PTHxx050Y —Series
6-A Non-Isolated DDR/QDR Memory
Bus Termination Modules
SLTS221 – MARCH 2004
Features
• VTT Bus Termination Output
• Efficiencies up to 88 %
• 50 W/in³ Power Density
• Output Over-Current Protection
(Non-Latching, Auto-Reset)
• Safety Agency Approvals (Pending):
UL/cUL60950, EN60950, VDE
• Point-of-Load Alliance (POLA)
Compatible
(Output Tracks the System VREF
• 6 A Output Current (8 A Peak)
• 3.3-V, 5-V or 12-V Input Voltage
• DDR & QDR Compatible
)
• On/Off Inhibit (for VTT Standby)
• Under-Voltage Lockout
• Operating Temp: –40 to +85 °C
NOMINAL
SIZE
=0.87
in
x
0.5
in
(22,1 mm x 12,57 mm)
Description
Pin Configuration
The PTHxx050Y are a series of ready-
to-use switching regulator modules from
Texas Instruments designed specifically for
bus termination in DDR and QDR memory
applications. Operating from either a 3.3-V,
5-V or 12-V input, the modules generate
a VTT output that will source or sink up
to 6 A of current (8 A transient) to accu-
rately track their VREF input. VTT is the
required bus termination supply voltage,
and VREF is the reference voltage for the
memory and chipset bus receiver com-
parators. VREF is usually set to half the
VDDQ power supply voltage.
output to provide state-of-the-art step-
down switching conversion. The products
are small in size (0.87 in × 0.5 in), and are
an ideal choice where space, performance,
and high efficiency are desired, along with
the convenience of a ready-to-use module.
Operating features include an on/off
inhibit and output over-current protection
(source mode only). The on/off inhibit
feature allows the VTT bus to be turned
off to save power in a standby mode of
operation.
Pin Function
1
2
3
4
5
6
GND
VREF
VIN
Inhibit *
No Connect
VTT
*
Denotes negative logic:
Open
= VTT Output On
Ground = VTT Output Off
Package options include both through-
hole and surface mount configurations.
Both the PTHxx050Y series employs
an actively switched synchronous rectifier
Standard Application
VIN
VDDQ
VREF
1 k
1 %
VTT
1
2
3
4
6
5
PTHxx050Y
(Top View)
1 k
1 %
Con
hf-Ceramic
Co1
Low-ESR
(Required)
Co2
Ceramic
(Optional)
CIN
(Required)
SSTL-2
Data/
Address
Bus
Q1
BSS138
(Optional)
Standby
GND
C
= Required electrolytic capacitor; 220 µF (3.3-/5-V input), 560 µF (12-V input).
in
Co1 = Required low-ESR electrolyitic capacitor; 470 µF (3.3-/5-V input), 940 µF (12-V input).
Co2 = Ceramic capacitance for optimum response to a 3-A ( 1.5-A) load transient.; 200 µF (3.3-/5-V input), 400 µF (12-V input).
Con = Distributed hf-ceramic decoupling capacitors for VTT bus; as recommended for DDR memory appications.
For technical support and further information, visit http://power.ti.com