IR3475MTR1PBF International Rectifier, IR3475MTR1PBF Datasheet - Page 13

• Manufacturer Part Number: IR3475MTR1PBF
• Description: IC BUCK SYNC ADJ 10A PQFN
• Manufacturer: International Rectifier
• Series: SupIRBuck™r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of IR3475MTR1PBF

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.5 V ~ 12 V
• Current - Output: 10A
• Frequency - Switching: Up to 750kHz
• Voltage - Input: 3 V ~ 27 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: *
• Package / Case: *
• Primary Input Voltage: 27V
• No. Of Outputs: 1
• Output Voltage: 12V
• Output Current: 10A
• No. Of Pins: 17
• Operating Temperature Range: -40°C To +125°C
• Peak Reflow Compatible (260 C): Yes
• Rohs Compliant: Yes
• Leaded Process Compatible: Yes
• Part Status: Preferred
• Package: PQFN / 4 x 5
• Circuit: Single Output
• Iout (a): 10
• Switch Freq (khz): 0 - 750
• Input Range (v): 3.0 - 27
• Output Range (v): 0.5 - 12
• Ocp Otp Uvlo Pre-bias Soft Start And: Constant On-Time + PGOOD + EN + Temp Comp OCP
• Digital Home Media: Yes
• Mobile Computing: Yes
• Industrial 24v Input: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

UNDER/OVER VOLTAGE MONITOR
The IR3475 monitors the voltage at the FB node through a
350ns filter. If the FB voltage is below the under voltage
threshold, UV# is set to LOW holding PGOOD to be LOW. If
the FB voltage is above the over voltage threshold, OV# is
set to LOW, the shutdown signal (SD) is set to HIGH,
MOSFET gates are turned off, and PGOOD signal is pulled
low. Toggling VCC or EN will allow the next start up. Figure
24 and 25 show PGOOD status change when UV/OV is
detected. The over voltage and under voltage thresholds
can be found in the Electrical Specification section.
Figure 24: Under/Over Voltage Monitor
13
Figure 25: Over Voltage Protection
February 16, 2011 | ADVANCED DATASHEET | V1.8 | PD97602
* typical filter delay
* typical filter delay
10A Highly Integrated SupIRBuck
OVER CURRENT MONITOR
The over current circuitry monitors the output current
during each switching cycle. The voltage across the lower
MOSFET, VPHASE, is monitored for over current and zero
crossing. The minimum lower gate interval allows time to
sample VPHASE.
The over current trip point is programmed with a resistor
from the ISET pin to PHASE pin, as shown in equation 4.
When over current is detected, the MOSFET gates are tri‐
state and SS voltage is pulled to 0V. This initiates a new
soft start cycle. If there is a total of four OC events, the
IR3475 will disable switching. Toggling VCC or EN will allow
the next start up.
UNDER VOLTAGE LOCK‐OUT
The IR3475 has VCC and EN under voltage lock‐out (UVLO)
protection. When either VCC or EN is below their UVLO
threshold, IR3475 is disabled. IR3475 will restart when
both VCC and EN are above their UVLO thresholds.
OVER TEMPERATURE PROTECTION
When the IR3475 exceeds its over temperature threshold,
the MOSFET gates are tri‐state and PGOOD is pulled low.
Switching resumes once temperature drops below the over
temperature hysteresis level.
Figure 26: Over Current Protection
R
SET

R
DSON
19
TM


I
A
OC
IR3475
(4)