CHAMP CM8500A 3a bus terminator Datasheet

CM8500A
3A BUS TERMINATOR
GENERAL DESCRIPTION
FEATURES
◆
Patent Filed #6,452,366
◆
pin PTSSOP and PSOP package
◆
Source and sink up to 3A, no heat sink required
◆
Peak Current to 6A
◆
Integrated Power MOSFETs
◆
Output voltage can be programmed by external resistors
default mode, when the VIN/2 pin is open, the output voltage
◆
Separate voltages for VCCQ and PVDD
is 50% of the VCCQ. The CM8500A can also be used to
◆
V OUT of ±3% or less at 3A
produce various user-defined voltages by forcing a voltage on
◆
Minimum external components
the VIN/2 pin. In this case, the output voltage follows the
◆
Shutdown for standby or suspend mode operation
◆
Thermal shutdown protection
◆
6A Low Noise Current Limit Protection
◆
External Soft Start
◆
Rail to Rail output Buck Converter
The CM8500A is a switching regulator designed to provide a
desired output voltage or termination voltage for various
applications by converting voltage supplies ranging from 2.0V
to 5.0V. The CM8500A can be implemented to produce
regulated output voltages in two different modes. In the
VIN/2 pin input voltage. The switching regulator is capable of
sourcing or sinking up to 3A of current while regulating an
output V TT voltage to within 3% or less.
The CM8500A, used in conjunction with series termination
resistors, provides an excellent voltage source for active
termination schemes of high speed transmission lines as
APPLICATIONS
those seen in high speed memory buses and distributed
backplane designs.
◆
Mother Board
The voltage output of the regulator can be used as a
◆
PCI / AGP Graphics
termination voltage for other bus interface standards such as
◆
Game / Play Station
SSTL, CMOS, Rambus ™ ,GTL+, VME, LV-CMOS, LV-TTL,
◆
Set Top Box
and PECL.
◆
IPC
◆
SCSI-III Bus terminator
◆
Buck Converter
PIN CONFIGURATION
PSOP-16 (PS16)/PTSSOP-16 (PT16)
Top View
2008/01/16
1
VCC 1
2
P V DD1
3
VL1
4
PG N D 1
PG N D 2
13
5
AG N D
AG N D
12
6
SD
VFB
11
7
VIN /2
VC CQ
10
8
AG SE N
AG N D
9
VC C2
16
PV D D 2
15
VL2
14
Champion Microelectronic Corporation
Page 1
CM8500A
3A BUS TERMINATOR
PIN DESCRIPTION
Pin No.
Symbol
Description
Operating Rating
Typ.
Max.
Min.
Unit
1,16
VCC1,VCC2
Voltage supply for internal circuits
2
2.5
5
V
2,15
PVDD1,PVDD2
Voltage supply for output power transistors
2
2.5
5
V
3,14
VL1,VL2
Output voltage/inductor connection
-3
3
A
0.75 X
VCC +
V
VCC
0.3V
0
VIN
V
(IDD1+IDD2, Output RMS current)
4,13
PGND1,PGND2
Ground for output power transistors
AGND
Ground for internal reference voltage divider
8
AGSEN
Ground for remote sensing
6
SD
Shutdown active high. CMOS input level
5,9,12
7
VIN/2
Input for external reference voltage
10
VCCQ
Voltage reference for external voltage divider
5
V
11
VFB
Feedback node for the VTT
5
V
BLOCK DIAGRAM
VCCQ
VCC1
10
1
PVDD1
2
SD
6
VCC2
16
PVDD2
15
OSCILLATOR/
RAMP GENERATOR
3
VL1
14
100K
7
AGND
5
AGND
9
Q
R
Q
VL2
ERROR AMP
VIN/2
S
+
+
RAMP AMP
COMPARATOR
-
100K
20PF
AGND12
8
AGND
4
PGND1
11
VFB
13
PGND2
ORDERING INFORMATION
Part Number
Temperature Range
CM8500AIT
-40℃ to 85
16-Pin
PTSSOP (PT16)
CM8500AIS
-40℃ to 85
16-Pin
PSOP (PS16)
CM8500AGIT*
-40℃ to 85
16-Pin
PTSSOP (PT16)
CM8500AGIS*
-40℃ to 85
16-Pin
PSOP (PS16)
CM8500ATEVAL
*Note: G : Suffix for Pb Free Product
2008/01/16
Champion Microelectronic Corporation
Package
Evaluation Board (T16)
Page 2
CM8500A
3A BUS TERMINATOR
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which the
Junction Temperature ...…………………… ……………150°C
device could be permanently damaged.
