CXA3171N 4ch. Read/Write Amplifier for three terminal MIG Head of Hard Disk Drive For the availability of this product, please contact the sales office. Description The CXA3171N is a Read/Write Amplifier for the special three terminal MIG head of hard disk drive and designed to handle up to 4 channel heads. Features • Operate on single +5 V power supply • Low power consumption Read : 95 mW Write : 115 mW + IW × 5 • Designed for special three terminal MIG heads • Read amplifier emitter follower output featuring 420 times gain (typ). • Differential input capacitance for Read : 6.7 pF (typ) • Input noise : 0.46nV / √ Hz (typ) • Differential Head voltage swing : 9 Vp-p (typ) • Differential P-ECL write data input • Built-in write unsafe detection circuit. • Built-in Servo write function (2/4 ch). • Built-in IC protection circuit for short of head and GND. • Read data outputs are high impedance in write mode. • Built-in supply voltage monitor circuit prohibits incorrect write during power on or abnormal voltage. • Self switching damping resistance (RD=420 Ω). 24 pin SSOP (Plastic) Absolute Maximum Ratings (Ta=25 °C) • Supply voltage VCC 6 V • Write current IW 23 mAo-p • Operating temperature Topr –20 to +75 °C • Storage temperature Tstg –55 to +150 °C • Allowable power dissipation PD 800 mW • WUS/SE pin input current ISEH 15 mA Recommended Operating Conditions • Supply voltage VCC 5.0 V±10 % • Write current IW 10 to 22 mAo-p Function Read, Write and Write unsafe detection for HDD, power supply ON/OFF detection. Structure Bipolar silicon monolithic IC Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits. —1— E97305A7X-TE CXA3171N H0X 1 24 GND AMP MODE CONTROL H0C 2 H0Y 3 H1X 4 23 R/W DRIVER WRITE CURRENT SOURCE 22 WC 21 RDY AMP AMP H1C 5 H1Y 6 H2X 7 H2C 8 H2Y 9 H3X 10 20 RDX DRIVER 19 HS0 HEAD SELECT AMP 18 HS1 17 NC DRIVER 16 WDX 15 WDY AMP H3C 11 H3Y 12 DRIVER IC PROTECTOR —2— WRITE UNSAFE DETECTOR 14 WUS/SE POWER ON/OFF DETECTOR 13 VCC CXA3171N Pin Description No. Symbol 24 GND Description Equivalent circuit 1 1 2 3 4 5 6 7 8 9 10 11 12 H0X H0C H0Y H1X H1C H1Y H2X H2C H2Y H3X H3C H3Y VCC 4 7 10 2k 2k 2 Head. 4 channels provided. 5 8 11 3 6 9 GND 12 VCC 14 Write unsafe detection output / Servo Enable signal input. 14 WUS/SE GND VCC 15 16 WDY WDX 15 Differential P-ECL write data input. 16 GND 13 17 VCC NC 5 V power supply. —3— CXA3171N No. Symbol Description Equivalent circuit VCC 18 19 HS1 HS0 Head select signal input. Selects one of 4 heads according to Table 2. 18 19 R 2.1V GND HS0:R=78K, HS1:R=100K VCC Read/Write signal input At “High” : Read, at “Low” : Write. 180k 23 R/W 23 2.1V GND VCC 20 21 20 RDX RDY Read Amplifier output. 21 GND VCC 22 A setting resistor for the write current value is connected between this pin and GND. WC 22 2V GND —4— —5— 4 3-2 3-1 2-7 2-6 2-5 2-4 2-3 2-2 2-1 1-2 1-1 No. Supply power ON/OFF detector threshold voltage Current consumption for Read Current consumption for Write Digital input “Low” input voltage Digital input “High” input voltage Digital input “Low” input current Digital input “High” input current Write data input “Low” input voltage Write data input “High” input voltage Write data input current Write unsafe output saturation voltage Write unsafe output leak current Item Electrical Characteristics VTH IWUS VWUS IWD VWDH VWDL IIH IIL VIH VIL IWR IR Symbol b b b b b a a a a b a a b a a b a b b b b a a a a e b a a b a a b a b b b b b a a a b b a c c a a b a b b b b a a a a e b a a b a a a a a a a a a a a a e b a a b b b b b a a a a a a a a e b a a b a a b a b b b b a a a a e b a a b a a b a a a a a a a a a e b a a b a a b b SW conditions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 50 4.3 Test point : l3 When VCC is lowered from 5 V in Write mode and IW does not flow anymore, VCC voltage is set to VTHOFF. When VCC is raised from 3 V and IW starts to flow, VCC voltage is set to VTHON. 