MAX8655ETN+T Maxim Integrated Products, MAX8655ETN+T Datasheet - Page 8

• Manufacturer Part Number: MAX8655ETN+T
• Description: IC STEP-DN REG 25A 56-TQFN-EP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX8655ETN+T

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.7 ~ 5.5 V
• Current - Output: 25A
• Frequency - Switching: 200kHz ~ 1MHz
• Voltage - Input: 4.5 ~ 25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 56-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Highly Integrated, 25A, Wide-Input,
Internal MOSFET, Step-Down Regulator
8
29, 30, 42, 49
1–5, 51–56
23, 28, 39,
6, 16–21
_______________________________________________________________________________________
7–15
PIN
22
48
24
25
26
27
31
32
33
34
35
36
37
38
VLGND
NAME
PGND
COMP
REFIN
ILIM1
PVIN
GND
N.C.
CS+
OVP
AVL
CS-
EN
LX
VL
FB
SS
IN
Power-Input Supply. PVIN connects to the drain of the internal high-side MOSFET. Connect input-
decoupling capacitors as close as possible between PVIN and PGND.
External Inductor Connection. Connect to the external power inductor. Leave pin 6 unconnected for
best routing.
Power Ground Connection from Source of Internal Low-Side MOSFET. Connect input-decoupling
capacitors as close as possible between PVIN and PGND.
Return for Low-Side MOSFET Gate-Driver Current
Analog Ground. Connect all pins to the analog ground plane, and connect the analog and power
ground planes together at the negative terminal of the output capacitor. Low-current signals return to
GND. Pin 28 must be connected externally to GND-EP, the analog ground plane.
Internal 6.5V Linear-Regulator Output. Connect a 2.2µF to 10µF ceramic capacitor from VL to VLGND.
For V
to the AVL internal linear regulator.
Input Supply Voltage. IN is the input to the VL linear regulator. Connect VL to IN for V
Decouple to PGND with a 0.22µF ceramic capacitor.
Enable. Apply logic-high to EN to enable the output, or logic-low to place the regulator in low-power
shutdown mode. Connect EN to IN for always-on operation.
Internal 5V Linear-Regulator Output. AVL powers the MAX8655’s internal circuits. Connect a 1µF
ceramic capacitor from AVL to GND.
No Connection. Not internally connected.
Positive Differential Current-Sense Input
Negative Differential Current-Sense Input
Analog Programmable Current-Limit Input for Inductor Current. Connect a resistor from ILIM1 to GND
to set the overcurrent threshold. ILIM1 sources 10µA through the resistor, and the voltage at ILIM1 is
attenuated 7.5:1 to set the final current limit. For example, a 60kΩ resistor results in 600mV at ILIM1.
This results in a current-limit threshold (V
60kΩ. Connect ILIM1 to AVL to set the default threshold of 80mV.
Output-Voltage Sensing for Overvoltage Protection. Connect OVP to the center of a resistor-divider
connected between the output of the regulator and GND to set the FB independent output
overvoltage trip point. Connect OVP to FB if this independence is not desired. The OVP threshold is
1.15 times the nominal feedback regulation voltage.
Feedback Input. Connect FB to the center of a resistor voltage-divider connected between the output
and GND to set the output voltage. FB regulates to 0.7V or V
Loop Compensation. Connect COMP to an external RC network to compensate the loop. COMP is
internally pulled to GND through 20Ω during shutdown.
Soft-Start. Connect a 0.01µF to 1µF ceramic capacitor from SS to GND. This capacitor sets the soft-
start period during startup. See the Startup and Soft-Start section for more details. SS is internally
pulled to GND through 20Ω during shutdown.
External Reference Input. Connect REFIN to AVL to use the internal 0.7V reference for the feedback
threshold.
IN
< 7V, connect VL directly to IN. VL supplies power for the internal gate drivers. VL is the input
CS+
- V
FUNCTION
CS-
) of 80mV. The ILIM1 resistor range is 24kΩ to
REFIN
.
Pin Description
IN
< 7V.