Datasheet MAX7219, MAX7221 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Serially Interfaced, 8-Digit, LED Display Drivers |
| Pages / Page | 15 / 5 — Pin Description. PIN. NAME. FUNCTION. Functional Diagram |
| File Format / Size | PDF / 1.4 Mb |
| Document Language | English |
Pin Description. PIN. NAME. FUNCTION. Functional Diagram
Model Line for this Datasheet
Text Version of Document
MAX7219/MAX7221 Serially Interfaced, 8-Digit LED Display Drivers
Pin Description PIN NAME FUNCTION
1 DIN Serial-Data Input. Data is loaded into the internal 16-bit shift register on CLK’s rising edge. 2, 3, 5–8, Eight-digit drive lines that sink current from the display common cathode. The MAX7219 pulls 10, 11 DIG 0–DIG 7 the digit outputs to V+ when turned off. The MAX7221’s digit drivers are high-impedance when turned off. 4, 9 GND Ground. Both GND pins must be connected. LOAD (MAX7219) Load-Data Input. The last 16 bits of serial data are latched on LOAD’s rising edge. 12 CS Chip-Select Input. Serial data is loaded into the shift register while CS is low. The last 16 bits of (MAX7221) serial data are latched on CS’s rising edge. Serial-Clock Input. 10MHz maximum rate. On CLK’s rising edge, data is shifted into the internal 13 CLK shift register. On CLK’s falling edge, data is clocked out of DOUT. On the MAX7221, the CLK input is active only while CS is low. 14–17, SEG A–SEG G, Seven Segment Drives and Decimal Point Drive that source current to the display. On the 20–23 DP MAX7219, when a segment driver is turned off it is pulled to GND. The MAX7221 segment drivers are high-impedance when turned off. 18 ISET Connect to VDD through a resistor (RSET) to set the peak segment current (Refer to Selecting RSET Resistor and Using External Drivers section). 19 V+ Positive Supply Voltage. Connect to +5V. 24 DOUT Serial-Data Output. The data into DIN is valid at DOUT 16.5 clock cycles later. This pin is used to daisy-chain several MAX7219/MAX7221’s and is never high-impedance.
Functional Diagram
SEG A–SEG G, DP DIG 0–DIG 7 SEGMENT DRIVERS DIGIT DRIVERS 8 8 SHUTDOWN REGISTER CODE B V+ MODE REGISTER INTENSITY ROM WITH BYPASS INTENSITY REGISTER PULSE- WIDTH R SCAN-LIMIT REGISTER MODULATOR SET 8 SEGMENT DISPLAY-TEST REGISTER CURRENT 8x8 REFERENCE DUAL-PORT MULTIPLEX SRAM SCAN ADDRESS CIRCUITRY 8 8 REGISTER LOAD (CS) DECODER 4 DIN D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 DOUT CLK (LSB) (MSB) ( ) MAX7221 ONLY www.maximintegrated.com Maxim Integrated │ 5
Pin Description PIN NAME FUNCTION
1 DIN Serial-Data Input. Data is loaded into the internal 16-bit shift register on CLK’s rising edge. 2, 3, 5–8, Eight-digit drive lines that sink current from the display common cathode. The MAX7219 pulls 10, 11 DIG 0–DIG 7 the digit outputs to V+ when turned off. The MAX7221’s digit drivers are high-impedance when turned off. 4, 9 GND Ground. Both GND pins must be connected. LOAD (MAX7219) Load-Data Input. The last 16 bits of serial data are latched on LOAD’s rising edge. 12 CS Chip-Select Input. Serial data is loaded into the shift register while CS is low. The last 16 bits of (MAX7221) serial data are latched on CS’s rising edge. Serial-Clock Input. 10MHz maximum rate. On CLK’s rising edge, data is shifted into the internal 13 CLK shift register. On CLK’s falling edge, data is clocked out of DOUT. On the MAX7221, the CLK input is active only while CS is low. 14–17, SEG A–SEG G, Seven Segment Drives and Decimal Point Drive that source current to the display. On the 20–23 DP MAX7219, when a segment driver is turned off it is pulled to GND. The MAX7221 segment drivers are high-impedance when turned off. 18 ISET Connect to VDD through a resistor (RSET) to set the peak segment current (Refer to Selecting RSET Resistor and Using External Drivers section). 19 V+ Positive Supply Voltage. Connect to +5V. 24 DOUT Serial-Data Output. The data into DIN is valid at DOUT 16.5 clock cycles later. This pin is used to daisy-chain several MAX7219/MAX7221’s and is never high-impedance.
Functional Diagram
SEG A–SEG G, DP DIG 0–DIG 7 SEGMENT DRIVERS DIGIT DRIVERS 8 8 SHUTDOWN REGISTER CODE B V+ MODE REGISTER INTENSITY ROM WITH BYPASS INTENSITY REGISTER PULSE- WIDTH R SCAN-LIMIT REGISTER MODULATOR SET 8 SEGMENT DISPLAY-TEST REGISTER CURRENT 8x8 REFERENCE DUAL-PORT MULTIPLEX SRAM SCAN ADDRESS CIRCUITRY 8 8 REGISTER LOAD (CS) DECODER 4 DIN D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 DOUT CLK (LSB) (MSB) ( ) MAX7221 ONLY www.maximintegrated.com Maxim Integrated │ 5