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FAN8422G
Floppy Disk Drive Spindle Motor Driver
Features
* Three-phase, full-wave, linear BLDC motor driver * Commutation with only two hall sensors * Generating index signal without an index hall sensor by special rotor magnetization * Built-in soft switching drive circuit * 300/360rpm selectable speed control circuit * Snubberless output drive * Chip enable function * Built-in current limit circuit * Built-in thermal shutdown circuit * Low output saturation voltage * TTL, 5V CMOS compatible digital inputs * Built-in current-mode control circuit (IPEAK: 1A)
Description
The FAN8422G is a monolithic integrated circuit suitable for a three-phase spindle motor driver of floppy disk drive systems. It can make index signals without an index hall sensor by special rotor magnetization.
30-SSOP-375
1
Typical Application
* 3.5-inch floppy disk drive(FDD) spindle motor driver
Ordering Information
Device FAN8422G Package 30-SSOP-375 Operating Temp. 0 ~ 75C
Rev. 1.0.1
(c)2003 Fairchild Semiconductor Corporation
FAN8422G
Pin Assignments
FG INPUT(-) AGC INDEX PULSE WIDTH VOLTAGE REGULATOR INDEX BURST INDEX OUTPUT CE SIGNAL GROUND SIGNAL GROUND FG ZERO CROSS FG OUTPUT RPM SELECT CHARGE PUMP OUTPUT OSC INPUT NC
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
FG INPUT(+) HALL BIAS CURRENT DETECTION1 V INPUT(-) V INPUT(+) U PHASE OUTPUT V PHASE OUTPUT SIGNAL GROUND W PHASE OUTPUT NC U INPUT(+) U INPUT(-) CURRENT DETECTION2 VCC PHASE COMPENSATION
FAN8422G
2
FAN8422G
Pin Definitions
Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Pin Name FG_INPUT (-) AGC INDEX PULSE WIDTH VOLTAGE REGULATOR INDEX BURST INDEX OUTPUT CE SIGNAL GROUND SIGNAL GROUND FG ZERO CROSS FG OUTPUT RPM SELECT CHARGE PUMP OUTPUT OSC INPUT NC PHASE COMPENSATION VCC CURRENT DETECTION2 U INPUT (-) U INPUT (+) NC W PHASE OUTPUT SIGNAL GROUND V PHASE OUTPUT U PHASE OUTPUT V INPUT (+) V INPUT (-) CURRENT DETECTION1 HALL BIAS FG INPUT (+) I/O I I O O O O I O O I O I I I I I O O O I I I I I Pin Function Description Negative Input Pin FG Signal Amp. Automatic Gain Control Input Pin Index Pulse Width Detection Pin Voltage Generator Output Pin Index Pulse Width Detection Pin Index Pulse Output Pin Chip Enable (Active Low) Signal Ground Signal Ground FG Signal Zero Cross Detection Pin FG Signal Output Pin RPM Selection Pin (L: 300, H: 360rpm) Charge Pump Output Pin 1MHz Oscillation Input Pin No Connection Phase Compensation Cap. Connection Pin 5V Power Supply Pin Over Current Detection Pin Negative Input Pin of U Phase Amp Positive Input Pin of U Phase Amp No Connection W Phase Output Pin Signal Ground V Phase Output Pin U Phase Output Pin Positive Input Pin of V Phase Amp Negative Input Pin of V Phase Amp Over Current Detection Pin Hall Sensor Bias Input Pin Positive Input Pin of FG Signal Amp
3
FAN8422G
Internal Block Diagram
CURRENT CURRENT DETECTION2 DETECTION1 18 28
VCC 17
U INPUT(+) 20 U INPUT(-) 19 V INPUT(+) 26 V INPUT(-) 27 AGC 2
+ U_AMP - + V_AMP -
U_OUT
25
U PHASE OUTPUT
Output control
V_OUT
24
V PHASE OUTPUT
AGC W_OUT 22 W PHASE OUTPUT
HALL BIAS 29
Start-up
Hall zero-cross TSD
CE
7
CE CON_AMP 1.3V - + 0.24V 16 FG zero-cross - 0.69V BUF_AMP + PHASE COMPENSATION
FG INPUT(+) 30 FG INPUT(-) 1
FG_AMP + -
FG OUTPUT 11 FG ZERO 10 CROSS Timing detector VOLTAGE REGULATOR INDEX BURST 4 2.2V 5 OSC RPM select Clock divider Speed control Burst time circuit
Pulse width adjustment
6
INDEX OUTPUT INDEX PULSE WIDTH CHARGE PUMP OUTPUT
3 Charge pump
13
OSC INPUT 14
12 RPM SELECT
9
8
23
15
21 NC
SIGNAL GROUND
4
FAN8422G
Absolute Maximum Rating (Ta=25C)
Parameter Maximum Power Supply Voltage Maximum Input Voltage Maximum Output Current Continuous Output Current Power Dissipation Operating Temperature Junction Temperture Storage Temperature Symbol VCCMAX VINMAX IOMAX IO PD TA TJ TSTG Value 7.0 0 ~ VCC 1 0.7 1.5 0 ~ 75 150 -55 ~ +125 Unit V V A A W C C C
Power Dissipation Curve
2.0 1.5 1.0 0.5 0
Power Dissipation : PD[W]
0
25
50
75
100
125
150
175
Ambient temperature, Ta [C]
Power dissipation decreases in the rate of 12mW / C when mounted on 76.2mm x 114.3mm x 1.6mm PCB (Phenolic resin material) and used above Ta=25C.
