19-1170; Rev 0; 12/96
KIT
ATION
EVALU
BLE
AVAILA
8-Bit, 750Msps Flash ADC
____________________________Features
o
o
o
o
o
1:2 Demuxed ECL-Compatible Outputs
Wide Input Bandwidth: 900MHz
Low Input Capacitance: 15pF
Metastable Errors Reduced to 1LSB
Single -5.2V Supply
_______________General Description
The MAX1151 is a parallel flash analog-to-digital con-
verter (ADC) capable of digitizing full-scale (0V to -2V)
inputs into 8-bit digital words at an update rate of
750Msps. The ECL-compatible outputs are demuxed
into two separate output banks, each with differential
data-ready outputs to ease the task of data capture.
The MAX1151’s wide input bandwidth and low capaci-
tance eliminate the need for external track/hold amplifi-
ers for most applications. A proprietary decoding
scheme reduces metastable errors to 1LSB. This device
operates from a single -5.2V supply, with a nominal
power dissipation of 5.5W.
MAX1151
________________________Applications
Digital Oscilloscopes
Data Acquisition
Transient-Capture Applications
Radar, EW, ECM
Direct RF/IF Downconversion
Pin Configuration appears on last page.
______________Ordering Information
PART
MAX1151AIZS
MAX1151BIZS
TEMP. RANGE
-20°C to +85°C
-20°C to +85°C
PIN-PACKAGE
80 MQUAD
80 MQUAD
_________________________________________________________Functional Diagram
CLK
NCLK
CLOCK
BUFFER
ANALOG
VRT INPUT
PREAMP COMPARATOR
255
DEMUX
CLOCK BUFFER
MAX1151
254
D8
(OVR)
D8B
D7B
•
•
D5B
•
•
ECL OUTPUT BUFFERS AND LATCHES
D2B
D1B
D0B
D8A
D7A
•
•
•
D5A
NDRB (NOT DATA READY)
DRB (DATA READY)
D8B (OVR)
D7B (MSB)
D6B
D5B
D4B
D3B
D2B
D1B
D0B (LSB)
NDRA (NOT DATA READY)
DRA (DATA READY)
D8A (OVR)
D7A (MSB)
D6A
D5A
D4A
D3A
D2A
D1A
D0A (LSB)
BANK A
BANK B
152
D7
(MSB)
256-BIT TO 8-BIT DECODER
WITH METASTABLE ERROR CORRECTION
D6
151
128
VRM
127
D5
D4
64
D3
63
1:2 DEMULTIPLEXER
D2
•
•
•
D2A
2
D1
D1A
1
D0
(LSB)
D0A
VFB
________________________________________________________________
Maxim Integrated Products
1
For the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
8-Bit, 750Msps Flash ADC
MAX1151
ABSOLUTE MAXIMUM RATINGS
Supply Voltages
Negative Supply Voltage (V
EE
to GND) .............-7.0V to +0.5V
Ground Voltage Differential .................................-0.5V to +0.5V
Input Voltages
Analog Input Voltage .............................................+0.5V to V
EE
Reference Input Voltage ........................................+0.5V to V
EE
Digital Input Voltage ..............................................+0.5V to V
EE
Reference Current (V
RT
to V
RB
)........................................35mA
Digital Output Current ...........................................0mA to -28mA
Operating Temperature Range ...........................-20°C to +85°C
Case Temperature ...........................................................+125°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10sec). ............................+300°C
Storage Temperature Range .............................-65°C to +150°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
EE
= -5.2V, V
RB
= -2.00V, V
RM
= -1.00V, V
RT
= 0.00V, f
CLK
= 750MHz, duty cycle = 50%, typical thermal impedance (θ
JC
) = 4°C/W,
T
j
= T
C
= T
A
= +25°C.) (Note 1)
PARAMETER
Resolution
DC ACCURACY
Integral Nonlinearity
Differential Nonlinearity
No Missing Codes
ANALOG INPUT
Input Voltage Range
Input Bias Current
Input Resistance
Input Capacitance
Input Bandwidth
Offset Error V
RT
Offset Error V
RB
Input Slew Rate
REFERENCE INPUT
Ladder Resistance
Reference Bandwidth
TIMING CHARACTERISTICS
Maximum Sample Rate
Aperture Jitter
Acquisition Time
CLK to DATA READY Delay
