9173 Bus Termination Regulator
n Ordering Information
Part Number
AT9173AG
Marking
AT9173AG yyww* AB xxxxxxx##** AT9173EG yyww* AC xxxxxxx##**
Output Voltage
ADJ
Package
SOP-8
Operating Temp. Range
-25 C to +85 C AT9173EG ADJ SOP-8/PP
o
o
Note: * yy and ww represents the data code. ** XXXXXXX represents the wafer lot number, ## represents the wafer number
4
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Absolute Maximum Ratings
Parameter
Input Voltage. V IN to GND VCNTL to GND ESD Rating (Human Body Mode) Storage Temperature Lead Temperature (Soldering. 5sec)
Symbol
VIN VCNTL VESD TSTG TL
Maximum
6 6 2 150 245
Unit
V V KV
O O
C C
n Recommended Operating Conditions
Parameter
Supply Voltage 1 Supply Voltage 2 Output Current of V OUT Pin * Junction Temperature
Symbol
VIN VCNTL *IOUT TJ
Rating
1.8 or 2.5 3.3 -2 to 2 -25 to 125
Unit
V V A
O
C
*The symbol "+" means the VOUT sources current to load; the symbol "-" means the VOUT sinks current to GND
n Thermal Characteristics
Parameter
Thermal Resistance* (Junction to Case)
Package
SOP-8 SOP-8/PP SOP-8 SOP-8/PP SOP-8
Die Attch
Non-Conductive Epoxy Conductive Epoxy Non-Conductive Epoxy Conductive Epoxy Non-Conductive Epoxy Conductive Epoxy
Symbol Maximum
55 JC 19
Unit
O
C/W
Thermal Resistance (Junction to Ambient)
120 JA 84 1300 PD 1450 mW
Internal Power Dissipation SOP-8/PP
Rev. C.04
5
AME, Inc.
AT9173 Bus Termination Regulator
n Electrical Specifications
Limits in standard typeface are for TA=25J , unless otherwise specified: VIN=2.5V, VCNTL=3.3V, VREFEN =0.5V IN.
Parameter Output Offset Voltage Load Regulation (DDR 1/2) Input Voltage Range (DDR 1/2) Operating Current of VCNTL Current In Shutdown Mode Short Circuit Protection SOP-8 Current Limit PSOP-8 Current Limit Over Temperature Protection Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Symbol VOS VLOAD VIN V CNTL ICNTL ISHDN ILIMIT ILIMIT
Test Condition I OUT=0A (Note 1) I L=0~1.5A (Fig 4) I L=0~-1.5A KEEP VCNTL VIN on operation power on and power off No Load VREFEN < 0.2V, RL=180 (Fig 5)
Min -20 -20 -20 1.6 2.5
Typ 0 0 0 2.5/1.8 3.3 1.4 25.6
Max 20 20 20 4 6
Units mV mV
V mA A
Fig 6,7 Fig 6,7
2.1 2.4
A A
TSD
3.3V
VCNTL 5 V
125
O
C
Guaranteed by design
30
Note1: VOS offset is the voltage measurement defined as VOUT subtracted from VREFEN .
6
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Application Information
VCNTL = 3.3V VIN = 1.8V
RTT CIN CCNTL
R1
VIN REFEN
VCNTL
2N7002 EN
AT9173
GND
VOUT
R2
CSS
COUT
RDUMMY
R 1 = R2 = 100KO, RTT = 50O / 33O / 25O C OUT(MIN) = 10uF (Ceramic) + 1000uF under the worst case testing condition R DUMMY = 1KO as for VOUT discharge when V IN is not presented but VCNTL is presented C SS = 1uF, CIN = 470uF (Low ESR), C CNTL = 47uF
n Application Circuit
Typical application circuit is used as a regulator to provide termination voltage in double data rate (DDR) memory system. The regulator could source and sink up to 2A peak current. The output voltage will follow REFEN which generated by two external dividing resistors down from VIN or to the desired output voltage set externally by forcing a voltage level to REFEN pin. To add a shutdown function , connect a small transistor to REFEN pin. To perform shutdown function , put a logic high 5V signal to EN yield a low (0V) to REFEN pin thus force output voltage to zero voltage. The capacitor Css is used to softstart the output voltage since V OUT will follow REFEN. Time constant for this circuit is Css*(R1//R2). The Css could also used as the bypass capacitor to filter out noise in REFEN pin. So carefully layout should put Css close to REFEN pin to maintain noise immunity. The C IN an C CNTL is used as power decoupling capacitor. COUT is composed of 10uF ceramic plus 1000uF electrolyte capacitors. The first one is to used as high frequency filter and the second one is used to reduce voltage drop during load regulating.
n General Regulator
The AT9173 can be used as a general regulator. To get a desired output voltage, put a reference voltage to REFEN pin or dividing resistors down a input voltage source. To drive inside N-Channel MOSFET the VCNTL should be larger than VIN to get enough driving voltage. The minimum dropout voltage could be IOUT *0.1, where IOUT is the output current.
n Layout issue
Place a bypass capacitor as close as possible to VIN and VCNTL pin is necessary. A low ESR capacitor is recommended for this bypass capacitor. Use wide and short PCB traces to connect in between VIN power source VOUT to reduce PCB resistance thus to reduce undesired power dissipation.
Rev. C.04
7
AME, Inc.
