BD3538F_15 Datasheet, PDF (1/20 Pages) Rohm – Termination Regulators for DDR-SDRAMs

Datasheet
Termination Regulators for DDR-SDRAMs
BD3538F BD3538HFN
General Description
BD3538F/HFN is a termination regulator that complies
with JEDEC requirements for DDR-SDRAM. This
linear power supply uses a built-in N-channel MOSFET
and high-speed OP-AMPS specially designed to
provide excellent transient response. It has a
sink/source current capability of up to 1A and has a
power supply bias requirements of 3.3V to 5.0V for
driving the N-channel MOSFET. By employing an
independent reference voltage input (VDDQ) and a
feedback pin (VTTS), this termination regulator
provides excellent output voltage accuracy and load
regulation as required by JEDEC standards.
Additionally, BD3538 has a reference power supply
output (VREF) for DDR-SDRAM or a memory
controller. Unlike the VTT output that goes to “Hi-Z”
state, the VREF output is kept unchanged when EN
input is changed to “Low”, making this IC suitable for
DDR-SDRAM under “Self Refresh” state.
Features
 Incorporates a push-pull power supply for
termination (VTT)
 Incorporates a reference voltage circuit (VREF)
 Incorporates an enabler
 Incorporates an undervoltage lockout (UVLO)
 Incorporates a thermal shutdown protector (TSD)
 Compatible with Dual Channel (DDR-II)
Key Specifications
 Termination Input Voltage Range: 1.0V to 5.5V
 VCC Input Voltage Range:
2.7V to 5.5V
 VDDQ Reference Voltage Range: 1.0V to 2.75V
 Output Voltage:
1/2 x VVDDQ V(Typ)
 Output Current:
1.0A (Max)
 High side FET O-Resistance:
0.4Ω(Typ)
 Low side FET ON-Resistance:
0.4Ω(Typ)
 Standby Current:
0.5mA (Typ)
 Operating Temperature Range: -40°C to +105°C
Packages
W(Typ) x D(Typ) x H(Max)
SOP8
5.00mm x 6.20mm x 1.71mm
Applications
Power supply for DDR I / II - SDRAM
HSON8
2.90mm x 3.00mm x 0.60mm
Typical Application Circuit, Block Diagram
VCC
VDDQ
VTT_IN
VCC
6
VCC
VDDQ
5
VCC
VCC
VTT_IN
7
Reference
Block
Thermal ^TSD
Protection
Enable
EN
EN
2
UVLO
SOFT
UVLO
TSD
EN
UVLO
TSD
VCC ^EN
UVLO
TSD
EN
UVLO
VTT
8
3
VTTS
4
VREF
VTT
½x
VDDQ
1
GND
○Product structure：Silicon monolithic integrated circuit
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TSZ22111・14・001
○This product has no designed protection against radioactive rays
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TSZ02201-0J2J0A900980-1-2
02.Nov.2015 Rev.001