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19-1335; Rev 0a; 2/98
MAX1011 Evaluation Kit
General Description
The MAX1011 evaluation kit (EV kit) simplifies evaluation
of the 90Msps MAX1011 6-bit analog-to-digital converter
(ADC). The kit includes the basic components necessary
to operate the on-chip oscillator as a voltage-controlled
oscillator (VCO). The board can also be easily modified to
accommodate an external clocking source.
Connectors for power supplies, analog inputs, and digital
outputs simplify connections to the device. The PC board
features an optimized layout to ensure the best possible
dynamic performance. The EV kit includes a MAX1011.
Features
o
5.85 Effective Number of Bits at 20MHz Analog
Input Frequency
o
Separate Analog and Digital Power and Ground
Connections with Optimized PC Board Layout
o
Single-Ended or Differential Analog Input
o
Square-Pin Header for Easy Connection of Logic
Analyzer to Digital Outputs
o
User-Selectable ADC Full-Scale Gain Ranges
o
Fully Assembled and Tested Surface-Mount
Board
Evaluates: MAX1011
Component List
DESIGNATION QTY
C1, C3,
C5
C2, C7,
C8
C4
C6
C9, C10
C11, C12
D1
J1
JU1, JU2, JU6
JU3, JU4
JU5
L1
R1
R2, R3
R4, R5
U1
IN+, IN-
Clock
Overdrive
None
None
3
3
1
1
2
2
1
1
3
2
1
1
1
2
2
1
2
0
1
1
DESCRIPTION
0.01µF, 10V min, 10% ceramic
capacitors
47pF, 10V min, 5% ceramic capacitors
0.22µF, 10V min, 10% ceramic
capacitor
5pF, 10V min, 10% ceramic capacitor
0.1µF, 10V min, 10% ceramic
capacitors
10µF, 10V min, 20% tantalum caps
AVX TAJC106K016
Varactor diode
M/A-COM MA4ST079CK-287, SOT23
14-pin connector
0Ω resistors
2-pin headers
3-pin header
220nH inductor
Coilcraft 1008CS-221XKB
10kΩ, 5% resistor
47kΩ, 5% resistors
49.9Ω, 1% resistors
MAX1011CEG
BNC connectors
Not Supplied
MAX1011 circuit board
Shunt for JU5
Ordering Information
PART
MAX1011EVKIT
TEMP. RANGE
0°C to +70°C
IC PACKAGE
24 QSOP
Component Suppliers
SUPPLIER*
AVX
Coilcraft
M/A-COM
Sprague
PHONE
(803) 946-0690
(847) 639-6400
(617) 564-3100
(603) 224-1961
FAX
(803) 626-3123
(847) 639-1469
(617) 564-3050
(603) 224-1430
*
Please indicate that you are using the MAX1011 when con-
tacting these component suppliers.
Quick Start
The MAX1011 EV kit is fully assembled and tested.
Follow these steps to verify proper board operation.
Do
not turn on the power supplies until all connections
to the EV kit are completed.
1) Connect a +5V power supply to the pad marked
VCC. Connect this supply’s ground to the pad
marked GND.
2) Connect a +3.3V power supply to the pad labeled
VCCO. Connect the supply ground to the pad
marked OGND.
3) Connect a +3.7V power supply to the pad marked
VTUNE. Connect the supply ground to the GND
pad.
4) Remove the shunt from jumper JU5. This sets a
250mVp-p full-scale range.
1
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
For small orders, phone 408-737-7600 ext. 3468.
MAX1011 Evaluation Kit
Evaluates: MAX1011
5) Connect a 250mVp-p, 20MHz sine-wave source to
the analog input at BNC J3. The analog input is ter-
minated in 50Ω (R4).
6) Connect a logic analyzer to connector J1 to monitor
the digital outputs.
7) Turn on all power supplies and signal sources.
8) Observe the digitized analog input signals with the
logic analyzer.
Table 2. Gain-Selection Jumper JU5
Settings
JU5 SETTING
JU5
1
2
3
MAX1011 GAIN
CONTROL PIN
GND
ADC GAIN RANGE
Low-gain, 500mVp-p
_______________Detailed Description
EV Kit Jumpers
The MAX1011 EV kit contains several jumpers that con-
trol board and part options. The following sections
describe the different jumpers and their purposes.
Table 1 lists the jumpers on the EV kit and their default
positions.
