MAX8760ETL+T Maxim Integrated Products, MAX8760ETL+T Datasheet - Page 17

• Manufacturer Part Number: MAX8760ETL+T
• Description: IC CNTRLR QUICK PWM 40-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX8760ETL+T

• Applications: Controller, 6-bit VID AMD Mobile Turion™
• Voltage - Input: 4 ~ 28 V
• Number Of Outputs: 2
• Voltage - Output: 0.38 ~ 1.55 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Output Voltage: 0.375 V to 1.55 V
• Output Current: 4000 mA
• Mounting Style: SMD/SMT
• Switching Frequency: 550 KHz
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 40 C
• Synchronous Pin: No
• Topology: Buck
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

For the MAX8760, the slew-rate controller ramps up the
output voltage in 12.5mV increments to the proper oper-
ating voltage (see Tables 3 and 4) set by either D0–D5
(SUS = GND) or S0, S1 (SUS = REF or high). The ramp
rate is set with the R
Transition Timing section).
The ramp rate is 1/4 the rate set by the R
(see the Output Voltage Transition Timing section). The
controller pulls VROK low until at least 3ms after the
MAX8760 reaches the target DAC code.
When SHDN goes low, the MAX8760 enters low-power
shutdown mode. VROK is pulled low immediately, and
the output voltage ramps down to 0V in LSB increments
at 4 times the clock rate set by R
where f
setting when the controller begins the shutdown
sequence, and V
voltage increment. Slowly discharging the output capac-
itors by slewing the output over a long period of time
(4/f
Table 1. Component Selection for Standard Multiphase Applications
Input Voltage Range
VID Output Voltage
(D5–D0)
Suspend Voltage
(SUS, S0, S1)
Maximum Load Current
Number of Phases (η
Inductor (per Phase)
Switching Frequency
High-Side MOSFET (N
Low-Side MOSFET (N
Total Input Capacitance (C
Total Output Capacitance (C
Current-Sense Resistor (R
SLEW
SLEW
) keeps the average negative inductor current
= 500kHz
DESIGNATION
Dual-Phase, Quick-PWM Controller for AMD
Mobile Turion 64 CPU Core Power Supplies
t
SHDN
LSB
______________________________________________________________________________________
TOTAL
L
TIME
H
, per phase)
, per phase)
= 12.5mV is the DAC’s smallest
≤
SENSE
✕
IN
)
f
resistor (see the Output Voltage
SLEW
30kΩ/R
OUT
)
4
, per Phase)
)
⎛
⎜
⎝
V
V
TIME
TIME
DAC
LSB
:
, V
⎞
⎟
⎠
DAC
Shutdown
TIME
is the DAC
resistor
low (damped response), thereby eliminating the nega-
tive output voltage excursion that occurs when the con-
troller discharges the output quickly by permanently
turning on the low-side MOSFET (underdamped
response). This eliminates the need for the Schottky
diode normally connected between the output and
ground to clamp the negative output voltage excursion.
When the DAC reaches the 0V setting, DL_ goes high,
DH_ goes low, the reference turns off, and the supply
current drops to about 1µA. When a fault condition—out-
put undervoltage lockout, output overvoltage lockout, or
thermal shutdown—activates the shutdown sequence,
the controller sets the fault latch to prevent the controller
from restarting. To clear the fault latch and reactivate the
controller, toggle SHDN or cycle V
When SHDN goes high, the reference powers up. Once
the reference voltage exceeds its UVLO threshold, the
controller evaluates the DAC target and starts switching.
The slew-rate controller ramps up from 0V in LSB
increments to the currently selected output-voltage set-
ting at 1/4 the slew rate set by the R
Power-Up Sequence section). There is no traditional soft-
start (variable current-limit) circuitry, so full output current
is available immediately.
MAX8760 AMD MOBILE COMPONENTS
0.56µH Panasonic ETQP4LR56WFC
Taiyo Yuden TMK432BJ106KM or
Panasonic ERJM1WTJ1M0U
TDK C4532X5R1E106M
Siliconix (1) Si7886DP
Siliconix (2) Si7356DP
Sanyo 2R5TPE330M9
300kHz (TON = REF)
Circuit of Figure 1
(D5–D0 = 001010)
(4) 330µF, 2.5V
(SUS = GND)
(4) 10µF, 25V
Two phases
7V to 24V
Not used
1mΩ
1.3V
30A
CC
TIME
power below 1V.
resistor (see the
17