The NTE3470 is a monolithic READ Amplifier System for obtaining digital information from floppy disk
storage. It is designed to accept the differential AC signal produced by the magnetic head and produce a digital output pulse that corresponds to each peak of the input signal. The gain stage amplifies
the input waveform and applies it to an external filter network, enabling the active differentiator and
time domain filter to produce the desired output.
Features:
DCombines All the Active Circuitry to Perform the Floppy Disk Read Amplifier Function in One Circuit
DImproved (Positive) Gain TC and Tolerance
DImproved Input Common Mode
Absolute Maximum Ratings: (TA = +25°C, Note 1 unless otherwise specified)
Power Supply Voltage (Pin11), V
Power Supply Voltage (Pin18), V
Input Voltage (Pin1 and Pin2), V
Output Voltage (Pin10), V
O
CC1
CC2
I
Operating Ambient Temperature Range, T
Operating Junction Temperature, T
Storage Temperature Range, T
Note 1. “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot
be guaranteed. They are not meant to imply that the device should be operated at these limits. The table of “Electrical Characteristics” provides conditions for actual device operation.
Differential Voltage GainA
Input Base CurrentI
Input Common Mode Range,
v
f = 200kHz, ViD = 7mV
VD
IB
5% Max THD–0.1–1.5V
iCM
Linear Operation
Differential Input Voltage, Linear Op-
v
5% Max THD––25mV
iD
eration
Output Voltage Swing Differentialv
Output Source Current, ToggledI
Output Sink Current (Pin16 and Pin17)I
Small Signal Input Resistancer
Small Signal Output Resistance,
Single Ended
Bandwidth, –3dBBWviD = 2mV
oD
O
OS
TA = +25°C100250–kΩ
i
r
TA = +25°C, V
o
V
V
CC2
CC1
= 12V
RMS, TA
= 5V, V
CC1
CC2
= 5V,
= +25°C,
= 12V
Common Mode Rejection RatioCMRRTA = +25°C, f = 100kHz,
AVD = 40dB, vin = 200mV
V
CC1
V
Supply Rejection RatioTA = +25°C, V
CC1
4.75V ≤ V
V
Supply Rejection RatioTA = +25°C, V
CC2
10V ≤ V
Differential Output OffsetV
Common Mode Output OffsetV
TA = +25°C, viD = vin = 0V––0.4V
DO
viD = vin = 0V, Differential and
CO
= 5V, V
CC1
CC2
= 12V
CC2
= 12V,
CC2
≤ 5.25V, AVD = 40dB
= 5V,
CC1
≤ 14V, AVD = 40dB
Common Mode
RMS
P–P
80100130V/V
––10–25µA
P–P
34–V
P–P
–8.0–mA
2.84.0–mA
–15–Ω
10––MHz
50––dB
,
50––dB
50––dB
–3.0–V
Differential Noise Voltage Referred
e
TA = +25°C, BW = 10Hz to 1MHz–15–µV
n
to Input
Supply CurrentI
CC
V
= 5.25V, S1 to Pin12 or Pin13–40–mA
CC1
V
= 14V–4.8–mA
CC2
Active Differentiator Section
Differentiator Output Sink Current,
I
OD
VOD = V
CC1
1.01.4–mA
Pin12 and Pin13
Peak ShiftPSNote 2––5%
Differentiator Input Resistance,
r
iD
–30–kΩ
Differential
Differentiator Output Resistance,
r
TA = +25°C–40–Ω
oD
Differential
Note 2. f = 250kHz, viD = 1V
t
CC2
PS1
t
PS1
= 12V
where PS = 1/2x 100%
V
= 5V, V
CC1
P–P
– t
+ t
, i
PS2
PS2
cap
= 500µA
RMS
Page 3
Electrical Characteristics (Cont’d): (TA = 0° to +70°C, V
unless otherwise specified)
ParameterSymbolTest ConditionsMinTypMaxUnit
Digital Section
= 4.75 to 5.25V, V
CC1
= 10 to 14V
CC2
Output Voltage High Logic Level, Pin10V
Output Voltage Low Logic Level, Pin10V
Output Rise Time, Pin10t
Output Fall Time, Pin10t
Timing Range Mono #1 (t1A and t1B)t1A, t
Timing Accuracy Mono #1E
Timing Range Mono #2t2150–1000ns
Timing Accuracy Mono #2E
Note 3. R1 = 6.4kΩ, C1 = 200pF.
Note 4. Accuracy guaranteed for R1 in the range 1.5kΩ ≤ R1 ≤ 10kΩ and C1 in the range 150pF ≤
C1 ≤ 680pF.
Note 5. To minimize current transients, C1 should be kept as small as is convenient.
Note 6. R2 = 1.6kΩ, C2 = 200pF.
Note 7. Accuracy guaranteed for R2 in the range 1.5kΩ ≤ R2 ≤ 10kΩ and C2 in the range 100pF ≤