0.5 Output current : 1 mA Test point : V1 VWDH –0.25 VCC –0.4 100 50 3.4 VWDH –2.0 VCC –1.1 –100 3.9 +IW 2.0 +IW 23 17 +IW 0.8 36 19 12 28 V µA V µA V V µA µA V V mA mA Min. Typ. Max. Unit Input voltage : 4 V “High” applied voltage : 5 V “Low” applied voltage : 0 V Test point : l6, l7, l8, I9 Digital input : Pins 18, 19, 23 Test point : l2 Test point : l2 Measurement conditions (Unless otherwise specified, VCC=5 V, Ta=25 °C, Write current IW=20 mA) CXA3171N AW KW Write current voltage Write current gain Write current setting constant WUS/SE voltage WUS/SE sink current 5-2 5-3 5-4 6-1 6-2 —6— BW Frequency band width (–3 dB) Input referred noise 7 8 9 EN AV Read amplifier differential voltage gain ISEH VSEH VWC IW Write current setting range 5-1 Symbol Item No. a a a a a a a a e b a a b a a b b a a a a b a a a c b a a b a a b b a a a a b a a a c b a a b a a b b b b b b b a a a a b b a a a a b a b b b b b a a a a b b a a a a b a b b b b b a a a a b a a b a a b a b b b b a a a a e b a a b a a a a SW conditions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Input voltage SG1 : 1 mVp-p, 300 kHz Load resistance (RDX, RDY) : 1 kΩ Test point : V4 [Vp-p] V4 AV = SG1 Frequency at which AV lowers by 3 dB Head impedance : 0 Ω, when the read amplifier output voltage is amplified 100 times and voltage passed though a LPF (low pass filter of cutoff frequency 15 MHz) is VN [Vrms], VN EN = 100 • AV√ 15 × 106 Test point : V5 Servo write enabled Servo write enabled IW=KW/RWC IW=AW • VWC/RWC Measurement conditions 100 355 5 VCC +1.5 45 18 2.25 10 V mAo-p 485 14 VCC +1.6 55 nV √ Hz MHz V/V mA V 22 mA/mA 2.75 0.46 0.65 140 420 50 20 2.5 22 Min. Typ. Max. Unit CXA3171N —7— Channel separation Read data output offset voltage for Read 13 VOFFR CS PSRR Power supply rejection ratio 11 12 CMRR Symbol Common mode rejection ration Item 10 No. a a a a a a a a e b a a b a a a b a a a a a b a a c b a a b a a b b a a a a a a a a e a a a b a a b b a a a a b a a a d b a a b a a b b SW conditions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 In-phase input voltage SG2 : 100 mVp-p, 20 MHz When the Read amplifier output is VCM [mVp-p], 100 CMRR = 20 log VCM +20 log AV Test point : V4 Ripple voltage SG3 : 100 mVp-p, 20 MHz When the Read amplifier output is VP [mVp-p], 100 PSRR = 20 log VP +20 log AV Test point : V4 Selected head input voltage : 0 mVp-p Unselected head input voltage SG1 : 100 mVp-p, 20 MHz When the Read amplifier output is VCS [mVp-p], 100 CS = 20 log VCS +20 log AV Test point : V4 VOFFR = V2–V3 Test point : V2, V3 Measurement conditions –300 50 50 50 300 mV dB dB dB Min. Typ. Max. Unit CXA3171N Symbol Vdiff VRD Item RDX, RDY common mode output voltage difference between modes RDX, RDY common mode output voltage for Read No. 14 15 a a a a a a a a e b a a b a a a b a a a a a a a a e b a a b a a a c SW conditions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Test Point : V2, V3 Test point : Pin 20, 21 Measurement conditions 300 VCC VCC VCC –2.6 –2.3 –2.0 –300 V mV Min. Typ. Max. Unit CXA3171N —8— CXA3171N Unless otherwise specified, VCC=5 V, Ta=25 °C, fWD (Write data frequency) =5 MHz, IW=20 mA, LH (Head inductance) =1 µH, RH (Head DC resistance value) =12 Ω Refer to Fig. 2 to Fig. 4 No. 14 Item Head differential voltage amplitude Mode switching time 15-1 Read to Write Symbol Measurement conditions VSW Differential voltage between HX pin and HY pin at switching of Write current TRW TWR1 15-2 Mode switching time Write to Read TWR2 16-1 Mode switching time safe to unsafe TSA1 16-2 Mode switching time