Analog Devices SCP-LT8604C-BEVALZ Quick setup guide

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
1
DESCRIPTION
Demonstration circuit SCP-LT8604C-BEVALZ is a high ef-
ficiency 42V, 1 20mA synchronous step-down regulator.
The wide input range also allows inversion if using the
SCP-LT8604C-IEVALZ-version.
Like all boards in the Signal Chain Power series, this board
is designed to be easily plugged into other SCP boards to
form a complete signal chain power system, enabling fast
evaluation of low power signal chains. To evaluate this
board, some universal SCP hardware is required, namely:
SCP-INPUT-EVALZ SCP-1X2BKOUT-EVALZ
SCP-OUTPUT-EVALZ SCP-1X5BKOUT-EVALZ
SCP-F ILT E R -EVALZ SCP-5X1-EVALZ
SCP-THRUBRD-EVALZ
To properly evaluate SCP series demo boards, you will
need the SCP Configurator companion software. SCP
Configurator can help you choose the right board and to-
pology for your design.
Note that this Demo Manual does not cover details im-
portant to the operation and configuration regarding the
LT8604C. Please refer to the LT8604C datasheet for a com-
plete description of the part.
Design files for this circuit board are available
All registered trademarks and trademarks are property of their respective owners.
Table 1. Performance Summary
SYMBOL
PARAMETER
NOTES
MIN
TYP
MAX
UNITS
V
IN(MAX)
Max Input Voltage
42
V
V
OUT(MAX)
Max Output Voltage
34
V
I
OUT(MAX)
Max Output Current
120
mA
BOARD IMAGE
Figure 1. SCP-LT8604C-BEVALZ Evaluation Board
DEMO MANUAL
SCP-LT8604C-B E VA L Z
Signal Chain Power Series
LT8604C High Efficiency
Synchronous Buck Converter

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
2
QUICK START PROCEDURE
Demonstration circuit SCP-LT8604C-BEVALZ is easy to
set up to evaluate the performance of any SCP hard-
ware configuration. Refer to Figure 2 and follow these
steps :
1. The SCP-LT8604C-BEVALZ ships with a default output
voltage of 5V. To change the output voltage, see “Con-
figuration Settings” below, and modify the board ac-
cordingly. Be sure to check for open connections or sol-
der shorts after making any modifications.
2. Connect the SCP-INPUT-EVALZ and SCP-OUTPUT-
EVALZ boards to the SCP-LT8604C-BEVALZ (refer to
Figure 2) and connect the input board to a voltage
source, V
SOURCE
. Connect the output board to a volt-
meter or dynamic load. Slowly raise the input voltage
until the SCP-LT8604C-BEVALZ powers into regulation
and sweep V
SOURCE
through the desired range of oper-
ation.
NOTE: Make sure that the input voltage is always within
spec. If using a dynamic load to measure output volt-
age, make sure the load is initially set to zero.
3. Check for proper output voltages. The output should be
regulated at the programmed value (±5%).
4. Once the proper output voltage is established, power
off V
SOURCE
and similarly test other boards in the SCP
system until all elements have been individually verified
prior to assembling into the final circuit configuration.
NOTE: When measuring the input or output voltage rip-
ple, use the optional SMA connector locations available
on the input, output, 1 × 5, 1 × 2, and 5 × 1 breakout
boards. Avoid using the test point connections with
long scope leads.
Figure 2. Proper Measurement Equipment Setup (Use SMA connectors for Measuring Input or Output Ripple)

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
3
CONFIGURATION SETTINGS
Demonstration circuit SCP-LT8604C-BEVALZ is a high ef-
ficiency 42V, 1 20mA synchronous step-down regulator.
The wide input range also allows inversion if using the
SCP-LT8604C-IEVALZ version.
The output of the SCP-LT8604C-BEVALZ is resistor-pro-
grammable from 0.8V to 34V.
OUTPUT VOLTAGE
OUT
R4
V 0.778V 1 R5

