HEF4521B(2009) 查看數據表（PDF） - NXP Semiconductors.

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HEF4521B
(Rev.:2009)

24-stage frequency divider and oscillator

NXP Semiconductors. 

HEF4521B

24-stage frequency divider and oscillator

Rev. 05 — 5 November 2009

Product data sheet

1. General description

The HEF4521B consists of a chain of 24 toggle flip-flops with an overriding asynchronous

master reset input (MR), and an input circuit that allows three modes of operation. The

single inverting stage (A2 to Y2) will function as: a crystal oscillator, an input buffer for an

external oscillator or in combination with A1 as an RC oscillator. The crystal oscillator

operates in Low-power mode when pins VSS1 and VDD1 are supplied via external resistors.

Each flip-flop divides the frequency of the previous flip-flop by two, consequently the

HEF4521B will count up to 224 = 16777216. The counting advances on the HIGH-to-LOW

transition of the clock (A2). The outputs from each of the last seven stages (218 to 224) are

available for additional flexibility.

It operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS

(usually ground). Unused inputs must be connected to VDD, VSS, or another input. It is

also suitable for use over the full industrial (−40 °C to +85 °C) temperature range.

2. Features

I Low power crystal oscillator operation

I Fully static operation

I 5 V, 10 V, and 15 V parametric ratings

I Standardized symmetrical output characteristics

I Operates across the full industrial temperature range −40 °C to +85 °C

I Complies with JEDEC standard JESD 13-B

3. Applications

I Industrial

4. Ordering information

Table 1. Ordering information

All types operate from −40 °C to +85 °C.

Type number

Package

Name

Description

HEF4521BP

DIP16

plastic dual in-line package; 16-leads (300 mil)

HEF4521BT

SO16

plastic small outline package; 16 leads; body width 3.9 mm

Version

SOT38-4

SOT109-1

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