General Description
The RTQ9297-QT includes a high-performance step-up DC-DC converter that provides a regulated supply voltage for active-matrix thin-film transistor (TFT) liquid-crystal displays (LCDs).
The Boost Converter incorporates current mode, fixed- frequency, pulse-width modulation (PWM) circuitry with a built-in N-Channel power MOSFET to achieve high efficiency and fast transient response.
The RTQ9297-QT is available in a WDFN-10SL 3x3 package.
Performance Specification Summary
Summary of the RTQ9297GQW-QT Evaluation Board performance specification is provided in Table 1. The ambient temperature is 25°C.
Table 1. RTQ9297GQW-QT Evaluation Board Performance Specification Summary
|
Specification
|
Symbol
|
Test Conditions
|
Min
|
Typ
|
Max
|
Unit
|
|
Input Voltage Range
|
VDD
|
VAVDD < 18V
|
2.6
|
--
|
5.5
|
V
|
|
18V < VAVDD < 24V
|
4
|
--
|
5.5
|
|
Output Voltage Range
|
VAVDD
|
|
VDD
|
--
|
24
|
V
|
|
Undervoltage Lockout Threshold
|
VUVLO
|
VDD rising
|
2.17
|
2.4
|
2.55
|
V
|
|
Hysteresis
|
--
|
50
|
240
|
mV
|
|
Shutdown Current
|
ISHDN
|
EN = GND, VlN = 5V
|
--
|
0.1
|
10
|
µA
|
|
Oscillator Frequency
|
fOSC
|
FREQ = GND
|
450
|
640
|
800
|
kHz
|
|
FREQ = VlN
|
900
|
1240
|
1500
|
|
Maximum Duty Cycle
|
|
|
87
|
90
|
95
|
%
|
|
Feedback Regulation Voltage
|
VFB
|
|
1.22
|
1.24
|
1.26
|
V
|
|
TA = full range
|
-3
|
--
|
2
|
%
|
Power-up Procedure
Suggestion Required Equipments
- RTQ9297GQW-QT Evaluation Board
- DC power supply capable of at least 5V and 7A
- Electronic load capable of 3A
- Oscilloscope
Quick Start Procedures
The Evaluation Board is fully assembled and tested. Follow the steps below to verify board operation. Do not turn on supplies until all connections are made. When measuring the output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the output voltage ripple by touching the probe tip and ground ring directly across the last output capacitor.
Proper measurement equipment setup and follow the procedure below.
1) With power off, connect the power supply for VIN and GND pins.
2) With power off, Use Jumper to pull high FREQ and SHDN pins.
3) With power off, connect the electronic load between the VOUT and nearest GND pins.
4) Turn on the power supply at the input. Make sure that the input voltage does not exceeds 5.5V on the Evaluation Board.
5) Check for the proper output voltage using a voltmeter.
6) Once the proper output voltage is established, adjust the load within the operating ranges and observe the output voltage regulation, ripple voltage, efficiency and other performance.
Detailed Description of Hardware
Headers Description and Placement
Carefully inspect all the components used in the EVB according to the following Bill of Materials table, and then make sure all the components are undamaged and correctly installed. If there is any missing or damaged component, which may occur during transportation, please contact our distributors or e-mail us at evb_service@richtek.com.
Test Points
The EVB is provided with the test points and pin names listed in the table below.
|
Test Point/
Pin Name
|
Function
|
|
VOUT
|
Output of boost converter.
|
|
GND
|
Power ground.
|
|
FREQ
|
Boost frequency selection.
|
|
VIN
|
Power supply input.
|
|
SHDN
|
Enable control input (active high).
|
Bill of Materials
|
Reference
|
Count
|
Part Number
|
Value
|
Description
|
Package
|
Manufacturer
|
|
U1
|
1
|
RTQ9297GQW-QT
|
RTQ9297GQW-QT
|
Step-Up DC-DC Converter
|
WDFN-10SL 3x3
|
RICHTEK
|
|
C2
|
1
|
0603B102K500CT
|
1nF
|
Capacitor, Ceramic
50V/X5R
|
0603
|
WALSIN
|
|
C7
|
1
|
0603B333K500CT
|
33nF
|
Capacitor, Ceramic
25V/X7R
|
0603
|
WALSIN
|
|
CIN0
|
1
|
0603X105K250CT
|
1µF
|
Capacitor, Ceramic
25V/X5R
|
0603
|
WALSIN
|
|
CIN1,
CIN2
|
2
|
EMK316AB7106KL-T
|
10µF
|
Capacitor, Ceramic
16V/X7R
|
1206
|
TAIYO YUDEN
|
|
COUT1,
COUT2,
COUT3
|
3
|
MSAST31LAB7106KTNA01
|
10µF
|
Capacitor, Ceramic
25V/X7R
|
1206
|
TAIYO YUDEN
|
|
D1
|
1
|
SK34
|
100V/3A
|
Schottky Diodes
|
|
PANJIT
|
|
L1
|
1
|
LSXNH8080YBL4R7NJG
|
4.7µH
|
Power Inductor
|
8x8mm
|
TAIYO YUDEN
|
|
R0
|
1
|
WR06X000 PTL
|
0
|
Resistor, Chip
0603
|
0603
|
WALSIN
|
|
R1
|
1
|
RTT031693FTP
|
169k
|
Resistor, Chip
0603
|
0603
|
RALEC
|
|
R2
|
1
|
RTT033092FTP
|
30.9k
|
Resistor, Chip
0603
|
0603
|
RALEC
|
|
R3
|
1
|
WR06X5602FTL
|
56
|
Resistor, Chip
0603
|
0603
|
WALSIN
|
Typical Applications
EVB Schematic Diagram
1. The capacitance values of the input and output capacitors will influence the input and output voltage ripple.
2. MLCC capacitors have degrading capacitance at DC bias voltage, and especially smaller size MLCC capacitors will have much lower capacitance.
Measure Result
|
Efficiency vs. Load Current
|
Efficiency vs. Load Current
|
|
|
|
|
Output Voltage vs. Load Current
|
Output Voltage vs. Load Current
|
|
|
|
|
Output Voltage vs. Input Voltage
|
Output Voltage vs. Input Voltage
|
|
|
|
|
Switching Frequency vs. Temperature
|
Reference Voltage vs. Temperature
|
|
|
|
|
Start Up
|
Start Up
|
|
|
|
|
Load Transient Response
|
Load Transient Response
|
|
|
|
Evaluation Board Layout
Figure 1. Top View
Figure 2. Bottom View