JU5
1
2
3
OPEN
Mid-gain, 250mVp-p
JU5
1
2
3
V
CC
High-gain, 125mVp-p
Table 1. EV Kit Jumpers and Default
Positions
JUMPER(S)
JU1, JU2,
JU6
JU3, JU4
JU5
FUNCTION
Power-supply current-
sense ports
Offset-correction
amplifier enabled
ADC full-scale range
selection
DEFAULT
POSITION
Shorted with 0Ω
resistors
Open
Open
Table 3. Typical Input-Drive Requirements
for Mid-Gain
INPUT DRIVE
Single-Ended
Noninverting
IN+
+125mV
0
-125mV
Open Circuit
Single-Ended
Inverting
Open Circuit
Open Circuit
+62.5mV
Differential
0
-62.5mV
IN-
Open Circuit
Open Circuit
Open Circuit
+125mV
0
-125mV
-62.5mV
0
+62.5mV
OUTPUT
CODE
111111
100000
000000
000000
011111
111111
111111
100000
000000
Analog Supply Power Requirements
The MAX1011 requires a +5V at approximately 37mA for
the analog V
CC
supply. 0Ω resistors are installed at
jumper sites JU1, JU2, and JU6 and can be removed to
sense device power-supply currents with an ammeter.
Digital Outputs Supply
The MAX1011 requires +3.3V for the V
CCO
supply. The
current requirement from the power supply is a function
of the sampling clock and analog input frequencies, as
well as the capacitive loading on the digital outputs.
With 15pF loads and a 20MHz analog input frequency
sampled at 90Msps, the current draw is approximately
8.5mA.
log inputs, plus the 0.1µF AC-coupling capacitor value,
sets the low-frequency corner at approximately 80Hz.
You can drive the analog inputs either single-ended or
differentially using AC- or DC-coupled inputs. Either the
inverting or the noninverting input can be driven single-
ended. If the inverting input is driven, then the digital
output codes are inverted (complemented). Refer to the
MAX1011 data sheet for typical circuits.
ADC Gain Selection
The single GAIN-select pin on the MAX1011 controls
the full-scale input range. Jumper JU5 is used to manu-
ally select the desired gain range as shown in Table 2.
The EV kits are shipped with the mid-gain range select-
ed (jumper pins open).
Table 3 lists the possible input-drive combinations
for the mid-gain (250mVp-p) full-scale range selection.
Drive levels are referenced to the open-circuit,
common-mode voltage of the analog inputs (typically
Analog Inputs
The analog inputs to the ADC are provided through
BNC connectors IN+, and IN-. The connectors are ter-
minated with 49.9Ω to ground and are AC coupled to
the converter’s analog inputs, which are internally self-
biased at 2.35V DC. A typical application circuit drives
the IN+ noninverting analog input using AC-coupled
signals. The nominal 20kΩ input resistance of the ana-
2
_______________________________________________________________________________________
MAX1011 Evaluation Kit
MAX1011 Fig01
110
105
100
FREQUENCY (MHz)
95
90
85
80
75
70
65
60
0
1
2
3
4
5
6
7
8
VTUNE CONTROL VOLTAGE (V)
Table 4. External Clock Source EV Kit
Modifications
COMPONENT
Clock Overdrive
(J2)
C6
C7, C8
L1
R1
R2, R3
D1
DESCRIPTION
Clock input BNC
connector
5pF capacitor
47pF capacitors
220nH inductor
10kΩ resistor
47kΩ resistors
Varactor diode
MODIFICATION
Add
Remove
Replace with
0.01µF capaci-
tors
Remove
Remove
Replace with
49.9Ω resistors
Remove
Evaluates: MAX1011
Figure 1. MAX1011 Oscillator Frequency vs. VTUNE Control
Voltage
2.35V) if DC coupled, or to ground if AC coupling is
used. If the low-gain (500mVp-p) range is selected, the
input-drive requirements are twice those listed in Table
3. If the high-gain (125mVp-p) range is selected, the
input-drive requirements are half those listed in Table 3.
External Clock Operation
The MAX1011 EV kit can be converted to drive the ADC
from an external clock source. This involves removing
the external resonator components from the VCO circuit
and adding a few new components. Table 4 lists the EV
kit changes required to convert the board to accept an
external clock source. The resulting schematic is
shown in Figure 3.
The new 49.9Ω value of R3 shown in Figure 3 provides
proper termination for a 50Ω external signal generator.
AC-coupling capacitor C7 couples the external clock
signal to the MAX1011 oscillator circuitry at TNK+ (pin
7). R2 and C8 ensure that the impedance at both ports
of the oscillator is balanced. After all modifications are
complete, connect an external clock source to the BNC
connector on the EV kit marked CLOCK OVERDRIVE
(J2). The recommended clock amplitude is 1Vp-p; how-
ever, the ADC operates correctly with as little as
300mVp-p or up to 1.25Vp-p on CLOCK OVERDRIVE.
The external clock source should have low-phase noise
for best dynamic performance. A low-phase-noise
sine-wave oscillator serves this purpose well. A square-
wave clock source is not necessary to drive the
MAX1011. The device contains sufficient gain to ampli-
fy even a low-level-input sine wave to drive the ADC
comparators, while ensuring excellent dynamic perfor-
mance.
