Texas Instruments 36V, 2A PowerWise® Adjustable Frequency Synchronous Buck Regulator Evaluation Module LM20242EVAL/NOPB LM20242EVAL/NOPB Fiche De Données
Codes de produits
LM20242EVAL/NOPB
VIN
1
FB
SS/TRK
SW
VIN
GND
AGND
SW
EN
VIN
PGOOD
COMP
EP
VCC
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
SW
GND
GND
SW
VIN
RT
BOOT
SNVS534E – OCTOBER 2007 – REVISED MARCH 2013
Connection Diagram
Figure 1. Top View
HTSSOP Package
PIN DESCRIPTIONS
Pin(s)
Name
Description
Application Information
1
SS/TRK
Soft-Start or Tracking control input
An internal 5 µA current source charges an external capacitor to set the
soft-start rate. The PWM can Track to an external voltage ramp with a
low impedance source. If left open, an internal 1 ms SS ramp is
activated.
soft-start rate. The PWM can Track to an external voltage ramp with a
low impedance source. If left open, an internal 1 ms SS ramp is
activated.
2
FB
Feedback input to the error amplifier
This pin is connected to the inverting input of the internal
from the regulated output
transconductance error amplifier. An 800 mV reference is internally
connected to the non-inverting input of the error amplifier.
connected to the non-inverting input of the error amplifier.
3
PGOOD
Power good output signal
Open drain output indicating the output voltage is regulating within
tolerance. A pull-up resistor of 10 k
tolerance. A pull-up resistor of 10 k
Ω
to 100 k
Ω
is recommended if this
function is used.
4
COMP
Output of the internal error amplifier and
The loop compensation network should be connected between the
input to the Pulse Width Modulator
COMP pin and the AGND pin.
5,6,15,16
VIN
Input supply voltage
Nominal operating range: 4.5V to 36V.
7,8,13,14
SW
Switch pin
The drain terminal of the internal Synchronous Rectifier power
NMOSFET and the source terminal of the internal Control power
NMOSFET.
NMOSFET and the source terminal of the internal Control power
NMOSFET.
9,10,11
GND
Ground
Internal reference for the power MOSFETs.
12
AGND
Analog ground
Internal reference for the regulator control functions.
17
BOOT
Boost input for bootstrap capacitor
An internal diode from VCC to BOOT charges an external capacitor
required from SW to BOOT to power the Control MOSFET gate driver.
required from SW to BOOT to power the Control MOSFET gate driver.
18
VCC
Output of the high voltage linear
VCC tracks VIN up to about 7.2V. Above VIN = 7.2V, VCC is regulated
regulator. The VCC voltage is regulated
to approximately 5.5 Volts. A 0.1 µF to 1 µF ceramic decoupling
to approximately 5.5V.
capacitor is required. The VCC pin is an output only.
19
EN
Enable or UVLO input
An external voltage divider can be used to set the line undervoltage
lockout threshold. If the EN pin is left unconnected, a 2 µA pull-up
current source pulls the EN pin high to enable the regulator.
lockout threshold. If the EN pin is left unconnected, a 2 µA pull-up
current source pulls the EN pin high to enable the regulator.
20
RT
Internal oscillator frequency adjust input
Normally biased at 550 mV. An external resistor connected between RT
and AGND sets the internal oscillator frequency.
and AGND sets the internal oscillator frequency.
EP
Exposed
Exposed pad
Exposed metal pad on the underside of the package with a weak
Pad
electrical connection to GND. Connect this pad to the PC board ground
plane in order to improve heat dissipation.
plane in order to improve heat dissipation.
2
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