= +


For output voltage greater than 25V, disconnect BIAS pin
from output by removing R9.
Table 2. Resistor selection guide for common output voltages.
V
OUT
(V)
R4 (Ω)
R5 (Ω)
0.8V
3.24K
115K
0.9V
3.83K
137K
1.0V
102K
357K
1.1V
42.2K
102K
1.2V
102K
187K
1.25V
162K
267K
1.5V
205K
221K
1.8V
1.00M
768K
2.0 V
1.15M
732K
2.5V
1.47M
665K
3.0V
1.02M
357K
3.3V
590K
182K
3.5V
357K
102K
4.0V
422K
102K
4.5V
511K
107K
5.0V
1.02M
187K
5.5V
698K
115K
6.0V
1.13M
169K
6.5V
787K
107K
7.0V
1.50M
187K
7.5V
1.27M
147K
8.0V
1.30M
140K
12.0V
1.47M
102K
16.0V
1.50M
76.8K
20.0V
1.50M
60.4K
24.0V
1.50M
49.9K
25.0V
1.62M
52.3K
28.0V
1.62M
46.4K
30.0V
1.62M
43.2K
34.0V
1.33M
30.9K
ENABLE PIN/UV PIN CONFIGURATION
The EN/UV pin is tied to the optional SCP Run/Sequence
header P1. To create a harness for this function, use Molex
part # 0510650300 with crimp pin # 50212-8000.
To use an active run signal, use the default 1.00M for ei-
ther pull-up or pull-down resistors R1, R6 and R7, short
R11 with 0 Ω , and use the drive signal from connector P1.
Also, short R12 with 0 Ω for V
OUT
monitoring.
If precision UVLO operation is desired, program enable di-
vider R1, R6 and R7 such that:
R6 is 10k to 100k, nominal
()
IN
V 1.04V
R1 R6 R7 1.04V
−

=

+

The LT8604C has an accurate 1.04V threshold which
places the part into under voltage lockout. The hysteresis
threshold on the rising edge is typically 40mV and scales
by the factor:
HYST
R1 R6
V 40mV R6
+
=
Additional hysteresis may be added with the use of the
HYST pin (LT8604C only) by adding a pull-down resistor
R7 in the HYST pin, forming voltage divider with R1 and
R6.
HYST(TH)
R1 R6
RISING V 1.04V R6
+
=
HYST(TH)
R1 R6 R7
FALLING V 1.00V R6 R7
++
=+
Be aware that the HYST pin cannot be allowed to exceed
its absolute maximum rating of 12V.
IN(MAX)
R7
V 12V
R1 R6 R7

•<

++


DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
4
VOLTAGE INPUT-TO-OUTPUT CONTROL (VIOC)
IMPLEMENTATION
To implement the VIOC, set R19 = R13 = 0 Ω and refer to
the configuration sheet for the VIOC for the V
LDOOUT
volt-
age configuration values (set on the LDO board), and use
the following configuration for this board:
Table 3. VIOC Reference Designation
VIOC SETTING REFS
R
BOT
R
TOP
R
MAX
VOUT Refs
R5
R4
R8
BOT TOP
LDOIN LDOOUT VIOC
BOT
RR
V V V 0.778V R

+
−==


( )
BOT TOP MAX SINK MAX
MAX LDOIN BOT
RRR
V 0.778V I R
R

++
= +


I
SINK
is the current through R
MAX
, typically 15µA, so R
BOT
should be sized such that the divider current runs a mini-
mum of 100µA to minimize the I
SINK
error term.
FREQUENCY PIN CONFIGURATION
The LT8604C allows the user to program an operating fre-
quency by a single resistor. The default operating fre-
quency is 2.0MHz. Note that changing the switching fre-
quency may affect other parameters and likely necessitate
a change in inductor and compensation component val-
ues. Contact the SCP team for applications support if
shifting the switching frequency greater than ±10%.
Table 4. Resistor Selection Guide for Switching Frequency Setting
f
SW
R2 (Ω) f
SW
R2 (Ω)
200kHz
221k
1.30MHz
30.1k
300kHz
143k
1.40MHz
27.4k
400kHz
110k
1.50MHz
25.5k
500kHz
86.6k
1.60MHz
23.7k
600kHz
71.5k
1.70MHz
22.1k
700kHz
60.4k
1.80MHz
20.5k
800kHz
52.3k
1.90MHz
19.1k
900kHz
46.4k
2.00MHz
18.2k
1.00MHz
40.2k
2.10MHz
16.9k
1.10MHz
36.5k
2.20MHz
16.2k
1.20MHz
33.2k

