Linear DC1395A, LT3505EDD Quick Start Manual

QUICK START GUIDE FO

R

A

LT3505EDD:

PMIC High Voltage

LT3505EDD

DC1395

Adaptor Board with 5 Volt Adaptor Inputs

DESCRIPTION

Demonstration Circuit 1395A is a 1.2A, Step-Down

Switching Regulator in a 3mm × 3mm DFN. The

LT3505EDD is available in an 8-pin (3mm × 3mm)
DFN surface mount package.

L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered

trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy
Drive, FilterCAD, Hot Swap, LinearView, μModule, Micropower SwitcherCAD, Multimode
Dimming, No Latency ΔΣ, No Latency Delta-Sigma, No R
PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT,
UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names
may be trademarks of the companies that manufacture the products.

, Operational Filter, PanelProtect,

SENSE

PERFORMANCE SUMMARY

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

HVIN
5V ADAPTOR 5V Adaptor Input Voltage Range
HVBUCK
I

HVBUCK

High Voltage Input Voltage Range Input disabled from 36-40V 8 40 V

Output Voltage Range Range is mode and load dependant
Output Current 2 A

Specifications are at TA = 25°C

4.5 5.5 V

3.5 5.5 V

QUICK START PROCEDURE

Using short twisted pair leads for any power con­nections, with all loads and power supplies off, refer
to Figures 1 & 2 for the proper measurement and
equipment setup.

A companion PMIC demo board is required for this
check out procedure. The DC1303A
(LTC4098EPDC) board is recommended, and will be
used for the following procedure. Please refer to
the DC1303A Quick Start Guide for further informa­tion.

Follow the procedure below:

1. Set PS1 to 8V, PS2 to 0V, and PS3 to 3.6V. Set
Load1 to 0A. Ensure that jumpers are config­ured as per Figure 1, except the “D2” jumper
(JP3) on the DC1303A should be set to “1”.

2. Observe that 4.50V < VOUT (VM3) < 4.70V. The
LT3480 HV Buck regulator is running with its
control loop closed locally. The nominal
HVBUCK voltage is 4.75V, and the

LTC4098EPDC on the DC1303A board has con­nected HVBUCK to VOUT.

3. Set Load1 to 1A. Observe that 4.35V < VOUT
(VM3) 4.55V. Set Load1 to 0A. The 1A load on
VOUT loads HVBUCK, so the LT3505EDD is
supplying 1A.

4. Set PS1 to 36V. Observe that 4.50V < VOUT
(VM3) < 4.70V. The LT3505 is designed to op­erate from HVIN = 8V to 36V.

5. Set Load1 to 1A. Observe that 4.20V < VOUT
(VM3) < 4.55V. Set Load1 to 0A. The LT3505
is now supplying 1A, while operating from 38V.

6. Set “COMP” jumper (JP2) to “REMOTE”. Ob­serve that 3.80V < VOUT (VM3) < 4.10V. The
LTC4098EPDC is now controlling the LT3505
output voltage to approximately V(BAT) + 0.3V.

7. Set Load1 to 1A. Observe that 3.70V < VOUT
(VM3) < 3.90V. Set Load1 to 0A. LT3505 is
supplying 1A, while under LTC4098 control.

8. Set PS1 to 8V. Observe that 3.80V < VOUT
(VM3) < 4.10V.

1

LT3505EDD

9. Set Load1 to 1A. Observe that 3.70V < (VM3) <

3.90V. Set Load1 to 0A.

10. Set PS2 to 4.5V, and “WALL” jumper (JP3) to
“5V ADAPTOR”. Observe that 4.40 < VOUT
(VM3) < 4.50V. The LT3505 is not supplying
power to VOUT. This verifies that the LTC4098
recognizes the 5V Adaptor input, and connects it
to VOUT.

11. Set Load1 to 1A. Observe that 4.10V < VOUT
(VM3) < 4.40V. Set Load1 to 0A.

12.

Set PS2 to 5.5V. Observe that 5.40V < VOUT
(VM3) < 5.50V.

13.

Set Load1 to 1A. Observe that 5.10V < VOUT
(VM3) < 5.50V.

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