Termination Regulators. BD3533F Datasheet

BD3533F Regulators. Datasheet pdf. Equivalent

Part BD3533F
Description Termination Regulators
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Manufacture Rohm
Total Page 20 Pages
Datasheet
Download BD3533F Datasheet



BD3533F
Datasheet
1.0V to 5.5V, 1A 1ch
Termination Regulators for DDR-SDRAMs
BD3533F BD3533FVM BD3533HFN
General Description
BD3533 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
up to 1A and has a power supply bias requirement 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, BD3533 has a
reference power supply output (VREF) for DDR-SDRAM
or for memory controllers. 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.
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 VDDQ V (Typ)
Output Current:
BD3533F
3.0A(Max)
BD3533FVM/HFN
1.0A(Max)
High Side FET ON-Resistance:
0.4(Typ)
Low Side FET ON-Resistance:
0.4(Typ)
Standby Current:
0.5mA(Typ)
Operating Temperature Range: -20°C to +100°C
Packages
W(Typ) x D(Typ) x H(Max)
Features
Incorporates a Push-Pull Power Supply for
Termination (VTT)
Incorporates a Reference Voltage Circuit (VREF)
Incorporates an Enabler
Incorporates an Under Voltage Lockout (UVLO)
Incorporates a Thermal Shutdown Protector (TSD)
Compatible with Dual Channel (DDR-2)
SOP8
5.00mm x 6.20mm x 1.71mm
Applications
Power Supply for DDR 1/2/3/4 - SDRAM
Power Supply for GDDR 1/2/3/4/5 - SDRAM
Power Supply for LPDDR 1/2/3/4 - SDRAM
MSOP8
HSON8
2.90mm x 4.00mm x 0.90mm 2.90mm x 3.00mm x 0.60mm
Typical Application Circuit, Block Diagram
VCC
VDDQ
VTT_IN
VCC
6
VDDQ
5
VTT_IN
7
VCC
VCC
VCC
Reference
Block
Enable EN
2
Thermal TSD
Protection
EN
UVLO
SOFT
TSD
UVLO EN
UVLO
TSD
VCC EN
UVLO
TSD
EN
UVLO
VTT
8
3
VTTS
4
VREF
1
GND
VTT
½x
VDDQ
Product structureSilicon monolithic integrated circuit
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ2211114001
This product has no designed protection against radioactive rays
1/17
TSZ02201-0J1J0A900700-1-2
07.Mar.2014 Rev.001



BD3533F
BD3533F BD3533FVM BD3533HFN
Datasheet
Pin Configuration
TOP VIEW
GND 1
EN 2
VTTS 3
VREF 4
8 VTT
7 VTT_IN
6 VCC
5 VDDQ
Pin Descriptions
Pin No.
Pin Name
1 GND
2 EN
3 VTTS
4 VREF
5 VDDQ
6 VCC
7 VTT_IN
8 VTT
Bottom
(only BD3533HFN)
FIN
Pin Function
GND pin
Enable input pin
Detector pin for termination voltage
Reference voltage output pin
Reference voltage input pin
VCC pin
Termination input pin
Termination output pin
Substrate
(connected to GND)
Description of Blocks
1. VCC
The VCC pin is for the independent power supply input that operates the internal circuit of the IC. It is the voltage at this
pin that drives the IC’s amplifier circuits. The VCC input ranges from 3.3V to 5V and maximum current consumption is
4mA. A bypass capacitor of 1μF or so should be connected to this pin when using the IC in an application circuit.
2. VDDQ
This is the power supply input pin for an internal voltage divider network. The voltage at VDDQ is halved by two 50k
internal voltage-divider resistors and the resulting voltage serves as reference for the VTT output. Since VTT = 1/2VDDQ,
the JEDEC requirement for DDR-SDRAM can be satisfied by supplying the correct voltage to VDDQ.
Noise input should be avoided at the VDDQ pin as it is also included by the voltage-divider at the output. An RC filter
consisting of a resistor and a capacitor (220and 2.2μF, for instance,) may be used to reduce the noise input but make
sure that it will not significantly affect the voltage-divider’s output.
3. VTT_IN
VTT_IN is the power supply input pin for the VTT output. Input voltage may range from 1.0V to 5.5V, but consideration
must be given to the current limit dictated by the ON-Resistance of the IC and to the change in allowable loss due to
input/output voltage difference.
Generally, the following voltages are supplied:
DDR1
VTT_IN = 2.5V
DDR2
VTT_IN = 1.8V
DDR3
VTT_IN = 1.5V
DDR4
VTT_IN = 1.2V
Take note that a high-impedance voltage input at VTT_IN may result in oscillation or degradation in ripple rejection, so
connecting a 10µF capacitor with minimal change in capacitance to VTT_IN terminal is recommended. However, this
impedance may depend on the characteristics of the power supply input and the impedance of the PC board wiring,
which must be carefully checked before use.
4. VREF
BD3533 provides a constant voltage, VREF, which is independent from the VTT output and can serve as reference input
for memory controllers and DRAMs. The voltage level of VREF is kept constant even if the EN pin is at “Low” level,
making the use of this IC compatible with the “Self Refresh” state of DRAMs.
In order to stabilize the output voltage, connecting the correct combination of capacitor and resistor to VREF is necessary.
For this purpose, a combination of 1.0μF to 2.2μF ceramic capacitor, characterized by minimal variation in capacitance,
and a 0.5to 2.2phase compensating resistor is recommended. A 10μF ceramic or tantalum capacitor can also be
used. The maximum current capability of the VREF pin is 20mA, but for an application which consumes a small amount
of VREF current, using a capacitance of 1μF or less will do.
5. VTTS
VTTS is a sense pin for the load regulation of the VTT output voltage. In case the wire connecting VTT pin and the load is
too long, connecting VTTS pin to the part of the wire nearer to the load may improve load regulation.
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ2211115001
2/17
TSZ02201-0J1J0A900700-1-2
07.Mar.2014 Rev.001





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