MIC5163YMM Micrel Inc, MIC5163YMM Datasheet - Page 11

• Manufacturer Part Number: MIC5163YMM
• Description: IC REG CTLR DUAL MEM TERM 10MSOP
• Manufacturer: Micrel Inc

Specifications of MIC5163YMM

• Applications: Controller, DDR3, GDDR3/4/5
• Voltage - Input: 0.75 ~ 6 V
• Number Of Outputs: 1
• Voltage - Output: Programmable
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3482-5

V
A separate voltage source can be used to externally set
the reference point, bypassing the divider network. Also,
external resistors can be added from V
V
V
V
provides the drive voltage to enhance the external N-
Channel
recommended for bypassing the V
V
without exceeding 6V. For example, on an DDR3
compliant terminator, V
0.75V. If the N-Channel MOSFET selected requires a
gate source voltage of 2.5V, V
of 3.25V
Feedback and Compensation
The feedback provides the path for the error amplifier to
regulate V
between the feedback and V
amplifier to be correctly externally compensated. For
most applications, a 510Ω resistor is recommended. The
COMP pin on the MIC5163 is the output of the internal
error amplifier. By placing a capacitor and resistor
between the COMP pin and the feedback pin, this
coupled with the feedback resistor, places an external
pole and zero on the error amplifier. With a 510Ω
feedback resistor, a minimum 220pF capacitor is
recommended for a 3.5A peak termination circuit. An
increase in the load will require additional N-Channel
MOSFETs and/or increase in output capacitance may
require feedback and/or compensation capacitor values
to be changed to maintain stability. Feedback resistor
values should not exceed 10kΩ and compensation
capacitors should not be less than 40pF.
Enable
The MIC5163 features an active high enable input. In the
off mode state, leakage currents are reduced to
microamperes.
Micrel, Inc.
April 2009
REF
REF
CC
CC
CC
-to-V
voltage should be a gate-source voltage above V
supplies the internal circuitry of the MIC5163 and
can also be manipulated for different applications.
Figure 5. V
DDQ
MOSFETs.
TT
to shift the reference point up or down.
. An external resistor must be placed
The
DDQ
120pF
VREF
Divided Down to Provide V
enable
DDQ
A
equals 1.5V and V
small
GND
VDDQ
TT
CC
. This allows the error
input
should be a minimum
CC
1μF
pin. The minimum
has
REF
-to-ground or
capacitor
thresholds
REF
TT
equals
TT
is
11
compatible with TTL/CMOS for simple logic interfacing.
The enable pin can be tied directly to V
functionality. Do not float the enable pin. Floating this pin
causes the enable to be in an indeterminate state.
Input Capacitance
Although the MIC5163 does not require an input
capacitor for stability, using one greatly improves device
performance. Due to the high-speed nature of the
MIC5163, low ESR capacitors such as Oscon and
ceramics are recommended for bypassing the input. The
recommended value of capacitance will depend greatly
on the proximity to the bulk capacitance. Although a
10μF ceramic capacitor will suffice for most applications,
input capacitance may need to be increased in cases
where the termination circuit is greater than 1-inch away
from the bulk capacitance.
Output Capacitance
Large, low ESR capacitors are recommended for the
output (V
capacitors are not required for stability, they are
recommended to reduce the effects of high-speed
current transients on V
the transient condition will be the effect of the peak
current multiplied by the output capacitor’s ESR. For that
reason, Oscon type capacitors and ceramic are excellent
choices for this application. Oscon capacitors have
extremely low ESR and a large capacitance-to-size ratio.
Ceramic capacitors are also well suited to termination
due to their low ESR. These capacitors should have a
dielectric rating of X5R or X7R. Y5V and Z5U type
capacitors are not recommended, due to their poor
performance at high frequencies and over temperature.
The minimum recommended capacitance for a 3.5A
peak circuit is 100μF. Output capacitance can be
increased to achieve greater transient performance.
MOSFET Selection
The MIC5163 utilizes external N-Channel MOSFETs to
sink and source current. MOSFET selection will settle to
two main categories: size and gate threshold (V
MOSFET Power Requirements
One of the most important factors is to determine the
amount of power the MOSFET is going to be required to
dissipate. Power dissipation in a DDR3 circuit will be
identical for both the high side and low side MOSFETs.
Since the supply voltage is divided by half to supply V
both MOSFETs have the same voltage dropped across
them. They are also required to be able to sink and
source the same amount of current (for either all 0s or all
1s). This equates to each side being able to dissipate
the
calculation for the high-side MOSFET is as follows:
same
TT
) of the MIC5163. Although low ESR
amount
TT
of
. The change in voltage during
power.
Power
M9999-042209-A
DDQ
dissipation
MIC5163
or V
GS
).
CC
for
TT
,