HEF4521B
24-stage frequency divider and oscillator
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) functions 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 counts 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.
Features and benefits
Wide supply voltage range from 3.0 V to 15.0 V
CMOS low power dissipation
High noise immunity
Low power crystal oscillator operation
Fully static operation
5 V, 10 V, and 15 V parametric ratings
Standardized symmetrical output characteristics
Complies with JEDEC standard JESD 13-B
- ESD protection:
HBM JESD22-A114F exceeds 2000 V
MM JESD22-A115-A exceeds 200 V
Specified from -40 °C to +85 °C
Parametrics
| Type number | VCC (V) | Output drive capability (mA) | Logic switching levels | tpd (ns) | Power dissipation considerations | Tamb (°C) | Package name |
|---|---|---|---|---|---|---|---|
| HEF4521BT | 3.0 - 15 | ± 2.4 | CMOS | 220 | medium | -40~85 | SO16 |
Package
| Type number | Orderable part number, (Ordering code (12NC)) | Status | Marking | Package | Package information | Reflow-/Wave soldering | Packing |
|---|---|---|---|---|---|---|---|
| HEF4521BT | HEF4521BT,653 (933406770653) |
Active | HEF4521BT |
SO16 (SOT109-1) |
SOT109-1 |
SO-SOJ-REFLOW
SO-SOJ-WAVE WAVE_BG-BD-1 |
Not available |
All type numbers in the table below are discontinued.
| Type number | Orderable part number, (Ordering code (12NC)) | Status | Marking | Package | Package information | Reflow-/Wave soldering | Packing |
|---|---|---|---|---|---|---|---|
| HEF4521BT | HEF4521BT,652 (933406770652) |
Withdrawn / End-of-life | HEF4521BT |
SO16 (SOT109-1) |
SOT109-1 |
SO-SOJ-REFLOW
SO-SOJ-WAVE WAVE_BG-BD-1 |
SOT109-1_652 |
Environmental information
| Type number | Orderable part number | Chemical content | RoHS | RHF-indicator |
|---|---|---|---|---|
| HEF4521BT | HEF4521BT,653 | HEF4521BT |
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All type numbers in the table below are discontinued.
| Type number | Orderable part number | Chemical content | RoHS | RHF-indicator |
|---|---|---|---|---|
| HEF4521BT | HEF4521BT,652 | HEF4521BT |
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Documentation (11)
| File name | Title | Type | Date |
|---|---|---|---|
| HEF4521B | 24-stage frequency divider and oscillator | Data sheet | 2023-10-19 |
| AN11051 | Pin FMEA HEF4000 family | Application note | 2019-01-09 |
| 001aae710 | Block diagram: HEF4521BP, HEF4521BT | Block diagram | 2009-11-04 |
| SOT109-1 | 3D model for products with SOT109-1 package | Design support | 2020-01-22 |
| Nexperia_package_poster | Nexperia package poster | Leaflet | 2020-05-15 |
| SO16_SOT109-1_mk | plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.35 mm body | Marcom graphics | 2017-01-28 |
| SOT109-1 | plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.75 mm body | Package information | 2023-11-07 |
| SO-SOJ-REFLOW | Footprint for reflow soldering | Reflow soldering | 2009-10-08 |
| Nexperia_Selection_guide_2023 | Nexperia Selection Guide 2023 | Selection guide | 2023-05-10 |
| SO-SOJ-WAVE | Footprint for wave soldering | Wave soldering | 2009-10-08 |
| WAVE_BG-BD-1 | Wave soldering profile | Wave soldering | 2021-09-08 |
Support
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Models
| File name | Title | Type | Date |
|---|---|---|---|
| SOT109-1 | 3D model for products with SOT109-1 package | Design support | 2020-01-22 |
Ordering, pricing & availability
Sample
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