LT1768IGN Linear Technology, LT1768IGN Datasheet
LT1768IGN
Specifications of LT1768IGN
Available stocks
Related parts for LT1768IGN
LT1768IGN Summary of contents
Page 1
... The LT1768 also has undervoltage lockout, thermal limit, and a shutdown pin that reduces supply current available in a small 16-lead SSOP package. , LTC and LT are registered trademarks of Linear Technology Corporation. Multimode Dimming is a trademark of Linear Technology Corporation. *Patent Pending 33pF ...
Page 2
... SENSE V = 0.75V PROG SENSE V = 0.75V 150mV PROG SENSE PROG (Note 2) (Note 3) (Note ORDER PART NUMBER 16 GATE LT1768CGN LT1768IGN REF 13 FAULT 12 SHDN GN PART 11 R MIN 10 R MARKING MAX 9 PWM 1768 1768I = 100 C 0V 2.5V –100 A, PROG PWM RMAX MIN TYP MAX UNITS ...
Page 3
ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are –100 A, unless otherwise specified. RMIN SYMBOL PARAMETER I PWM Input Bias Current PWM PWM Duty Cycle PWM Frequency V DIO1/2 Positive Voltage DIO1/2 DIO1/2 Negative Voltage V VC ...
Page 4
LT1768 W U TYPICAL PERFOR A CE CHARACTERISTICS V vs Temperature REF 5. –1mA REF 5.08 5.06 5.04 5.02 5.00 4.98 4.96 4.94 4.92 4.90 –50 – 100 125 TEMPERATURE ( C) 1768 G01 ...
Page 5
W U TYPICAL PERFOR A CE CHARACTERISTICS Switching Frequency vs Temperature 400 390 380 370 360 350 340 330 320 310 300 –50 – 100 125 TEMPERATURE ( C) 1768 G10 FAULT Pin Saturation Voltage vs ...
Page 6
LT1768 W U TYPICAL PERFOR A CE CHARACTERISTICS VC Clamp Voltage vs Temperature 3. 500 A VC 3.85 3.80 3.75 3.70 3.65 3.60 3.55 3.50 3.45 3.40 50 –50 – 100 125 TEMPERATURE ( C) ...
Page 7
PIN FUNCTIONS PGND (Pin 1): The PGND pin is the high current ground path. High switching current transients and lamp current flow through the PGND pin. DIO1/DIO2 (Pins 3/2): Each DIO pin is the common connection between ...
Page 8
LT1768 PIN FUNCTIONS R (Pin 10): The R pin outputs a regulated voltage MAX MAX of 1.25V that loaded with an external resistor. The current through the external resistor sets the maximum lamp current. ...
Page 9
W BLOCK DIAGRA REF IN UNDERVOLTAGE SHDN 12 LOCKOUT THERMAL SHUTDOWN V 14 REF R 11 1.26V I MIN RMIN R MAX 10 I RMAX 1.25V MODE PROG 8 V PWM PWM 9 1V ...
Page 10
LT1768 U U APPLICATIONS INFORMATION The current mode pulse width modulation produces an average current in inductor L1 proportional to the VC voltage. Inductor L1 then acts as a switched mode current source for a current driven Royer class converter ...
Page 11
U U APPLICATIONS INFORMATION per lamp to 1mA for all PROG voltages but limits the dimming ratio to 6:1. Trace B in Figures 3a and 3b shows Figure 1’s CCFL current waveform operating at 1mA in PWM mode. Maximum current ...
Page 12
LT1768 U U APPLICATIONS INFORMATION and is dependant on the operating mode. For dual lamp displays, the transfer function for minimum current mode ( equal to 10A/A, and for maximum current DIO RMIN mode ( ...
Page 13
U U APPLICATIONS INFORMATION voltage and DIO lines can cause enough current flow to fool the open lamp detection. In situations where coupling can’t be avoided, resistors can be added from the DIO pins to ground to increase the open ...
Page 14
LT1768 U U APPLICATIONS INFORMATION GATE The LT1768 has a single high current totem pole output stage. This output stage is capable of driving up to 1.5A of output current. Cross-conduction current spikes in the totem pole output have been ...
Page 15
... IN Applications Support Linear Technology invests an enormous amount of time, resources, and technical expertise in understanding, de- signing and evaluating backlight solutions for systems designers. The design of an efficient and compact back- light system is a study of compromise in a transduced electronic system ...
Page 16
LT1768 U TYPICAL APPLICATIONS 16 DC Intensity Control V REF R1 100k PROG POT LT1768 AGND 1768 TA04 PWM Intensity Control V R1 REF 49.9k 0 – >5V PROG 1kHz PWM C1 LT1768 10 F AGND PWM Intensity Control From ...
Page 17
U TYPICAL APPLICATIONS 2-Wire Serial interface Intensity Control SCL REF PROG SDA V OUT LTC1663 LT1768 GND AGND 1768 TA08 Pushbutton Intensity Control R1 50k S1 CLK1 SHDN V PROG V CLK2 S2 CC LTC1426 AGND V ...
Page 18
LT1768 U TYPICAL APPLICATIONS 18 ...
Page 19
... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
Page 20
... Precision 100 A Full Scale Current DAC www.linear.com C9 33pF X1 LAMP T1 CTX110607 C7 0. 499 Q1A Q1B ZDT1048 ZDT1048 MBRS130LT3 Q2 Si3456DV 100 0.05 1000pF 1768 TA09 30V, CCFL Switch: 1.25A, LCD Switch: 625mA, sn1768 1768fs LT/TP 0901 2K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2000 ...