unsafe to safe TSA2 17 Head switching time TH 18 Write current propagation delay time TPD 19 Write current rise/fall time TR/TF Min. Typ. Max. Unit TRW is the time required for Write current to turn to 90 % after Pin 23 changes from “High” to “Low”. TWR1 is the time required for the Read amplifier output∗ to turn to 90 % after Pin 23 changes from “Low” to “High”. TWR2 is the time required for Write current to decreases to 10 % after Pin 23 changes from “Low” to “High”. TSA1 is the time required for Pin 14 to turn “High” after the last transition of Write data 1.0 when Write data is stopped in Write mode. TSA2 is the time required for Pin 14 to turn “Low” after the first transition of Write data in Write mode. TH is the time required for the Read amplifier output∗ to reach 90 % when the selected head switched in Read mode. TPD is the time required for Write current to reach 90 % after the Write data falling edge. LH=0 µH, RH=0 Ω TR is the time required for Write current to reach 90 % from 10 %; TF is the same time required to reach 10 % from 90 %. LH=0 µH, RH=0 Ω ∗Read amplifier output 100 mVp-p 10 MHz —9— 9 Vp-p 130 150 ns 180 220 ns 100 200 ns 2.3 3 µs 0.6 µs 0.6 µs 2 7 ns 1 3 ns CXA3171N Test Circuit 1 VCC 5V 1µ ×100 LPF to15MHz V A ×1 S10 AMP V 1µ V4 PG 1µ SG5 PG 5V a b V SG6 6V SG4 3V V2 a b a b a b S15 S16 A 2.7k I8 5.1k PG V V3 a b c S17 A I2 SG3 a b AMP V5 4V abc S14 A I7 S13 A I6 a b a bc I5 V S12 A I4 V1 S11 A I3 24 23 22 21 20 19 18 17 16 15 14 13 1 2 3 4 5 6 7 8 9 10 11 12 a b S1 a b a b S2 S5 a b VCC 5V a b S3 S6 a b a b a b S4 S7 a b a b S8 a b a b S9 a b c d e a b c A d e 0.1µ I1 Fig. 1 SG2 33 0.1µ 0.1µ SG1 Test Circuit 2 1k 1k ×1 1µ AMP 1µ PG 5V 1µ PG 2.7k PG PG 5.1k 24 23 22 21 20 19 18 17 16 15 14 13 1 2 3 4 5 6 7 8 9 10 11 12 LH 1µH LH 1µH LH —10— 1µH LH 1µH Fig. 2 CXA3171N Timing Chart 1 WDX WDY R/W 50% 50% TRW TWR 2 90% 90% IWX IWY 10% 10% TWR1 90% RDX RDY Fig. 3 Timing Chart 2 WDX WDY TPD IWX IWY 90% 90% 10% 10% TR WUS 90% TF 50% TSA1 50% TSA2 Fig. 4 —11— CXA3171N Description Functions Read amplifier This is a low noise amplifier for amplifying the signals from the heads with an emitter follower output. The RDX and RDY are the outputs of the differential amplifier whose polarity between the RDX and X side of the head input is same. Write circuit The Write data input to WDX pin and WDY pin passes through the buffer amp. It drives the Write switch circuit which supplies the Write current to the heads. The Write current flows into the X side when WDX is “Low” and WDY is “High”. Mode control The mode are set as shown Table 1 by R/W and WUS/SE. R/W WUS/SE HS0 HS1 L X See Table 2 H X L ∗∗ See Table 3 Table 1. Mode selection Mode Write Read Servo Write Head selection The heads are selected as shown in Table 2 by the HS0, HS1 and HS2 pins. HS0 HS1 Head L L 0 H L 1 L H 2 H H 3 Table 2. Head selection Servo write mode ∗∗ This mode allows for writing to multiple channels at once. To enable servo write mode follow these steps: (1) Place the device in the Read mode. (2) Set HS0 and HS1 following Table 3. (3) Set WUS/SE to VSEH, or input ISEH to WUS/SE. (4) While maintaing step (2) and (3) above make R/W low, placing the device in servo write mode. —12— CXA3171N Write unsafe detection circuit This circuit detects write errors. In normal Write mode, the WUS output is low; in the conditions listed below, it is high. • Head inputs is open (under the condition which. RH=∞ and Write data frequency is ≤ 10 MHz) • Head input is shorted to GND or VCC. • Write data frequency is abnormally low. • No write current. • In read mode. • Supply voltage is abnormal (see power supply ON/OFF detection). Power supply ON/OFF detection This circuit monitors VCC to detect