AL58221Typical Applications Circuit Vled VDD ... ... Chip 1 Chip N VSS VDDOUTA3VDDOUTA3REXT_COUTB3REXT_COUTB3REXT_BOUTC3REXT_BOUTC3REXT_AREXT_AGNDGNDOUTC0OUTC0 DCKI DCKIDCKODCKIDCKO DIN DIDODIDOPin DescriptionsPIN NUMBERPIN NAMEDESCRIPTION External resistors connected between REXT and GND for individual output current 1, 2, 3 REXT_C, REXT_B, REXT_A value setting. 4, 7, 16,19 OUTC[0:3] 5, 8, 17, 20 OUTB[0:3] Constant current outputs 6, 9, 18, 21 OUTA[0:3] 10 GCKI External grayscale clock input for PWM/APDM operation. Clock input terminal for serial data transfer. Data is sampled at both rising edge and 11 DCKI falling edge of DCKI. 12 DCKO Clock output terminal for serial data transfer. 13 DI Serial data input terminal. 14 DO Serial data output terminal. Grayscale clock output 15 GCKO When command data “osc” = ‘L’, GCKO comes from internal osc When command data “osc” = ‘H’, GCKO comes from GCKI 22 NC No connect 23 VDD Supply voltage terminal. 24 GND Ground terminal Equivalent Circuit of Inputs and Outputs1. DI, DCKI terminals2. DO, DCKO, GCKO terminals 3. GCKI terminal VDD VDD VDD IN