CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 1
GENERAL DESCRIPTION
FEATURES
! Patent Filed #6,452,366
! 16 pin PTSSOP and 16 pin PSOP power packages
! Source and sink up to 2A, no heat sink required
! Integrated Power MOSFETs
! Output voltage can be programmed by external resistors
! Separate voltages for VCCQ and PVDD
! V OUT of ±3% or less at 2A
! Minimum external components
! Shutdown for standby or suspend mode operation
! Thermal shutdown protection
! Soft start
The CM8502 is a low cost switching regulator designed to
provide a desired output voltage or termination voltage for
various applications by converting voltage supplies ranging
from 2.0V to 4.0V. The CM8502 can be implemented to
produce regulated output voltages in two different modes. In
the default mode, when the VIN/2 pin is open, the output
voltage is 50% of the VCCQ. The CM8502 can also be used
to produce various user-defined voltages by forcing a voltage
on the VIN/2 pin. In this case, the output voltage follows the
VIN/2 pin input voltage. The switching regulator is capable of
sourcing or sinking up to 2A of current while regulating an
output V TT voltage to within 3% or less.
The CM8502 provides low profile 16-pin PSOP and PTSSOP
packages that are pin-to-pin compatible to the previous
CM8500.
24 Hours Technical Suppor t---WebSIM
Champion provides customers an online circuit simulation tool
called WebSIM. You could simply logon our website at
www.champion-micro.com for details.
APPLICATIONS
! Mother Board
! PCI/AGP Graphics
! Game/ Play Station
! Set Top Box
! IPC
! SCSI-III Bus terminator
! Buck Converter
PIN CONFIG UR ATION
PSOP-16 (PS16)/PTSSOP-16 (PT16)
Top View
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VCCA
NC
NC
NC
AGND
SD
VIN/2
AGSEN
NC
PVDD
VL
PGND
NC
VFB
VCCQ
NC
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 2
PIN DESCRIPTION Operating Rating
Pin No. Symbol Description Min. Typ. Max. Unit
1 VCCA Voltage supply for internal circuits 2 2.5 4 V
2,3,4,9,12,16 NC No Connection
5 AGND Ground for internal reference voltage divider
6 SD Shutdown active high. CMOS input level 0.75 x
VCCA
VCCA
+ 0.3V
V
7 VIN/2 Input for external reference voltage VCCQ/2 V
8 AGSEN Ground for remote sensing
10 VCCQ Voltage reference for external voltage divider 2.5 V
11 VFB Feedback node for the VTT VCCQ/2 V
13 PGND Ground for output power transistors
14 VL Output voltage/inductor connection (IDD1+IDD2,
Output RMS current)
2 A
15 PVDD Voltage supply for output power transistors 2 2.5 4 V
ORDERING INFORMATION
Part Number Temperature Range Package
CM8502IT -40℃ to 85℃ 16-Pin PTSSOP (PT16)
CM8502IS -40℃ to 85℃ 16-Pin PSOP (PS16)
BLOCK DIAGR AM
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 3
APPLIC ATION CIRCUI TS
R6
5R1 2
1
2A DDR BUS TERMINATOR DEMO BOARD
CIRCUIT
C3
470
U2
CM-431
1 3
2
J3
VREF-OUT
1
2C9
102
C5 104
C6
220uf/6.3V
J2
VTT
1
2
J1
PWR/IN
1
2
L1
3.3uH
JP3---->USEING INTERNAL REFERENCE
SOURCE(PIN 1, 2 SHORT)
R4
1k
2
1
JP3
CON3
1
2
3
C4 105
VCC
R3
100k
2 1
VCC
D1
SK12
JP4 on/off sw
C7
104
D2
SK12
R2
1k
2
1
JP2
JUMPER
U1 CM8502
2
1
3
413
14
15
16
5
6
7
8 9
10
11
12
NC
VCCA
NC
NC PGND
VL
PVDD
NC
AGND
SD
VIN/2
AGSEN NC
VCCQ
VFB
NC
C8
10uf/6.3V
VDD
VDD
JP3---->USEING EXTERNAL REFERENCE
SOURCE(PIN 2,3 SHORT)
R1
100k
2
1
R5
0
2 1
JP1
JUMPER
C1 100uf/6.3V
NOTE:
TP1
BNC
1
2
3
4
5
C2 105
16-Pin Schematic
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 4
A BSOLUTE MAXIMUM RATINGS
Junction Temperature ...…………………… …………150°C Absolute maximum ratings are those values beyond which the
device could be permanently damaged. Storage Temperature ……................……. -65°C to 125°C
PVDD/VCCA/VCCQ ......................................….......-0.3V to 4.0V Lead Temperature (Soldering, 5 sec)……………….. 300°C
Voltage on Any Other Pin ………... GND – 0.3V to VCC + 0.3V Thermal Resistance (θJA )….. ………………….. .40°C/W
Output RMS Current, Source or Sink ......…………........…...2A
OPERATING CONDITIONS
Temperature Range ............................. -40°C to 85°C
PVDD Operating Range .........................2.0V to 4.0V
ELECTRICAL CHARACTERISTICS (Unless otherwise stated, these specifications apply TA=25°C;
VCCA=+3.3V and PVDD=+3.3V) maximum ratings are stress ratings only and functional device operation is not implied.
