SC418ULTRT Semtech, SC418ULTRT Datasheet - Page 11

• Manufacturer Part Number: SC418ULTRT
• Description: IC BUCK SYNC ADJ 20MLPQ
• Manufacturer: Semtech
• Series: EcoSpeed™, SmartDrive™r
• Type: Step-Down (Buck)r

Specifications of SC418ULTRT

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.5 ~ 5.5 V
• Frequency - Switching: 200kHz ~ 1MHz
• Voltage - Input: 3 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-MLPQ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Other names: SC418ULTRTTR

Pin Descriptions
Pin #
PAD
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
Pin Name
PGOOD
VDDA
PGND
AGND
AGND
VOUT
VLDO
VDDP
TON
ILIM
BST
PSV
ENL
FBL
VIN
DH
NC
DL
EN
FB
LX
Pin Function
Feedback input for switching regulator — connect to an external resistor divider from output — used to
program the output voltage.
Feedback input for the LDO — connect to an external resistor divider from VLDO to AGND — used to pro-
gram the LDO output.
Supply input for internal analog circuits — connect to external 3.3V or 5V supply, or configure the LDO for
3.3V or 5V and connect to VLDO — also the sense input for VDDA UVLO.
Switcher output voltage sense pin — also the input to the internal switch-over MOSFET between VOUT and
VLDO. The voltage at this pin must be less than or equal to the voltage at the VDDA pin.
No Connection
Input supply voltage — connect to the same supply used for the high-side MOSFET. Connect a 100nF ca-
pacitor from this pin to AGND.
LDO output — The voltage at this pin must be less than or equal to the voltage at the VDDA pin.
Bootstrap pin — connect a 100nF minimum capacitor from BST to LX to develop the floating voltage for the
high-side gate drive.
High-side gate drive output
Switching (phase) node
Power ground
Low-side gate drive output
Supply input for the DH and DL gate drives — connect to the same 3.3V or 5V supply used for VDDA.
Power-save programming input — connect a resistor to AGND to set a minimum (ultrasonic) power-save
frequency — float pin to select power-save with no minimum frequency — pull up to VDDA to disable
power-save and select forced continuous mode.
Open-drain Power Good indicator — high impedance indicates the switching regulator output is good. An
external pull-up resistor is required.
Current limit sense pin — used to program the current limit by connecting a resistor from ILIM to LX.
Enable input for switching regulator — logic low disables the switching regulator — logic high enables the
switching regulator.
Analog ground
ON time programming input — set the on-time by connecting through a resistor to AGND.
Enable input for the LDO and VIN UVLO input for the switching regulator — connect ENL to AGND to disable
the LDO — drive to logic high (>3V) to enable the LDO and inhibit VIN UVLO — connect to resistor divider
from VIN to AGND to program the V
Analog ground
IN
UVLO threshold.
11