Storage Temperature
PVDD/VCC/VCCQ ......................................….......-0.3V to 6.0V
Lead Temperature (Soldering, 5 sec)………………….. 260°C
Voltage on Any Other Pin ………... GND – 0.3V to VCC + 0.3V
Thermal Resistance(θJA )….. …………..…………….. .40°C/W
……................……. -65°C to 125°C
Output RMS Current, Source or Sink .....…………........…...3.0A
OPERATING CONDITIONS
Temperature Range ............................. -40°C to 85°C
PVDD Operating Range .........................2.0V to 5.0V
ELECTRICAL
CHARACTERISTICS
(Unless otherwise stated, these specifications apply
TA=25°C; VCC=+3.3V and PVDD=+3.3V) maximum ratings are stress ratings only and functional device operation is not implied.(Note
1)
Symbol
Parameter
Test Conditions
CM8500A
Unit
Min.
Typ.
Max.
1.12
1.15
1.18
V
VCCQ = 2.5V
1.22
1.25
1.28
V
VCCQ = 2.7V
1.32
1.35
1.38
IOUT =
VCCQ = 2.3V
1.09
1.15
1.21
V
±3A,
VCCQ = 2.5V
1.19
1.25
1.31
V
VCCQ = 2.7V
1.28
1.35
1.42
V
VCCQ = 2.3V
1.139
1.15
1.162
V
VCCQ = 2.5V
1.238
1.25
1.263
V
VCCQ = 2.7V
1.337
1.35
1.364
V
KΩ
660
KHz
3
A
6
A
SWITCHING REGULATOR
IOUT = 0, VCCQ = 2.3V
VIN/2 =
open
Note 2
VL
Output Voltage, SSTL_2
V
VIN/2 =
open
Note 3
VIN/2
Internal Resistor Divider
IOUT = 0
Note 2
Note 2
VCCQ = 0
50
ZIN
VIN/2 Reference Pin Input Impedance
fsw
Switching Frequency
CM8500A
IOUT(RMS)
Maximum Output RMS Current
CM8500A
IOUT(PEAK)
Maximum Output Peak Current
CM8500A
Ilimit
Current limit
CM8500A
6
Drain to Source on-State Resistance
PVDD=5V
150
480
A
MOSFETs
RDS(ON)
180
mΩ
SUPPLY
IVCCA
Quiescent Current
IPVDD
VFB = 1.4V
LC unconnected
VFB = 1.4V
LC unconnected
200
µA
500
µA
Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions
Note 2: VCC, PVDD = 3.3V ±10%
Note 3: It’s not 100% test
2008/01/16
Champion Microelectronic Corporation
Page 3
CM8500A
3A BUS TERMINATOR
FUNCTIONAL DESCRIPTION
The CM8500A is a switching regulator that is capable of
Low Noise Current Limit:
sinking and sourcing 3A of current without an external heat
CM3708A’s current limit is a low noise current limit. It increase
sink.
CM8500A uses a standard surface mount PTSSOP
the system loop noise immunity while it is doing the current limit
and PSOP package with bottom metal exposed and the heat
protection for the system. The current limit is around 6A for the
can be piped through the bottom of the device and onto the
normal 3A operation.
PCB.
INPUTS
The CM8500A integrates power MOSFETs that are capable
The input voltage pins (VCCQ or VIN/2) determine the output
of source and sink 3A of current while maintaining excellent
voltages (VL1 or VL2). In the default mode, when the VIN/2 pin
voltage regulation. The output voltage can be regulated within
is open, the output voltage is 50% of the VCCQ input.
3% or less by using the external feedback. Separate voltage
If a specific voltage is forced at the VIN/2 pin, the output voltage
supply inputs have been added to fit applications with various
follows the voltage at the VIN/2 pin. VCCQ suggested
power supplies for the databus and power buses.
connecting to VCCQ of memory module for better tracking with
memory VCCQ.
VREF
The reference voltage could be ranged from 0V to VIN.
OTHER SUPPLY VOLTAGES
Several inputs are provided for the supply voltages: PVDD1,
OUPUTS
PVDD2, VCC1, and VCC2.
The output voltage pins (VL1, VL2) are tied to the databus,
address, or clock lines via an external inductor. Output voltage The PVDD1 and PVDD2 provide the power supply to the power
is determined by the VCCQ or VIN/2 inputs so it can be from
MOSFETs. VCC1 and VCC2 provide the voltage supply to the
0V to VIN..
logic section and internal error amplifiers.
Internal Power Switches:
FEEDBACK
CM3708A has been integrated 2 Power MOSFETs whose
The VFB pin is an input that can be used for closed loop
RDS(ON) is around 100m Ohm each.
compensation. This input is derived from the voltage output.
AGSEN pin is a contact node of internal resistor divider for
remote sense.