(Note 1)
CM8502
Symbol Parameter Test Conditions
Min. Typ. Max.
Unit
SWITCHING REGULATOR
VCCQ = 2.3V 1.12 1.15 1.18 V
VCCQ = 2.5V 1.22 1.25 1.28 V
IOUT = 0,
Note 2 VCCQ = 2.7V 1.32 1.35 1.38 V
VCCQ = 2.3V 1.09 1.15 1.21 V
VCCQ = 2.5V 1.19 1.25 1.31 V
VL
Output Voltage, SSTL_2 IOUT =
±2A,
Note 2
Note 3 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
VIN/2 Internal Resistor Divider IOUT = 0
Note 2 VCCQ = 2.7V 1.337 1.35 1.364 V
ZIN V
IN/2 Reference Pin Input Impedance Note 2 VCCQ = 0 50 KΩ
fsw Switching Frequency CM8502 1.2 MHz
IOUT(RMS) Maximum Output RMS Current CM8502 2.0 A
IOUT(PEAK) Maximum Output Peak Current CM8502 4.0 A
MOSFETs
RDS(ON) Drain to Source on-State Resistance PVDD=5V 250 mΩ
SUPPLY
IQ Quiescent Current
IOUT = 0,
no load Icc + Idd 10 mA
IVCCA Quiescent Current VFB = 1.4V
LC unconnected 220 µA
IPVDD VFB = 1.4V
LC unconnected 500 µA
Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions
Note 2: VCCA, PVDD = 3.3V ±10%, VIN/2=open for CM8502
Note 3: Guaranteed by design, not 100% test
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 5
FUNCTIONAL DESCRIPTI O N
The CM8502 is a switching regulator that is capable of sinking
and sourcing 2A of current without an external heat sink.
CM8502 uses a standard surface mount PTSSOP and PSOP
package with bottom metal exposed and the heat can be
piped through the bottom of the device and onto the PCB.
The CM8502 integrates power MOSFETs that are capable of
source and sink 2A of current while maintaining excellent
voltage regulation. The output voltage can be regulated within
3% or less by using the external feedback. Separate voltage
supply inputs have been added to fit applications with various
power supplies for the databus and power buses.
OUPUTS
The output voltage pins (VL) are tied to the databus, address,
or clock lines via an external inductor. Output voltage is
determined by the VCCQ or VIN/2 inputs for CM8502.
INPUTS
The input voltage pins (VCCQ & VIN/2 of CM8502) determine
the output voltages (VL). At CM8502, when the VIN/2 pin is
open, the output voltage is 50% of the VCCQ input. If a specific
voltage is forced at the VIN/2 pin, the output voltage follows the
voltage at the VIN/2 pin.
VCCQ is suggested to connect to VCCQ of memory module for
better tracking with memory VCCQ.
OTHER SUPPLY VOLTAGES
Several inputs are provided for the supply voltages: PVDD and
VCCA
The PVDD provide the power supply to the power MOSFETs.
VCCA provide the voltage supply to the logic section and
internal error amplifiers of CM8502.
FEEDBACK
The VFB pin is an input that can be used for closed loop
compensation. This input is derived from the voltage output.
AGSEN pin is a contact node of internal resistor divider for
remote sense (CM8502).
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 6
PACKAGE DIMENSIO N
16-PIN PTSSOP (PT16)
θ
θ
16-PIN PSOP (PS16)
θ
θ
CM8502
2A BUS TERMINATOR
2002/09/30 Rev. 1.0 Champion Microelectronic Corporation Page 7
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 with the customer’s applications, the customer should provide adequate design and operating
safeguards.
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