Offset-Correction Amplifier
The offset-correction amplifier included on the
MAX1011 is usually enabled in a typical AC-coupled
application circuit. For DC-coupled applications, the
amplifier must be disabled by installing shorting blocks
on jumpers JU3 and JU4. These jumpers short device
pins OCC+ (pin 2) and OCC- (pin 3) to ground and dis-
able the amplifier. The MAX1011 EV kit is configured
with the offset-correction amplifier enabled (jumpers
open) and AC-coupled analog inputs.
Voltage-Controlled-Oscillator Operation
The EV kit includes a voltage-controlled-oscillator
(VCO) circuit to set the analog-to-digital converter
(ADC) sampling rate using an external resonant tank
and a varactor diode. A voltage applied to the VTUNE
pad changes the varactor diode’s capacitance to
adjust the tank’s resonant frequency, which sets the
oscillator’s sampling frequency. VTUNE voltage can be
varied from 0V to a maximum of 8V.
The EV kit is designed so that a nominal VTUNE control
voltage of about 3.7V sets the ADC sampling rate to
90Msps. The VTUNE control voltage should be well fil-
tered, as any noise on the supply contributes to jitter in
the internal oscillator and degrades the converter’s
dynamic performance. Figure 1 shows the VTUNE
control-voltage typical frequency-adjustment range for
the MAX1011 EV kit (for VCO mode, refer to schematic
in Figure 2).
_______________________________________________________________________________________
3
Evaluates: MAX1011
MAX1011 Evaluation Kit
Figure 2. MAX1011 EV Kit Schematic (Voltage-Controlled-Oscillator Mode)
C9
0.1µF
1
JU5
V
CC
2
3
R4
49.9Ω
(1%)
4
U1
MAX1011
1
GAIN
D5
D4
D3
D2
D1
DO
DCLK
V
CCO
OGND
GND
V
CC
GND
N.C.
V
CC
GND
JU6
0Ω
V
CC
VTUNE
JU1
VCC
C11
0Ω
10µF (10V)
GND
CUT HERE
TO SEPARATE
GROUNDS
C12
10µF (10V)
VCCO
VCCO
VCC
VTUNE
J1–2
J1–4
J1–6
J1–8
J1–10
J1–12
J1–14
17
16
15
14
13
C1
0.01µF
V
CC
18
19
20
21
22
23
OCC+
OCC-
IN+
IN-
V
CC
TNK+
TNK-
GND
24
JU4
2
3
4
C7
47pF
L1
220nH
6
7
C6
5pF
8
9
C8
47pF
11
12
C5
0.01µF
C3
0.01µF
10
5
1
C4
JU3 0.22
µF
J1–1
J1–3
J1–5
J1–7
J1–9
J1–11
J1–13
C2
47pF
GND PLANE RELIEVED UNDER THESE COMPONENTS
C10
0.1µF
R5
49.9Ω
(1%)
2
0Ω
JU2
OGND
IN+
J3
BNC
IN-
J4
BNC
TANK
R3
47k
D1
VTUNE
R1
10k
3
R2
47k
GND PLANE RELIEVED UNDER THESE COMPONENTS
_______________________________________________________________________________________
= ANALOG GROUND (GND)
= DIGITAL GROUND (OGND)
IN+
J3
C9
0.1µF
BNC
2
3
V
CC
1
JU5
IN-
J4
R4
49.9Ω (1%)
BNC
C10
0.1µF
U1
MAX1011
1
GAIN
D5
D4
D3
D2
D1
DO
DCLK
18
JU2
V
CCO
OGND
N.C.
V
CC
GND
JU6
0Ω
17
16
15
14
13
C1
0.01µF
V
CC
VCCO
C2
47pF
0Ω
19
20
21
22
23
OCC+
OCC-
IN+
IN-
V
CC
TNK+
TNK-
GND
GND
V
CC
GND
24
J1–1
J1–3
J1–5
J1–7
J1–9
J1–11
J1–13
GND PLANE RELIEVED UNDER THESE COMPONENTS
J2
JU4
2
C4
0.22µF
3
4
49.9Ω
(1%)
C7
0.01µF
5
6
7
C8
0.01µF
8
9
R2
10
C3
0.01µF
12
C5
0.01µF
11
JU3
R5
49.9Ω (1%)
CLOCK
BNC
OVERDRIVE
R3
Figure 3. MAX1011 EV Kit Schematic (External Clock Operation)
J1–2
J1–4
J1–6
JU1
VCC
C11
0Ω
10µF (10V)
GND
CUT HERE
TO SEPARATE
GROUNDS
C12
10µF (10V)
VCCO
VCCO
VCC
J1–8
J1–10
J1–12
J1–14
V
CC
VTUNE
VTUNE
OGND
49.9Ω
(1%)
= ANALOG GROUND (GND)
Evaluates: MAX1011
_______________________________________________________________________________________
= DIGITAL GROUND (OGND)
MAX1011 Evaluation Kit
5

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