LM2854MHX-1000/NOPB National Semiconductor, LM2854MHX-1000/NOPB Datasheet - Page 3

• Manufacturer Part Number: LM2854MHX-1000/NOPB
• Description: IC REG 4A SYNC S SWITCH 16ETSSOP
• Manufacturer: National Semiconductor
• Series: PowerWise®, SIMPLE SWITCHER®r
• Type: Step-Down (Buck)r

Specifications of LM2854MHX-1000/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 ~ 5 V
• Current - Output: 4A
• Frequency - Switching: 1MHz
• Voltage - Input: 2.95 ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: LM2854MHX-1000

Pin Descriptions
Pin Number
12,13
2,3,4
5,6,7
EXP
8,9
10
11
14
15
16
1
Exposed
PGND
AGND
Name
PVIN
AVIN
Pad
SW
NC
NC
EN
SS
FB
Reserved for factory use, this pin should be connected to GND to ensure proper operation.
Power ground pins for the internal power switches. These pins should be connected together locally
at the device and tied to the PC board ground plane.
Input voltage to the power switches inside the device. These pins should be connected together at the
device. A low ESR input capacitance should be located as close as possible to these pins.
Reserved for factory use, these pins should be connected to GND to ensure proper operation.
Analog input voltage supply that generates the internal bias. The UVLO circuit derives its input from
this pin also. Thus, if the voltage on AVIN falls below the UVLO threshold, both internal FETs are turned
off. It is recommended to connect PVIN to AVIN through a low pass RC filter to minimize the influence
of input rail ripple and noise on the analog control circuitry. The series resistor should be 1Ω and the
bypass capacitor should be a X7R ceramic type 0.1 µF to 1.0 µF.
Active high enable input for the device. Typically, turn-on threshold is 1.23V with 0.15V hysteresis. An
external resistor divider from PVIN can be used to effectively increase the UVLO turn-on threshold. If
not used, the EN pin should be connected to PVIN.
Switch node pins. This is the PWM output of the internal MOSFET power switches. These pins should
be tied together locally and connected to the filter inductor.
Soft-start control pin. An internal 2 µA current source charges an external capacitor connected between
this pin and AGND to set the output voltage ramp rate during startup. This pin can also be used to
configure the tracking feature.
Quiet analog ground for the internal bias circuitry.
Feedback pin is connected to the inverting input of the voltage loop error amplifier. A 0.8V bandgap
reference is connected to the non-inverting input of the error amplifier.
Exposed metal pad on the underside of the package with a weak electrical connection to PGND. It is
recommended to connect this pad to the PC board ground plane in order to improve thermal
dissipation.
3
Description
www.national.com