APPLICATIONS
USING THE CM8500A FOR SSTL BUS
TERMINATION
Figure 1 is the typical schematic of the CM8500ATEVAL that
Figure 4 shows the PCB layout of the CM8500ATEVAL.
shows the recommended approach for bus terminating
Table 1details the key parameters of SSTL_2 specification.
solutions for SSTL-2 bus. This circuit can be used in PC
Figure 5 shows two different approach of SSTL_2 Terminated
memory and Graphics memory applications as shown in
Output. (Refer to page 8 for detail description.)
Figure 2 and Figure 3.
2008/01/16
Champion Microelectronic Corporation
Page 4
CM8500A
3A BUS TERMINATOR
APPLICATION CIRCUIT
NOTE:
J3:referance output provided from Vtt
J4:short :Demo kit on .
open:off(into shutdown mode)
J6:reference output provided from shunt regulator
J5:pin1 ,pin2 short:Vtt = 1/2Vcc
1
2
C13
104
5
Vref -OUT
J3
TP1
BNC
When external voltage applied ,pin1,2 should be open
R8
100
and pin2:connect to external voltage (+)
4
1
pin3:connect to external voltage (-)
3
Vtt=1/2 external voltage
2
D6
100uf /6.3V
100uf /6.3V 820uf /6.3V
L1
3.3uH
R6,R7(option circuit)forVttVOLTAGEADJUST
SK12
Vtt=(Vcc*R6)/R6+R7
VTT
J1
1
2
C12
C11
D5
SK12
C7
C3
104
C2
104
C15
10uf /6.3V
VCC
U1 CM8500A
1
VDD
2
2
1
C14
100uf /6.3V
3
C4
104
R5
100k
4
5
6
J4ON/OFF 2
7
2
R6
R7
C6 8
10k
10k
102
1
1
VCC1
VCC2
VDD1
VDD2
VL1
VL2
PGND1 PGND2
AGND1 AGND4
SD
2/VCC
FB
VCCQ
G-sense AGND3
VCC
R1
5R1
J2
DC-INPUT
VDD
16
1
2
VDD
15
C16
14
C5
13
104
C1
104
C10
10uf /6.3V
470uf /6.3V
C9
100uf /6.3V
12
11
10
J5
2
9
3
1
IN/EXT
R3 200k
1
2
1
2
R4
1k
C8
102
Figure 1 . CM8500A Typical Application
(Schematic of CM8500A TEVAL)
2008/01/16
Champion Microelectronic Corporation
Page 5
CM8500A
3A BUS TERMINATOR
Figure 2. Termination Solution for PC Main Memory (Mother Boards)
Figure 3. Termination Solution for Graphic Memory (AGP Graphics)
2008/01/16
Champion Microelectronic Corporation
Page 6
CM8500A
3A BUS TERMINATOR
CM8500ATEVAL PART LIST
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Q’ty
Description
Resistors
0805, 5Ω, 1/8W
1
0805, 100Ω, 1/8W
1
0805, 470Ω, 1/8W
1
0805, 1KΩ, 1/8W
1
0805, 100KΩ, 1/8W
2
Designator
Manufacturer
R1
R8
R9 (option)
R4
R3, R5
Capacitors
1
0805, 1nF/ 16V (102)
6
0805, 0.1µF/ 16V (104)
1
0805, 1µF/ 16V (105)
CE 10φ, 820uF/ 6.3V
1
2
B Size, Tant 10uF/ 6.3V
4
D Size, Tant 100uF/ 6.3V
Magnetics
1
3.3uH 5A Inductor
IC’s
1
CM8500AIT
1
CM431L
Connectors
1
2-pin, 2.54mm
4
2-pin Jumper, 2.54mm
1
3-pin Jumper, 2.54mm
PCBs
1
CM8500ATEVAL PCB
C6, C8
C1, C2, C3, C4, C5
C13
C7
C10, C15
C9, C11, C12, C14
Sanyo OSCON
L1
Bipolar Electronic Corp.
U1
U2 (option)
Champion Microelectronic Corp.
Champion Microelectronic Corp.
J2
J1, J3, J4, J6 (option)
J5
Champion Microelectronic Corp.
Vendor Information
Bipolar Electronic Corp.
