AS1118 64 LED Driver for Mobile Applications with Error Detection 1 General Description 2 Key Features 10MHz SPI-Compatible Interface The AS1118 is a compact LED driver for 64 single LEDs or 8 digits of 7-segments. The devices can be pro- Open and Shorted LED Error Detection grammed via an SPI compatible 3-wire interface. Every - Global or Individual Error Detection segment can be individually addressed and updated Hexadecimal- or BCD-Code for 7-Segment Displays separately. Only one external resistor (RSET) is required 200nA Low-Power Shutdown Current (typ data to set the current. LED brightness can be controlled by retained) analog or digital means. The devices include an inte- Individual Digit Brightness Control grated BCD code-B/HEX decoder, multiplex scan cir- cuitry, segment and display drivers, and a 64-bit Digital and Analog Brightness Control memory. Internal memory stores the shift register set- Display Blanked on Power-Up tings, eliminating the need for continuous device repro- Drive Common-Cathode LED Displays gramming. Supply Voltage Range: 2.7V to 5.5V Table 1. Available Products Software and Hardware Reset Devices RESET Input Interfaces Optional External Clock AS1115 no IC Package: TQFN(4x4)-24 AS1116 no SPI AS1117 yes IC 3 Applications AS1118 yes SPI The AS1118 is ideal for seven-segment or dot matrix dis- , Additionally the AS1118 offers a detailed error diagnostic plays in mobile applications, public information displays mode for easy and fast production testing in critical at subway, train or bus stations, at airports and also at applications. The AS1118 features a low shutdown cur- displays in public transportation like buses or trains, per- rent of typically 200nA, and an operational current of sonal electronic and toys. typically 350A. The number of digits can be pro- grammed, the devices can be reset by software, and an external clock is also supported. The device is available in a TQFN(4x4)-24 package. Figure 1. AS1118 - Typical Application Diagram 8 DIG0 to SEGA-DP DIG7 VDD 8 8 8 8 VDD 2.7V to 5.5V 9.53k GND ISET AS1118 AS1118 AS1118 SDI SDO SDI SDO SDI SDO I/O LD LD LD SCL RESETN RESETN RESETN SCL SCL I/O P I/O I/O I/O Diagnostic readback: open & shorted LEDs www.ams.com/LED-Driver-IC2/AS1118 Revision 1.02 1 - 20AS1118 Datasheet - P in o ut 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) 24 23 22 21 20 19 1 18 DIG2 SEG E DIG3 2 17 SEGC GND 3 16 VDD AS1118 DIG4 4 15 SEGG DIG5 5 14 SEGB RESETN 6 13 SEGF 7 8 9 10 11 12 Pin Descriptions Table 2. Pin Descriptions Pin Name TQFN(4x4)-24 Description Serial-Data Input. Data is loaded into the internal 16-bit shift register on the 22 SDI rising edge of pin SCL. Digit Drive Lines. Eight digit drive lines that sink current from the display 1, 2, 4, 5, 7, 8, 23, DIG0:DIG7 24 cathode. 3 Ground. GND Load. Serial Data is loaded into the shift register while this pin is low. The last 9 LD 16 bits of serial data are latched on the rising edge of this pin. Reset Input. Pull this pin to low to resest all registers (set to default values) and 6 RESETN to put the device into shutdown. Set Segment Current. Connect to VDD or a reference voltage through RSET to ISET 10 set the peak segment current (see Selecting RSET Resistor Value and Using External Drivers on page 15). Serial-Clock Input. 10MHz maximum rate. Data is shifted into the internal shift SCL 11 register on the rising edge of this pin. Data is clocked out of pin SDO on the rising edge of this pin. Seven Segment and Decimal Point Drive Lines. 8 seven-segment drives and SEGA:SEGG, 12-15, SEGDP 17-20 decimal point drive that source current to the display. Positive Supply Voltage. Connect to +2.7V to +5.5V supply. Bypass this pin to 16 VDD GND with a 10F and a 0.1F capacitor to avoid power supply ripple. Serial-Data Output. The data into pin SDI is valid at pin SDO 16 clock cycles 21 SDO later. This pin is used to daisy-chain several devices and is never high- impedance. Exposed Pad. This pin also functions as a heat sink. Solder it to a large pad or Exposed Pad to the circuit-board ground plane to maximize power dissipation. www.ams.com/LED-Driver-IC2/AS1118 Revision 1.02 2 - 20 DIG6 DIG1 DIG7 DIG0 LD SDI ISET SDO SCL SEGD SEGA SEGDP