Overview
The CD74HC4511, produced by Texas Instruments, is a BCD-to-7 segment latch/decoder/driver integrated circuit. This device is designed to convert Binary Coded Decimal (BCD) inputs into the corresponding 7-segment display outputs. It features four address inputs (D0-D3), an active-low blanking (BL) input, a lamp-test (LT) input, and a latch-enable (LE) input. When the LE input is high, the latches store the BCD inputs, and when LE is low, the latches are disabled, making the outputs transparent to the BCD inputs.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| VCC (Supply Voltage) | V | 2 | - | 6 |
| VIH (High-level input voltage) | V | 2 | - | - |
| VIL (Low-level input voltage) | V | - | - | 0.8 |
| IOH (High level output current) | mA | - | - | 10 (at 6 V) |
| IOL (Low level output current) | mA | - | - | 7.5 (at 4.5 V) |
| ICC (Supply current) | μA | - | - | 160 (at 6 V) |
| tW (Pulse duration, LE low) | ns | 14 | - | 20 (at 6 V) |
| tsu (Setup time, BCD inputs before LE↑) | ns | 10 | - | 15 (at 6 V) |
| th (Hold time, BCD inputs before LE↑) | ns | 3 | - | 3 |
| tpd (Propagation delay time) | ns | 51 | - | 77 (at 6 V, CL = 50 pF) |
Key Features
- Operates over a wide VCC range: 2 V to 6 V for 'HC4511 and 4.5 V to 5.5 V for CD74HCT4511.
- High-output sourcing capability: up to 10 mA at 6 V and up to 7.5 mA at 4.5 V.
- Input latches for BCD code storage.
- Lamp test and blanking capability.
- Balanced propagation delays and transition times.
- Significant power reduction compared to LSTTL logic ICs.
- High noise immunity: NIL or NIH = 30% of VCC at VCC = 5 V for 'HC4511.
- Direct LSTTL input logic compatibility and CMOS input compatibility for CD74HCT4511.
Applications
- Display drivers for 7-segment displays in various electronic devices such as calculators, clocks, and other digital displays.
- BCD-to-7 segment conversion in digital circuits.
- Lamp testing and blanking in display systems.
- General-purpose digital logic applications requiring latch and decoder functions.
Q & A
- What is the primary function of the CD74HC4511?
The primary function of the CD74HC4511 is to convert Binary Coded Decimal (BCD) inputs into the corresponding 7-segment display outputs.
- What is the operating voltage range for the CD74HC4511?
The operating voltage range for the CD74HC4511 is 2 V to 6 V).
- What is the maximum output current sourcing capability of the CD74HC4511 at 6 V?
The maximum output current sourcing capability of the CD74HC4511 at 6 V is up to 10 mA).
- Does the CD74HC4511 have input latches for BCD code storage?
Yes, the CD74HC4511 has input latches for BCD code storage).
- What are the lamp test and blanking capabilities of the CD74HC4511?
The CD74HC4511 has lamp test and blanking capabilities, allowing for testing and control of the display).
- How does the CD74HC4511 handle unused inputs?
All unused inputs of the CD74HC4511 must be held at VCC or GND to ensure proper device operation).
- What is the recommended bypass capacitor for the power supply of the CD74HC4511?
A 0.1-μF capacitor is recommended, and it is acceptable to parallel multiple bypass caps to reject different frequencies of noise).
- What are the thermal metrics for the CD74HC4511 in different packages?
The thermal impedance (RθJA) varies by package: 67°C/W for SOIC, 73°C/W for PDIP, and 108°C/W for TSSOP).
- What are the typical propagation delays for the CD74HC4511?
The typical propagation delays range from 51 ns to 77 ns depending on the load capacitance and VCC).
- Is the CD74HC4511 compatible with LSTTL and CMOS logic?
Yes, the CD74HCT4511 version is compatible with both LSTTL and CMOS input logic).
