a4930 Allegro MicroSystems, Inc., a4930 Datasheet

no-image

a4930

Manufacturer Part Number
a4930
Description
A4930 Single Phase Fan Pre-driver
Manufacturer
Allegro MicroSystems, Inc.
Datasheet
Features and Benefits
▪ Synchronous rectification for low power dissipation
▪ Drives four N-channel MOSFETs
▪ Internal UVLO and thermal shutdown circuitry
▪ Hall element input
▪ PWM current limiting
▪ Dead time protection
▪ FG output
▪ RD output
▪ Lock detect protection
▪ High V
▪ Soft start
Package: 28-pin QFN with exposed
thermal pad (suffix ET)
4930-DS
8.2 kΩ
Hall
5 kΩ
500 Ω
VREG5
BB
0.1 μF
absolute maximum
Hall
Hall
0.1 μF
470 pF
0.1 μF
51 kΩ
VREG5
CPWM
SMIN
CDEL
PWM
FGO
CLD
SIN
RD
HP
HN
1.5v
3.5v
5V
Lock Detect
Approximate size
0.1 μF
8V
Control
Functional Block Diagram
Logic
CHARGE PUMP
VCP
0.1 μF
DRIVE
GATE
VREG8
vref
/5
Description
Designed for pulse width modulated (PWM) current control
of single phase brushless fans, the A4930 minimizes external
component count and integrates all the key features required
for high-current fans. Internal synchronous rectification control
circuitry is provided to improve power dissipation in the
external MOSFETs during PWM operation. Internal circuit
protection includes thermal shutdown with hysteresis, rotor
lock, and dead time protection.
The A4930 is supplied in a 0.90 nominal overall height,
5 mm × 5 mm, 28-pin QFN with exposed thermal pad, (suffix
ET). It is lead (Pb) free with 100% matte tin leadframe
plating.
Single Phase Fan Pre-Driver
SENSE
GHA
GHB
VREF
VCP
VBB
GLB
GLA
SA
SB
SS
0.1 μF
1.24 kΩ
0.47 μF
0.22 μF
5 kΩ
VREG5
VREG5
Hall
Fan
HP HN
100 mΩ
A4930
10 μF
+12V

Related parts for a4930

a4930 Summary of contents

Page 1

... MOSFETs during PWM operation. Internal circuit protection includes thermal shutdown with hysteresis, rotor lock, and dead time protection. The A4930 is supplied in a 0.90 nominal overall height × 5 mm, 28-pin QFN with exposed thermal pad, (suffix ET lead (Pb) free with 100% matte tin leadframe plating ...

Page 2

... A4930 Selection Guide Part Number A4930METTR-T 1500 pieces per 7-in. reel Absolute Maximum Ratings Characteristic Load Supply Voltage Hall Input Logic Input Voltage Range Operating Temperature Range Junction Temperature Storage Temperature Range may require derating at maximum conditions THERMAL CHARACTERISTICS Characteristic Package Thermal Resistance *Additional thermal information available on Allegro website ...

Page 3

... A4930 ELECTRICAL CHARACTERISTICS Characteristic Load Supply Voltage Range Motor Supply Current VREG5 VREG5 Current Limit VREG5 Load Regulation Control Logic Logic Input Voltage PWM Pin Input Current Other Logic Pin Input Current Gate Drive High Side Gate Drive Output Low Side Gate Drive Output ...

Page 4

... A4930 1 ELECTRICAL CHARACTERISTICS Characteristic VBB Undervoltage Lockout Enable Threshold VBB Undervoltage Lockout Hysteresis VCP Undervoltage Lockout Enable Threshold Lock Detect On-Time Lock Detect Off-Time Hall Logic Hall Input Current Common Mode Input Range AC Input Voltage Range Hall Threshold Hysteresis Width Pulse Reject Filter ...

Page 5

... If this feature is not utilized, the SS pin should be left open. Synchronous Rectification load current recirculates. The A4930 synchronous rectification feature turns on the appropriate MOSFETs during current decay, and effectively shorts out the body diodes of the low R driver ...

Page 6

... GND. A resistor connected between this pin and GND sets CDEL the level at which the A4930 switches to slow decay mode in advance of the Hall zero crossing as shown here: The resistor should 100 kΩ. If this feature is not used, the CDEL pin should be pulled ...

Page 7

... Locate the A4930 to minimize the length of the GHx/GLx/Sx traces to the power stage. • Connect the GND pins of the A4930 to the exposed pad. Use vias under the IC case to connect the exposed pad to the ground plane on the opposite face of the PCB. ...

Page 8

... A4930 Terminal List Number Name 1 VREG5 Regulator decoupling terminal 2 CLD Capacitor to set Lock Detect Time output, fan speed indicator (open drain) RD output, high for locked rotor condition (open 4 RD drain Hall input positive 6 HN Hall input negative 7 CDEL Commutation delay ...

Page 9

... A4930 Package ET 28-Pin QFN with Exposed Thermal Pad 29X 0.08 C +0.05 0.25 –0.07 +0.20 0.55 –0. Copyright ©2008, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products ...

Related keywords