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
5
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
1
PCB
PCB
ANALOG DEVICES 08_065090a
2
1
C1
CAP ALUM ELECT 22uF 63V 20% 6.3X7.7mm
UNITED CHEMI CON EMVE630ADA220MF80G
3
1
C2
CAP CER 1uF 50V 10% X7R 1206
YAGEO CC1206KKX7R9BB105
4
1
C3
CAP CER 0.1uF 50V 10% X7R 0603
SAMSUNG CL10B104KB8NNNC
5
1
C5
CAP CER 10pF 50V 5% C0G 0603
SAMSUNG CL10C100JB8NNNC
6
1
C6
CAP CER 10uF 50V 20% X5R 1206
SAMSUNG CL31A106MBHNNNE
7
1
C8
CAP CER 0.01uF 50V 10% X7R 0603
YAGEO CC0603KRX7R9BB103
8
1
C9
CAP CER 4.7uF 50V 10% X7R 1206
SAMSUNG CL31B475KBHNNNE
9
1
INPUT
CONN-PCB MALE HEADER 3POS 2.54MM PITCH R/A GOLD
SULLINS PBC03SBAN
10
1
J1
CONN-PCB STRAIGHT SMA PCB DIE CAST (Note 1)
TE CONNECTIVITY LTD 5-1814832-2
11
1
L1
IND SHIELDED POWER, 33uH 0.66OHM DCR 0.42A
WURTH ELEKTRONIK 744031330
12
1
OUTPUT
CONN FEMALE 3POS 2.54MM PITCH R/A GOLD
SULLINS PPPC031LGBN-RC
13
1
P1
CONN-PCB 3POS HEADER WIRE TO BRD WAFER ASSY
STRAIGHT 2MM PITCH (Note 1)
MOLEX 53253-0370
14
1
R1
RES SMD 1MEG Ohm 5% 1/8W 0805
YAGEO RC0805JR-071ML
15
10
R6, R7, R10, R11,
R12, R13, R19, R20,
R21, R22
DO NOT INSTALL (Note 1)
TBD0805
16
3
R14, R15, R16
RES SMD 0 Ohm 3/4W 0612
VISHAY RCL06120000Z0EA
17
2
R17, R18
RES SMD 0 Ohm 3/4W 0612 (Note 1)
VISHAY RCL06120000Z0EA
18
1
R2
RES SMD 18.2K Ohm 1% 1/8W 0805
PANASONIC ERJ-6ENF1822V
19
1
R3
RES SMD 49.9K Ohm 1% 1/10W 0603
PANASONIC ERJ-3EKF4992V
20
1
R4
RES SMD 1MEG Ohm 1% 1/8W 0805
PANASONIC ERJ-6ENF1004V
21
1
R5
RES SMD 187K Ohm 1% 1/8W 0805
PANASONIC ERJ-6ENF1873V
22
2
R8, R9
RES SMD 0 Ohm JUMPER 1/8W 0805 (Note 2)
VISHAY CRCW08050000Z0EA
23
1
U1
IC-ADI HIGH EFFICIENCY 42V/120MA SYNCHRONOUS BUCK
ANALOG DEVICES LT8604CEV#TRPBF
24
1
VIOC
CONN FEMALE 2POS 2.54MM PITCH R/A GOLD
SULLINS PPPC021LGBN-RC
Note 1. These items are not stuffed (DNI).
Note 2. Keep R9 stuffed for output voltages of 3.3V to 25V.

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
6
SCHEMATIC DIAGRAM
LT8604C BUCK
2 2
<DESI GN_VI EW>
: LT8604
Pr oduc t ( s) : LT8604
HW TYPE : Cus t omer Eval uat i on
1: 1
A
02_065090
A SERQUI NA
DNI LT8 604 CEV#TRPBF 49. 9K
DNI
DNI
53 253 - 03 70
5- 1 814 83 2- 2
DNI
50 V
DNI
0
50 V 50V
4. 7 UF10 UF1MEG
0
DNI
33 UH
DNI
10 PF
DNI
22 UF
DNI 1MEG
50 V 50V 1UF
DNI
DNI
PBC03 SBAN PPPC031LGBN- RC
63 V
18 7K
DNI
PPPC021LGBN- RC
0
0
DNI
0
DNI
DNI
18 . 2K
0. 1 UF
0. 0 1UF
U1
R6
R22
J1
R4
R19
C6
TP1
R10 R5
L1
R2
C5
R20
R21
R12
R11
R7
C2
R1
P1
INPUT
C1
OUTPUT VIOC
R13
C9
R8
R14
R16
R17
R15
R3
R18
R9
C3
C8
SYNC
VI OC
VNEG
RUN
SYNC
SYNC
RUN
VO+
VNEG
V+
VI OC
GND
VNEG VO- GND
GND VO- VO+
VNEG
GND
GND
DNC
SW
BIAS
RT SYNC/MODE TR/SS
FB
PG
HYST EN/UV VIN
D
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THEEQUIPMENTSHOWNHEREON MAYBE PROTECTEDBY PATENTS
A
C
ITIS NOT TO BE REPRODUCEDORCOPIED, INWHOLE OR
DRAWING NO.
2
SCALE
D
D
D
SIZE
D
REV
SHEET
1
1
A
2
3
4
3
5
8
D
7
67
8
A
B
CC
D
5
4
APPROVED
B
6
DESCRIPTION
REVISIONS
OF
OL G
E
OWNEDOR CONTROLLEDBYOWNEDANALOG DEVICES.
E
AN
V
OFANALOGDEVICES.
SCHEMATIC
S
PTD ENG INEER DESIGN V IEW
REV DATE

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
7

DEMO MANUAL SCP-LT8604C-B E VA L Z
Rev. 0
8
11/21
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