MAX8794 Maxim Integrated Products, MAX8794 Datasheet - Page 8

• Manufacturer Part Number: MAX8794
• Description: Low-Voltage DDR Linear Regulator
• Manufacturer: Maxim Integrated Products

Low-Voltage DDR Linear Regulator
The MAX8794 is a low-voltage, low-dropout DDR termi-
nation linear regulator with an external bias supply
input and a buffered reference output (see Figures 1
and 2). V
commonly available in laptop and desktop computers.
The 3.3V bias supply drives the gate of the internal
pass transistor, while a lower voltage input at the drain
of the transistor (IN) is regulated to provide V
using separate bias and power inputs, the MAX8794
can drive an n-channel high-side MOSFET and use a
lower input voltage to provide better efficiency.
The MAX8794 regulates its output voltage to the volt-
age at REFIN. When used in DDR applications as a ter-
mination supply, the MAX8794 delivers 1.25V or 0.9V at
3A peak (typ) from an input voltage of 1.1V to 3.6V. The
MAX8794 sinks up to 3A peak (typ) as required in a ter-
mination supply. The MAX8794 provides shoot-through
protection, ensuring that the source and sink MOSFETs
do not conduct at the same time, yet produces a fast
source-to-sink load transient.
Figure 2. Functional Diagram
8
V
DDQ
_______________________________________________________________________________________
OFF
3.3V BIAS
SUPPLY
POWER-
GOOD
V
ON
TTR
CC
is powered by a 2.7V to 3.6V supply that is
Detailed Description
REFIN
REFOUT
PGOOD
V
SHDN
AGND
CC
Gm
UVLO
DELAY
LOGIC
OUT
THERMAL
. By
SHDN
REFIN
+150mV
REFIN
-150mV
Figure 1. Standard Application Circuit
1.1V TO 3.6V
V
3.3V BIAS
DDQ
OFF
POWER-GOOD
SUPPLY
EN
V
IN
=
10kΩ
SOFT-
START
R1
100kΩ
ON
10kΩ
R2
R3
1000pF
C
1.0µF
10µF
REFIN
C
EN
IN2
C1
MAX8794
IN
V
PGOOD
SHDN
REFIN
CC
8Ω
MAX8794
12kΩ
PGND
OUTS
OUT
IN
REFOUT
PGND
AGND
OUTS
OUT
100µF
C
OUT1
V
INPUT
1.1V TO 3.6V
OUT
V
REFOUT
C
0.33µF
= V
REFOUT
TT
= V
= V
TTR
DDQ
V
TT
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