HEF4521B_09 Datasheet, PDF (1/17 Pages) NXP Semiconductors – 24-stage frequency divider and oscillator

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 V_SS1 and V_DD1 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 V_DD power supply range of 3 V to 15 V referenced to V_SS
(usually ground). Unused inputs must be connected to V_DD, V_SS, 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