Clock to Data Delay
I
V
V
IV
IV
0.9
1.25
750
2
250
1.4
1.75
1.9
2.25
0.9
1.25
750
2
250
1.4
1.75
1.9
2.25
MHz
ps
ps
ns
ns
I
V
60
80
30
60
80
30
Ω
MHz
Over full input range
Small signal
Large signal
V
IN
= 0V
I
I
V
V
V
V
IV
IV
V
-30
-30
5
V
RB
0.75
15
15
900
500
30
30
-30
-30
5
V
RT
2.0
V
RB
0.75
15
15
900
500
30
30
V
RT
2.0
V
mA
kΩ
pF
MHz
mV
mV
V/ns
f
CLK
= 100kHz
f
CLK
= 100kHz
I
I
-1.0
-0.85
Guaranteed
1.0
0.95
-1.5
-0.95
Guaranteed
1.5
1.5
LSB
LSB
CONDITIONS
TEST
LEVEL
MIN
MAX1151A
TYP
MAX
8
MIN
MAX1151B
TYP
MAX
8
UNITS
Bits
2
_______________________________________________________________________________________
8-Bit, 750Msps Flash ADC
MAX1151
ELECTRICAL CHARACTERISTICS (continued)
(V
EE
= -5.2V, V
RB
= -2.00V, V
RM
= -1.00V, V
RT
= 0.00V, f
CLK
= 750MHz, duty cycle = 50%, typical thermal impedance (θ
JC
) = 4°C/W,
T
j
= T
C
= T
A
= +25°C.) (Note 1)
PARAMETER
DYNAMIC PERFORMANCE
Signal-to-Noise Ratio
(without harmonics)
Total Harmonic Distortion
Signal-to-Noise and
Distortion
Spurious-Free Dynamic
Range
DIGITAL INPUTS
Input High Voltage
(CLK, NCLK)
Input Low Voltage
(CLK, NCLK)
Clock Pulse Width High
(t
PWH
)
Clock Pulse Width Low
(t
PWL
)
Clock Synchronous
Input Currents
DIGITAL OUTPUTS
Logic "1" Voltage
Logic "0" Voltage
POWER-SUPPLY REQUIREMENTS
Supply Voltage (V
EE
)
Supply Current (I
EE
)
Power Dissipation
I
I
V
IV
I
I
-4.95
-1.1
-0.9
-1.8
2.4
-5.2
1.05
5.5
-5.45
1.2
6.25
-4.95
-1.5
-1.1
-0.9
-1.8
2.4
-5.2
1.05
5.5
-5.45
1.2
6.25
V
A
W
-1.5
V
V
I
I
I
I
V
0.67
0.67
-1.1
-0.7
-1.8
0.5
0.5
2
-1.5
0.67
0.67
-1.1
-0.7
-1.8
0.5
0.5
2
-1.5
V
V
ns
ns
µA
f
IN
= 50MHz
f
IN
= 250MHz
f
IN
= 50MHz
f
IN
= 250MHz
f
IN
= 50MHz
f
IN
= 250MHz
f
IN
= 50MHz
f
IN
= 250MHz
I
I
I
I
I
I
I
I
46
44
-45
-37
43
36
48
40
44
42
-43
-35
41
34
44
36
dB
dBc
dB
dB
CONDITIONS
TEST
LEVEL
MIN
MAX1151A
TYP
MAX
MIN
MAX1151B
TYP
MAX
UNITS
Note 1:
All parameters having min/max specifications are guaranteed. The Test Level column indicates the specific device testing actually
performed during production and Quality Assurance inspection. Unless otherwise noted, all tests are pulsed tests; therefore,
T
j
= T
C
= T
A
.
TEST LEVEL
I
II
III
IV
V
VI
TEST PROCEDURE
100% production tested at the specified temperature.
100% production tested at T
A
= +25°C, and sample tested at the specified temperatures.
QA sample tested only at the specified temperatures.
Parameter is guaranteed (but not tested) by design and characterization data.
Parameter is a typical value for information purposes only.
100% production tested at T
A
= +25°C. Parameter is guaranteed over specified temperature range.
_______________________________________________________________________________________
3
8-Bit, 750Msps Flash ADC
MAX1151
______________________________________________________________Pin Description
PIN
1, 2, 3
4, 5, 19, 20, 22, 23, 27, 28, 38, 39,
40, 46, 47, 49, 60, 67, 79
6
7, 9, 11, 54, 56, 58,
69, 71, 73, 75, 77
8
10
12
13, 14, 31, 34, 41, 63, 64
15-18, 25, 26, 29, 30, 36,
37, 44, 45, 51, 52
21
24
32, 33
35
42
43
48
50
53
55
57
59, 61, 62, 65, 66, 68
70
72
74
76
78
80
NAME
D2B, D3B, D4B
V
EE
D5B
DGND
D6B
D7B
D8B
N.C.
AGND
VRBF
VRBS
VIN
VRM
VRTF
VRTS
NCLK
CLK
DRA
NDRA
D0A
D1A–D6A
D7A
D8A
NDRB
DRB
D0B
D1B
FUNCTION
Data Output Bank, Bits 2, 3, and 4
Negative Supply, nominally -5.2V
Data Output Bank B, Bit 5
Digital Ground
Data Output Bank B, Bit 6
Data Output Bank B, Bit 7 (MSB)
Data Output Bank B, Bit 8 (OVR)
No Connection. Not internally connected.
Analog Ground
Reference-Voltage Force Bottom
Reference-Voltage Sense Bottom
Analog Input Voltage. Can be either voltage or sense.