Recommended Operating Conditions (Ta=25C)
Parameter Supply Voltage Ambient Operating Temperature Range Symbol VCC Ta Min. 4.5 0 Typ. 5.0 Max 5.5 70 Unit V C
Temperature Characteristic
Parameter Thermal Shutdown Temperature
Note: Design reference value
Note
Symbol TSD
Min. 125
Typ. 150
Max -
Unit C
5
FAN8422G
Electrical Characteristics
(Ta=25C, VCC=5V, unless otherwise specified) Parameter SUPPLY CURRENT Supply Current 1 Supply Current 2 CHIP ENABLE INPUT Input Current Input Low Voltage Input High Voltage RPM SELECT INPUT Input Current Input Low Voltage Input High Voltage HALL AMP Input Resistance Note Common Mode Input Voltage Range Differential Input Voltage Range START-UP Hall Bias Voltage 1 Hall Bias Voltage 2 Reference Voltage Bias Off Current OUTPUT AMP Leakage Current Saturation Voltage 1 Saturation Voltage 2 BUFFER & CONTROL AMP Voltage Gain 1 Note Reference Voltage 1 Reference Voltage 2
Note: Design reference value
Note Note Note Note
Symbol
Conditions VCC=5.5V CE=H, RPM=L VCC=5.5V, CE=L CE=0~5V CE=0~5V IH=4mA, CE=L IH=10mA, CE=L IO=1mA, CE=L VH=5.5V, CE=H IO=0.35A IO=0.7A Current limiter voltage Control begin voltage
Min.
Typ.
Max.
Unit
ICCO ICC ICE VCEL VCEH IRPM VRPML VRPMH RIN VCOM VDIF VHB1 VHB2 Vref IHOFF ICER Vsat1 Vsat2 GCT1 Vref1 Vref2
3.5 3.5 1 2.0 140 2.3 2.7 1.7 -
1.0 15 5 5 10 2.5 2.9 2.2 5 0.5 1.0 1.3 -11 0.69
2.0 23 10 1.0 10 1.0 VCC 420 2.7 3.1 2.7 10 1 1.2 1.8 -
mA mA A V V A V V k V mVPP V V V A mA V V dB V V
0.205 0.208 0.210
6
FAN8422G
Electrical Characteristics (Continued)
(Ta=25C, VCC=5V, unless otherwise specified) Parameter CHARGE PUMP Charge Current Discharge Current Current Ratio Off Current Clamp Voltage FG AMP Output DC Voltage Note Voltage Gain 2 Input Voltage Range Noise Margin 1 Noise Margin 2
Note Note Note Note Note
Symbol ICP- ICP+ IR IOFF VCLP VFG GFG VIN ND NC N1 N2 FD IBI VTH1 VTH2 ICT2 VTH3 IOH VO1
Conditions RPM=L RPM=L ICP+ / ICP- VCP=0.63V Differential noise Common mode noise RPM=L RPM=H RPM=L RPM=H IO=1mA
Min. -15 15 0.9 1.0 24 2.0 1.2 1.05 -19 0.9 -
Typ. -20 20 1.0 1.3 1.3 34 1666.5 1388.5 1.0 1 1.45 1.3 -25 1.1 1 0.2
Max. -25 25 1.1 50 1.5 1.6 44 20 0.5 0.5 1.1 2 1.7 1.55 -36 1.3 2 0.4
Unit A A nA V V dB mVP-P mVP-P VP-P MHz A V V A V A V
SPEED CONTROL Count Range 1note Count Range 2 Operating Freq. BURST ADJUSTMENT Input Current Threshold Voltage 1 Threshold Voltage 2 PULSE WIDTH ADJUSMENT Ct2 Charge Current Threshold Voltage 3 INDEX OUTPUT Output Leakage Current Note Output Low Voltage
Note: Design reference value
Note
7
FAN8422G
Application Information
1. Chip Enable
This function turns on or off all blocks by low or high signal (active low).
2. U, V And W Phase Output Amp
These ampilifiers drive three phase outputs - U, V, and W which have 120 degree phase differences with each other. The three phase waveforms are made with the two hall sensor signals by synthesizing the third phase signal.
3. Speed Control Part
This function compares the real motor rotation frequency with the 300 or 360Hz pulse divided from 1MHz clock pulse for removing speed error when the motor is 'on' and speed error is detected by PLL. The speed error is sent to the charge pump, which repeats charging and discharging according to the error level. The charge pump output controls the output current to keep the rotational speed stable.
4. Sensorless Index Signal Generation
FAN8422G can make index signals without an index hall sensor by special rotor magnetization.
Typical Application Circuits
+5V SW1 DISK_IN W_P CURRENT DETECTION2 CURRENT DETECTION1 220nF 1 1
H_D SW2
100
100nF
VCC
LED
HU
U INPUT(+) U INPUT(-)
U PHASE OUTPUT U 25 24 22 16 1.8M 10k INDEX OUTPUT INDEX PULSE WIDTH 100nF V PHASE OUTPUT V W PHASE OUTPUT W PHASE COMPENSATION +5V
20 19 26 27 29 2 7 30 1 10 4
17
16 28
HV
V INPUT(+) V INPUT(-) HALL BIAS AGC
CE 47nF 47nF
CE FG_INPUT(+) FG_INPUT(-) FG ZERO CROSS
FAN8422G
6 3 13
CHARGE PUMP OUTPUT
10nF
100nF
56k VR
VOLTAGE REGULATOR INDEX BURST 47nF 5 14 12 OSC INPUT RPM SELECT
23 8 9 SIGNAL GROUND
330k
47k 1MHz RPM_SEL INDEX
8
FAN8422G
Mechanical Dimensions (Unit: mm)
Package Dimensions
30-SSOP-375
9
FAN8422G
DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.
www.fairchildsemi.com 5/6/03 0.0m 001 Stock#DSxxxxxxxx 2003 Fairchild Semiconductor Corporation
2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.

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