Document
tm TE CH
Preliminary T8322AD
PWM Control 1500mA Step-Down Converter
FEATURES
• Wide Input Voltage Range: 4.5V to 30V • LED Output Current Up to 1500mA • Soft-start • Single pin on/off and brightness control
using DC voltage or PWM • High efficiency (up to 97%) • Up to 1MHz switching frequency • Typical 5% output current accuracy •SOP-8 Lead-free Package
Applications
• LED/Display Back Light Driver • Lightings • Portable Communication Devices • Handheld Electronics
GENERAL DESCRIPTION
The T8322AD is a continuous mode inductive step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device operates from an input supply between 4.5V and 30V and provides an externally adjustable output current of up to 1500mA. Depending upon supply voltage and external components, this can provide up to 24 watts of output power. The T8322AD includes the output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current. The T8322AD is available in SOP-8 Lead-free package.
PART NUMBER EXAMPLES
PART NO. T8322AD
PACKAGE SOP-8
TM Technology, Inc. reserves the right
P. 1
to change products or specifications without notice.
Publication Date: Sep. 2014 Revision:C
tm TE CH
PIN ARRANGEMENT(Top view)
Preliminary T8322AD
PIN DESCRIPTION
Symbol LX GND EN
ADJ
ISENSE VIN
SOP-8
Description
3,4 Drain of NDMOS switch
5.6 Ground
1 Enable control signal, H: Active, L: Power Down
ADJ
Multi-function Dimming and brightness control pin:
Leave floating for normal operation.(VADJ=VREF=1.25V giving nominal
2
average output current IOUTnom = 0.1/RS) Drive with DC voltage(0.25V < VADJ <1.25V) to adjust output current from
0% to 100% of IOUTnom
TTL PWM Dimmering input MAX ADJ frequency 20KHz.
8
Connect resistor Rs from this pin to VIN to define nominal average output current IOUTnom=0.1/Rs
Input voltage (4.5V to 30V).
7 Decouple to ground with 47uF or higher X7R ceramic capacitor close to
device.
TM Technology, Inc. reserves the right
P. 2
to change products or specifications without notice.
Publication Date: Sep . 2014 Revision:C
tm TE CH
ABSOLUTE MAXIMUM RATINGS
Parameter Voltage on input pin relative to GND ISENSE pin Voltage EN pin &ADJ pin Voltage Operating junction Temperature Rang Operating Temperature Rang Maximum Soldering Temperature (at lead, 10sec) Storage Temperature Rang Power Dissipation, PD @ TA=25℃ Package Thermal Resistance, θJA
Preliminary T8322AD
Symbol VIN
Tj TA TLEAD TS SOP-8 SOP-8
Value -0.3 to +40 -5 to +0.3 -0.3 to +6 -40 to 150 -40 to 105
300 -65 to +150
0.8 50
Unit V V V ℃ ℃ ℃ ℃ W
℃/W
Electrical Characteristics
(TA=-40 to 85℃ unless otherwise noted. Typical values are at TA=25℃, VDD=24V)
Symbol
Description
Conditions
Min. Typ. Max. Unit
VIN Input voltage
UVLO Under Voltage lock out VIRU Internal regulator start-up threshold VIRD Internal regulator shutdown
VIN r.