BU2879AK

Standard ICs FL tube driver BU2879AK The BU2879AK is a driver IC for fluorescent displays. It is equipped with 26 high-voltage withstand outputs and can display from 11 segments of 15 characters to 16 segments of 8 characters. This IC is equipped with a key scanning function, and general-purpose input pins, and is ideal for front panels in VTRs and other equipment. A serial interface allows functions to be controlled from a microcomputer. •Applications VCRs •Features 1) High withstanding voltage output. 2) Display modes: 11S × 15G ~ 16S × 8G. 3) Variable display luminance (7 steps). 4) 3-wire serial interface. 5) Key scanning function (6 × 4). 6) Internal pull-down resistance (high voltage withstand output). 7) QFP 44 package. •Absolute maximum ratings (Ta = 25°C, V Parameter Applied voltage 1 Applied voltage 2 Input voltage Power dissipation Operating temperature Storage temperature Symbol VDD VEE VIN Pd Topr Tstg SS = 0V) Limits – 0.3 ~ + 7.0 VDD + 0.3 ~ VDD – 40 – 0.3 ~ VDD + 0.3 850∗ – 25 ~ + 75 – 55 ~ + 125 Unit V V V mW °C °C Note) Operation is not guaranteed at these values. Note) Power dissipation is reduced by 8.5mW for each increase in Ta of 1°C over 25°C. ∗ When mounted on a 70 × 70 × 1.6mm glass epoxy board •Recommended operating conditions (Ta = 25°C, V Parameter Operating power supply voltage 1 Operating power supply voltage 2 Symbol VDD VEE SS = 0V) Min. 4.5 Typ. 5.0 VDD – 35 Max. 5.5 VDD – 0 Unit V V VDD – 37 1 Standard ICs BU2879AK •Block diagram CS SCK SI SO VSS OSC VDD 8bit shift-REG. OSC CONTROL LOGIC 16bit latch SW4 4bit data G1 SW1 16bit × 15word DISPLAY DATA RAM K4 KEY DATA latch (4 × 6) K1 GRID Driver G10 SEGMENT Driver S / G Driver S1 S11 S12 / G15 S16 / G11 VEE 2 Standard ICs BU2879AK •Pins descriptions Pin No. 14, 38 44 7, 43 6 5 8 9 15 ~ 25 27 42 ~ 39, 37 ~ 32 26, 28 ~ 31 10 ~ 13 Pin VDD OSC VSS SI SO SCK CS S1 ~ S11 VEE G1 ~ G10 S12 / G15 S16 / G11 K1 ~ K4 ~ SW1 ~ SW4 Name Power supply pin 1 Oscillation pin Ground pin Serial data input Serial data output Serial clock input Serial chip select High-voltage withstand output pin for segment Power supply pin 2 High-voltage withstand output pin for grid High-voltage withstand output pin for segment / grid Key data input pin I/O Input Function Connected to system power supply. Input / output Capacitor connection pin for oscillation Input Input Output Input Input Output Input Output Connected to system ground. Serial data input starting from MSB Serial data output starting from MSB; output is Nch open drain. Serial data read at rising edge. Serial initialization when LOW, valid at HIGH. Output pin for segment; output is Pch open drain + pull-down resistance. Pull-down resistance connection for FLP driver output. Output pin for grid; output is Pch open drain + pull-down resistance. Used to switch output between segment and grid; output is Pch open drain + pull-down resistance. Data input pin for key scanning. General-purpose input pin; input data can be transmitted serially to microcomputer. DD Output Input 1~4 General-purpose input pin Input •Electrical characteristics (unless otherwise noted, Ta = 25°C, V Parameter Supply current Input threshold voltage Input current OSC oscillation frequency Segment output current Grid output current Leakage current when OFF Output pull-down resistance Maximum operating frequency 〈Serial transmission〉 Input data hold Input data setup Output data delay Input clock cycle Input clock "H" width TSH TSS TD TSCYC TSW 0.16 0.16 — 0.5 40 — — — — — — — 0.3 — 60 µs µs µs µs % Symbol IDD VIN IIN FOSC IOseg IOgrd IOFF RD FMAX Min. — 1.5 — 130 6 18 — 35 — Typ. — — — 200 — — — 70 — Max. 5 3.5 10 300 — — 10 140 1 Unit mA V µA kHz mA mA µA kΩ MHz = 5V, VSS = 0V, VDD – VEE = 35V) Conditions Measurement circuit 44-pin attachment, at 1000pF oscillation Pins 1 to 4, 6, 8, 9 to 13 Pins 1 to 4, 6, 8, 9 to 13 44-pin attachment, at 1000pF oscillation Pins 15 to 26, 28 to 31, VO = VDD – 2V∗ Pins 26, 28 to 37, 39 to 42, VO = VDD – 2V∗ Pins 15 to 26, 28 to 37, VO = VDD – VEE Pins 15 to 26, 28 to 37 Design guarantee value Fig.1 Fig.4 Fig.2 Fig.3 Fig.2 Fig.2 Fig.2 Fig.2 Fig.3 — — — — — — — — — At minimum input clock cycle ∗ For the high voltage withstand output pins for the segment / grid of pins 26 and 28 to 31, when segment output is specified, segment output current is output, and when grid output is specified, grid current is output. 3 Standard ICs BU2879AK •Measurement circuits A VEE 1000p OSC VSS VSS n VDD VEE VDD n = Test pin A V Fig.1 Fig.2 VEE 1000p OSC VSS VDD G1 Monitor VEE VDD VSS Fig.3 Fig.4 •Electrical characteristic curves “H” GRID OUTPUT CURRENT: IOHgrd (mA) 3.8 3.7 3.6 3.5 3.4 3.3 3.2 54 50 46 42 38 34 30 “H” SEGMENT OUTPUT CURRENT: IOHseg (mA) 16 15 14 13 12 11 10 25 75 CIRCUIT CURRENT: IDD (mA) – 25 25 75 – 25 – 25 25 75 TEMPERATURE: Ta (°C) TEMPERATURE: Ta (°C) TEMPERATURE: Ta (°C) Fig. 5 Supply current temperature characteristics Fig. 6 “H” grid output current temperature characteristics Fig.7 “H” segment output current temperature characteristics 4 Standard ICs BU2879AK •External dimensions (Units: mm) 14.0 ± 0.3 10.0 ± 0.2 33 23 22 14.0 ± 0.3 10.0 ± 0.2 34 44 12 1 2.15 ± 0.1 0.05 11 0.15 ± 0.1 0.8 0.35 ± 0.1 0.15 QFP44 1.2 5