erroneous Writes. The error status is established when VCC falls below the threshold voltage (VTH) of the power supply ON/OFF detector, in which case the recording and playback functions are prohibited. When VCC rises above VTH, the prohibition of these functions is released. HS0 HS1 Head L L 0, 1 H L 0, 1, 2, 3 L H 2, 3 H H 0, 1, 2, 3 Table 3. Head selection in Servo Write mode —13— CXA3171N Application Circuit +5V 1µ 1µ RWC 1µ 5.1k 2.7k 24 23 22 21 20 19 18 17 16 15 14 13 1 2 3 4 5 6 7 8 9 10 11 12 LH 1µH LH 1µH LH 1µH LH 1µH Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same. —14— CXA3171N Notes on operation • This device handles high frequency and high gain signals. Please note the following; ♦ Connect VCC decoupling capacitor of approximately 1000 pF near the device. ♦ Make the GND area as large as possible. • When using as 2-channel, short-circuit the X and Y sides of unused head pins or leave them open. • The WC pin is a constant voltage pin. When noise affects this pin, it creates noise in Write c current. Therefore, locate RWC as close to the device as possible. • Write unsafe detection circuit This circuit uses the voltage waveforms of the head pins for detection. Wave form of write data Voltage waveform of head pins (HX, HY) VFB VTH=1.4V VTH GND ♦ VFB must be more than 2 V. When VFB < 2 V, it is possible that Write unsafe detection maximum frequency becomes more than 1 MHz. ♦ The normal operating area of write unsafe detection circuit is changed by head inductance, head DC resistance, write current and other. —15— CXA3171N Application Notes Use the following characteristics for reference. VCC=5V, Ta=25 °C Item Symbol Differential output capacitance Differential output resistance Differential input capacitance Read mode Differential input resistance Output resistance Unselected head differential current in Write mode CO RO CI RI RRD Write current symmetry TAS∗ Write mode Conditions Between head input pins Between head input pins f=5 MHz RDX or RDY, f=5 MHz LH=1 µH, RH=12 Ω IW=20 mA LH=0 µH, RH=0 Ω IW=20 mA IUS Min. Typ. Max. Unit 4.5 6 300 420 545 6.7 10 520 1200 2400 50 pF Ω pF Ω Ω 0.2 mAp-p –0.5 ∗TAS=T1–T2 IWX+IWY 50% T1 50% 50% T2 WC Setting of Write current Write current can be set with resistor RWC (kΩ) at Pin 22. IW=K/RWC (mA) Refer to Fig. 5. IW -Write current (mA) Fig.5 Write current vs. RWC 20 10 5 2 5 10 RWC (kΩ) —16— 22 RWC 0.5 ns CXA3171N Normalized write current vs. Supply voltage Normalized write current vs. Ambient temperature Ta=25°C RWC=3.3kΩ 1.02 1 0.96 0.96 5 6 –25 0 25 75 50 Supply voltage VCC [V] Ambient temperature Ta [°C] Normalized read amplifier voltage tgain vs. Supply voltage Normalized read amplifier voltage gain vs. Ambient temperature Ta=25°C 1.02 1 0.98 VCC=5V 1.04 AV/AV (Ta=25°C) AV/AV (VCC=5V) 1 0.98 1.04 0.96 1.02 1 0.98 0.96 4 5 6 –25 Supply voltage VCC [V] 4.2 OFF → ON 4 ON →OFF 3.8 3.6 –25 0 25 50 0 25 50 Ambient temperature Ta [°C] Power supply ON/OFF detector threshold voltage vs. Ambient temperature Power supply ON/OFF Detector Threshold Voltage [V] 1.02 0.98 4 VCC=5V RWC=3.3kΩ 1.04 IW/IW (Ta=25°C) IW/IW (VCC=5V) 1.04 75 Ambient temperature Ta [°C] —17— 75 CXA3171N Package Outline Unit : mm 24PIN SSOP(PLASTIC) + 0.2 1.25 – 0.1 ∗7.8 ± 0.1 24 0.1 13 ∗5.6 ± 0.1 7.6 ± 0.2 A 1 + 0.1 0.22 – 0.05 12 + 0.05 0.15 – 0.02 0.13 M 0.65 0.5 ± 0.2 0.1 ± 0.1 0° to 10° NOTE: Dimensions “∗” does not include mold protrusion. DETAIL A PACKAGE STRUCTURE PACKAGE MATERIAL EPOXY RESIN SONY CODE SSOP-24P-L01 LEAD TREATMENT SOLDER/PALLADIUM PLATING EIAJ CODE SSOP024-P-0056 LEAD MATERIAL 42/COPPER ALLOY PACKAGE MASS 0.1g JEDEC CODE NOTE : PALLADIUM PLATING This product uses S-PdPPF (Sony Spec.-Palladium Pre-Plated Lead Frame). —18—