AT9173 Bus Termination Regulator
n Thermal issue
AT9173 has a internal thermal protection to protect the device at any overload conditions. For safety reason the operation junction temperature should not exceed 125 J. The dissipation of the device is
PD = (V IN - V OUT ) xI OUT
And also the maximum power dissipation is
PD , MAX = (T J , MAX - T A ) / JA
Where Tj,max is the maximum operation junction 125 degree C, Ta is the ambient temperature and the is JA the junction to ambient thermal resistance. The junction to ambient thermal resistance is 70 J /W for exposed pad SOP-8 package. It can be dramatically reduced by placing a large area PCB trace under exposed pad to emit heat generated by the die attached to the exposed pad.
8
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Test Circuit
Fig 4: Output Voltage Tolerance, VOUT
Fig 5: Current in Shutdown Mode, ISHDN
Rev. C.04
9
AME, Inc.
AT9173 Bus Termination Regulator
Figure 6: Current Limit for High Side, ICLHIGH
Figure 7: Current Limit for Low Side, ICLLOW
10
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Typical Characteristics
Rev. C.04
11
AME, Inc.
AT9173 Bus Termination Regulator
n Operation Waveforms DDR1 Load Transient Response
VIN=2.5V, VCNTL=3.3V VREF is 1.25V supplied by a regulator COUT=1000uF/35V IOUT slew rate = +-0.25A/mS
+ 0 A/ + 1.5 A/ + 0 A
+ 0 A/ + 2 A / + 0 A
+ 0 A/ + 2.5 A/ + 0 A
Ch1= IOUT ,Ch4 = VOUT
Ch1= I OUT ,Ch4 = VOUT
Ch1= I OUT ,Ch4 = VOUT
Load Transient Response
VIN=2.5V, VCNTL=3.3V VREF is 1.25V supplied by a regulator COUT=1000uF/35V IOUT slew rate = +-0.25A/mS
- 0 A/ - 1.5 A/ - 0 A
- 0 A / - 2 A/ - 0 A
- 0 A/ - 2.5 A - 0 A /
Ch1= IOUT ,Ch4 = VOUT
Ch1= I OUT ,Ch4 = VOUT
Ch1= IOUT ,Ch4 = VOUT
12
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Operation Waveforms DDR2 Load Transient Response
VIN=1.8V, VCNTL=3.3V VREF is 0.9V supplied by a regulator COUT=1000uF/35V IOUT slew rate = +-0.25A/mS
+ 0 A / + 1.5 A/ + 0 A
+ 0 A/ + 2 A/ + 0 A
Ch1= V OUT, Ch4= IOUT
Ch1= VOUT ,Ch4= IOUT
Load Transient Response
VIN=1.8V, VCNTL=3.3V VREF is 0.9V supplied by a regulator COUT=1000uF/35V IOUT slew rate = +-0.25A/mS
- 0 A/ - 1.5 A - 0 A /
- 0 A / - 2 A/ - 0 A
Ch1= VOUT , Ch4 = IOUT
Ch1= VOUT , Ch4 = IOUT
Rev. C.04
13
AME, Inc.
AT9173 Bus Termination Regulator
n Date Code Rule
Marking A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A Date Code W W W W W W W W W W W W W W W W W W W W Year xxx0 xxx1 xxx2 xxx3 xxx4 xxx5 xxx6 xxx7 xxx8 xxx9
n Tape and Reel Dimension
SOP- 8
P
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package SOP-8
Carrier Width (W) 12.00.1 mm
Pitch (P) 4.00.1 mm
Part Per Full Reel 2500pcs
Reel Size 3301 mm
14
Rev. C.04
AME, Inc.
AT9173 Bus Termination Regulator
n Tape and Reel Dimension
SOP- 8/PP
P
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package SOP-8/PP
Carrier Width (W) 12.00.1 mm
Pitch (P) 4.00.1 mm
Part Per Full Reel 2500pcs
Reel Size 3301 mm
Rev. C.04
15
AME, Inc.
AT9173 Bus Termination Regulator
n Package Dimension
SOP-8
Top View C Side View
SYMBOLS A
MILLIMETERS MIN
1.35 0.10 0.33 0.19 4.80 3.80 0.40 5.80 0
o
INCHES MIN
0.05315 0.00394 0.01299 0.00748 0.18898 0.14961
MAX
1.75 0.30 0.51 0.25 5.33 4.00 1.27 6.30 0.10 8
o
MAX
0.0689 0.01181 0.02008 0.00984 0.20984 0.15748
H
E
A1 A2 B C
1.473 REF
0.05799 REF
D
L c
D E e L H
Front View
7 (4X)
o
1.27 BSC
0.05000 BSC 0.01575 0.05000 0.22835 0.24803 0
o
A2
y
0.00394 8
o
B
SOP-8/PP
Top View D1 Side View c
A1
e
A
SYMBOLS A
MILLIMETERS MIN
0 1.350 0.100 3.750 5.700 0.300 0.310 4.720
INCHES MIN
0 0.053 0.004 0.148 0.224 0.012 0.012 0.186
MAX
1.750 0.150 1.600 0.250 4.150 6.300 0.900 0.510 5.120
MAX
0.069 0.006 0.063 0.010 0.163 0.248 0.035 0.020 0.202
E1 E2 E L1 C
1
A1 A2 C E E1 L b D
Front View D A2
A
e E2 D1
1.270 BSC 0
o
0.05 BSC
o
A1
b
e
8
0
o
8
o
2.150 2.150
2.500 3.400
0.085 0.085
0.098 0.134
16
Rev. C.04
www.ame.com.tw
E-Mail: sales@ame.com.tw
Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. (c) AME, Inc. , December 2007 Document: ATT-DS9173-C.04
Corporate Headquarter
AME, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989
U.S.A (Subsidiary)
Analog Microelectronics, Inc.
3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2046 Tel : (408) 988-2388 Fax: (408) 988-2489

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