Sanyo
2008/01/16
Phn: +886-3-360 8892
Champion Microelectronic Corporation
Page 7
CM8500A
3A BUS TERMINATOR
CM8500ATEVAL PCB LAYOUT
Figure 4. CM8500AEVAL PCB Layout
SSTL-2 SPECIFICATIONS
SYMBOL
PARAMETER
MIN
TYP
MAX
UNITS
VDD
Device Supply Voltage
VDDQ
N/A
V
VDDQ
Output Supply Voltage
2.3
2.5
2.7
V
VREF
Input Reference Voltage
1.15
1.25
1.35
V
VTT
Termination Voltage
VREF - 0.04
VREF
VREF + 0.04
V
INPUT DC LOGIC LEVELS
VIH (DC)
DC Input Logic High
VREF + 0.18
VDDQ + 0.3
V
VIL (DC)
DC Input Logic Low
- 0.3
VREF - 0.18
V
INPUT AC LOGIC LEVELS
VIH (AC)
AC Input Logic High
VIL (AC)
AC Input Logic Low
V
VREF + 0.35
VREF - 0.35
V
OUTPUT DC CURRENT DRIVE
IOH (DC)
Output Minimum Source DC Current
IOL (DC)
Output Minimum Sink DC Current
Notes:
- 15.2
mA
15.2
mA
VREF and VTT must track variations in VDDQ
Peak-to-peak AC noise on VREF may not exceed ±2% VREF (DC)
VTT of transmitting device must track VREF of receiving device
Table 1. Key Specifications for SSTL_2
2008/01/16
Champion Microelectronic Corporation
Page 8
CM8500A
3A BUS TERMINATOR
SSTL_2 TERMINATED OUTPUT
Single Terminated Output
Double Terminated Output
Figure 5. SSTL_2 Terminated
Output
Note.
The SSTL_2 specification requires adequate output current drive so that parallel termination schemes can be used. The use
of parallel termination is important for high-speed signaling, since it allows proper termination of the bus transmission lines,
which reduces signal reflections. The result will be improved settling, lower EMI emissions, and higher possible clock rates. A
minimumtermination resistance of 23Ω to VTT can be used and still comply with the minimum output voltages and output
currents of
theSSTL_2 specification.
Two choices for implementing the parallel termination are shown in Figure 5.
Double Terminated Output
The bus is terminated at both ends with a 50Ω resistor, for a combined parallel resistance of 25Ω.
Single Terminated Output
The bus is terminated at the far end from the controller with a single 25Ω resistor.
It is strongly recommended that the single resistor termination scheme be used for best performance. The benefits of this
approach include reduced cost, simpler signal routing, reduced reflections, and better signal bandwidth and settling.
2008/01/16
Champion Microelectronic Corporation
Page 9
CM8500A
3A BUS TERMINATOR
CM8500AEVAL TESTING DIAGRAM
Figure 6. CM8500AEVAL Typical Testing Diagram
TYPICAL CHARACTERISTICS
CM8500 Temperature vs. VTT (VCC,VCCQ&VDD=3.3V)
1.350
VTT(V)
1.300
1A
2A
1.250
3A
1.200
1.150
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
85
T(℃ )
Temperature vs. VTT VCC, VCCQ & VDD=3.3V
2008/01/16
Champion Microelectronic Corporation
Page 10
CM8500A
3A BUS TERMINATOR
CM8500 Temperature vs. VTT (VCC,VCCQ&VDD=2.5V)
VTT(V)
1.350
1.300
1A
1.250
3A
2A
1.200
1.150
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
85
T(℃ )
Temperature vs. VTT VCC, VCCQ & VDD=2.5V
2V INPUT
2008/01/16
LOAD: 0A - 3A
2.5V INPUT
LOAD: 0A - 3A
3.3V INPUT
LOAD: 0A - 3A
2V INPUT
2.5V INPUT
3.3V INPUT
Champion Microelectronic Corporation
LOAD: 3A - 0A
LOAD: 3A - 0A
LOAD: 3A - 0A
Page 11
CM8500A
3A BUS TERMINATOR
PACKAGE DIMENSION
16-PIN PTSSOP (PT16)
16-PIN PSOP (PS16)
θ
θ
2008/01/16
Champion Microelectronic Corporation
Page 12
CM8500A
3A BUS TERMINATOR
IMPORTANT NOTICE
Champion Microelectronic Corporation (CMC) reserves the right to make changes to its products or to discontinue
any integrated circuit product or service without notice, and advises its customers to obtain the latest version of
relevant information to verify, before placing orders, that the information being relied on is current.
A few applications using integrated circuit products may involve potential risks of death, personal injury, or severe
property
or
environmental
damage.
CMC
integrated
circuit
products
are
not
designed,
intended,
authorized, or warranted to be suitable for use in life-support applications, devices or systems or other critical
applications.
Use of CMC products in such applications is understood to be fully at the risk of the customer.
In order to minimize risks associated
provide
adequate
design
and
with
the
customer’s
applications,
the
customer
operating safeguards.
HsinChu Headquarter
Sales & Marketing
5F, No. 11, Park Avenue II,
Science-Based Industrial Park,
HsinChu City, Taiwan 300
7F-6, No. 32, Sec. 1, Chenggong Rd.,
Nangang District , Taipei City 115 Taiwan
T E L : +886-3-567 9979
F A X : +886-3-567 9909
http://www.champion-micro.com
T E L : +886-2-2788 0558
F A X : +886-2-2788 2985
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Page 13
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