MAX1544ETL+T Maxim Integrated Products, MAX1544ETL+T Datasheet - Page 22

• Manufacturer Part Number: MAX1544ETL+T
• Description: IC QUICK-PWM DUAL-PHASE 40-TQFN
• Manufacturer: Maxim Integrated Products
• Series: Quick-PWM™r

Specifications of MAX1544ETL+T

• Applications: Controller, AMD Hammer
• Voltage - Input: 2 ~ 28 V
• Number Of Outputs: 1
• Voltage - Output: 0.68 ~ 1.55 V
• Operating Temperature: -40°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Output Voltage: 0.675 V to 1.55 V
• Output Current: 40 A
• Input Voltage: 4 V to 28 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

as the surge current is less than the current limit set by
ILIM. The transition time is given by:
where f
original DAC setting, V
V
The additional two clock cycles on the falling edge time
are due to internal synchronization delays. See TIME
Frequency Accuracy in the Electrical Characteristics for
f
The practical range of R
sponding to 1.0µs to 10µs per 25mV step. Although the
DAC takes discrete steps, the output filter makes the
transitions relatively smooth. The average inductor cur-
rent required to make an output voltage transition is:
Dual-Phase, Quick-PWM Controller for
AMD Hammer CPU Core Power Supplies
Figure 4. Suspend Transition
22
SLEW
t
t
LSB
SLEW
SLEW
CLOCK
______________________________________________________________________________________
VROK
V
TIME
= 25mV is the DAC’s smallest voltage increment.
SUS
DAC
limits.
SLEW
≈
≈
f
f
SLEW
SLEW
1
1
= 500kHz
I
L










V
≅
t
V
OLD
SLEW
C
OLD
OUT
V
NEW
V
LSB
−
VROK BLANKING
LSB
−
TIME
✕
V
×
V
NEW
30kΩ / R
is the new DAC setting, and
NEW
V
LSB
is 15kΩ to 150kΩ, corre-
t
BLANK




 +

×
for V
= 24 CLKS
f
SLEW
2




TIME
OUT
for V
, V
OUT
ri
sin
OLD
OUTPUT SET BY SUS AND S0-S1
g
falling
1 LSB PER R
is the
TIME
CYCLE
The MAX1544 features selectable output OVP. Connect
OVP to V
tection. The OVP circuit is designed to protect the CPU
against a shorted high-side MOSFET by drawing high
current and blowing the battery fuse. The MAX1544
continuously monitors the output for an overvoltage
fault. During normal forced-PWM operation (SKIP =
high), the controller detects an OVP fault if the output
voltage exceeds the set DAC voltage by more than 13%
(min). During pulse-skipping operation (SKIP = REF or
GND), the controller detects an OVP fault if the output
voltage exceeds the fixed 2.0V (typ) threshold. When
the OVP circuit detects an overvoltage fault, it immedi-
ately sets the fault latch and activates the shutdown
sequence.
This action discharges the output filter capacitor and
forces the output to ground. If the condition that caused
the overvoltage (such as a shorted high-side MOSFET)
persists, the battery fuse blows. The controller remains
shut down until the fault latch is cleared by toggling
SHDN or cycling the V
To disable the overvoltage protection, connect OVP to
GND. The OVP is also disabled when the controller is in
the no-fault test mode (see the No-Fault Test Mode
section).
CC
to enable the output overvoltage-fault pro-
t
SLEW
CC
Output Overvoltage Protection
VROK BLANKING
power supply below 1V.
OUTPUT SET BY D0–D4
t
BLANK
= 24 CLKS
Fault Protection