Reference-Voltage Middle, nominally -1V
Reference-Voltage Force Top
Reference-Voltage Sense Top
Inverse Clock Input
Clock Input
Data Ready Bank A
Not Data Ready Bank A
Data Output Bank A, Bit 0 (LSB)
Data Output Bank A, Bits 1–6
Data Output Bank A, Bit 7 (MSB)
Data Output Bank A, Bit 8 (OVR)
Not Data Ready Bank B
Data Ready Bank B
Data Output Bank B, Bit 0 (LSB)
Data Output Bank B, Bit 1
_______________Detailed Description
The MAX1151 is one of the fastest monolithic, 8-bit, paral-
lel, flash analog-to-digital converters (ADCs) available
today. The nominal conversion rate is 750Msps, and the
analog bandwidth is in excess of 900MHz. A major
advance over previous flash converters is the inclusion of
255 input preamplifiers between the reference ladder and
input comparators (see
Functional Diagram).
This not
only reduces clock transient kickback to the input and
reference ladder but also reduces the effect of the input
signal’s dynamic state on the input comparators’ latching
characteristics. The preamplifiers act as buffers to stabi-
lize the input capacitance so that it remains constant over
different input voltage and frequency ranges, making the
part easier to drive than previous flash converters. The
preamplifiers also add a gain of +2 to the input signal, so
that each comparator has a wider overdrive or threshold
range to trip into or out of the active state. This gain
reduces metastable states that can cause errors at the
output.
4
_______________________________________________________________________________________
8-Bit, 750Msps Flash ADC
The MAX1151 has true differential analog and digital
data paths from the preamplifiers to the output buffers
(current-mode logic) for reducing potential missing
codes while rejecting common-mode noise.
Signature errors are also reduced by careful layout of the
analog circuitry. The device’s output drive capability can
provide full ECL swings into 50Ω loads.
Table 1. Output Coding
V
IN
(V)
0
D8
1
D7 . . . D0
10000000
10000001
10000011
•
•
•
10100001
10100000
11100000
•
•
•
11000001
11000000
01000000
•
•
•
01100001
01100000
00100000
•
•
•
00000011
00000001
00000000
MAX1151
Typical Interface Circuit
The circuit of Figure 1 shows a method of achieving the
least error by correcting for integral linearity, input-
induced distortion, and power-supply/ground noise. This
is achieved with the use of external reference-ladder tap
connections, an input buffer, and supply decoupling.
Contact the factory for the MAX1150/MAX1151 evalua-
tion kit manual, which contains more details on interfac-
ing the MAX1151. The function of each pin and external
connections to other components are described in the fol-
lowing sections.
-0.5
0
-1.0
0
-1.5
0
VEE, AGND, DGND
V
EE
is the supply pin with AGND as ground for the
device. The power-supply pins should be bypassed as
close to the device as possible with at least a 0.01µF
ceramic capacitor. A 1µF tantalum can also be used for
low-frequency suppression. DGND is the ground for the
ECL outputs, and should be referenced to the output
pulldown voltage and appropriately bypassed, as shown
in Figure 1.
VIN (Analog Input)
There are two analog input pins that are tied to the same
point internally. Either one may be used as an analog
input sense, while the other is used for input force. This is
convenient for testing the source signal to see if there is
sufficient drive capability. The pins can also be tied to-
gether and driven by the same source. The MAX1151 is
superior to similar devices due to a preamplifier stage
before the comparators. This makes the device easier to
drive because it has constant capacitance and induces
less slew-rate distortion.
CLK, NCLK (Clock Inputs)
The clock inputs are designed to be driven differentially
with ECL levels. The duty cycle of the clock should be
kept at 50%, to avoid causing larger second harmonics.
If this is not important to the intended application, duty
cycles other than 50% may be used.
D0 to D8, DR, NDR (A and B)
The digital outputs can drive 50Ω to ECL levels when
pulled down to -2V. When pulled down to -5.2V, the out-
puts can drive 130Ω to 1kΩ loads. All digital outputs are
gray code, with the coding as shown in Table 1.
-2.0
0
VRBF, VRBS, VRTF, VRTS, VRM
(Reference Inputs)
There are two reference inputs and one external refer-
ence voltage tap. These are -2V (VRB force and sense),
mid-tap (VRM), and AGND (VRT force and sense). The
reference pins and tap can be driven by op amps (as
shown in Figure 1), or VRM can be bypassed for limited
temperature operation. These voltage inputs can be by-
passed to AGND for further noise suppression, if
desired.
Thermal Management
The typical thermal impedance (θ
CA
) for the MQUAD
package has been measured at
θ
CA
= 17°C/W, in still
air with no heatsink.
To ensure rated performance, we highly recommend
using this device with a heatsink that can provide ade-
quate air flow. We have found that a Thermalloy 17846
heatsink with a minimum air flow of 1 meter/second
(200 linear feet per minute) provides adequate thermal
performance under laboratory tests. Application-specif-
ic conditions should be taken into account to ensure
that the device is properly heat sinked.
_______________________________________________________________________________________
5
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