SP6122EB [SIPEX]

Evaluation Board Manual; 评估板手册


型号：	SP6122EB
厂家：	SIPEX CORPORATION
描述：	Evaluation Board Manual 评估板手册
文件：	总6页 (文件大小：319K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SP6122

Evaluation Board Manual

§ Easy Evaluation for the

SP6122 Low Voltage PFET

Buck Converter

§ Ideal for 1A to 5A, Small

Footprint, DC-DC Power

Converters

§ Very Accurate 1.5%

Reference over Line, Load,

Temperature

§ Small Micro 8 Package

DESCRIPTION

The SP6122 Evaluation Board is designed to help the user evaluate the performance

of the SP6122 for use as a low voltage input, low voltage output PFET Buck DC-DC

Controller. The SP6122 operates from a 5V or 3.3V input supply, and delivers output

voltages as low as 1.5V with an accuracy of 1.5% over line, load and temperature.

Unlike other “Micro-8” parts, the SP6122 has an array of value added features for you to

evaluate including: optional hiccup mode, over-current protection and fault flag output.

The evaluation board is a completely assembled and tested surface mount power

supply board which provides easy access to the SP6122 Input and Outputs so that the

user can quickly measure electrical characteristics and waveforms.

The next two sections describe the SP6122 Board Layout and Using the SP6122

Evaluation Boards. A section on SP6122 Power Supply Data is also included with

graphs on Efficiency, Line and Load Regulation. Then, drawings of the PC Layout and

a schematic are included as a design-in tool for the user of the SP6122. Finally, a

SP6122 Evaluation Board List of Materials table is provided with some manufacturers

part numbers to use as a reference.

BOARD LAYOUT

The SP6122 Evaluation Board has been designed for quick and easy connection to

the Input and Output of the SP6122 Power Supply under test. Position the board with

the silkscreen lettering upright, (also see the drawing on the front page of this manual)

and you will see U1 the SP6122 8-pin mSOIC, in the center left of the board. To the left

of U1 are the output capacitor Cout and the Vout pin. To the right of U1 are Q1 and the

Vin post and the input capacitor Cin. Below Cin and Cout are the two GND posts.

Rev. 5/23/01

SP6122 Evaluation Board Manual

USING THE EVALUATION BOARD

1) Powering Up the SP6122 Circuit

The SP6122 Evaluation Board can be powered from inputs from a +3V to +7V power

supply. Connect with short leads directly to the “Vin” and “Gnd” posts. Monitor the

Output Voltage and connect the Load between the “Vout” post and the 2^nd“GND” post.

2) Using the J1 Jumper: Enabling the SP6122 Output and using the Hiccup Mode

As you can see in table 1, the SP6122 output will be Enabled if the J1 Jumper is left

open. If J1 is in the pin 2 to 3 position, the ENABLE pin is brought to GND, which puts

the SP6122 in the Sleep Mode. If the Jumper at J1 is in the pin 1 to 2 position, FFLAG

U1 pin 2 is connected to ENABLE U1 pin 4, and Hiccup Mode is activated. Hiccup

Mode occurs if the output current exceeds the Over-Current-Protection threshold, and

the part will “Soft-start”, which happens every 1.2msec for a CEN capacitor value of

4.7nF. This is determined by the following relationship:

I = CEN*dV/dt

which yields dt = CEN*dV/I = 1.2msec

where the value of the CEN capacitor is 4.7nF, dV is the 1V internal threshold for

charging, and I is the Enable pin source current of 4uA.

SP6122

J1 Position

open

Mode

Enabled

Hiccup

Sleep

Condition

Normal

Softstarts if Over-Current

Iq = 20uA (max)

1 to 2

2 to 3

Table 1. SP6122 Enable/Hiccup Jumper

3) Using External Divider Resistors: Programming the SP6122 Output Voltage

As you can see by the schematic in Figure 1, the SP6122 uses an internal feedback

divider to initially trim the output voltage using Rin1 and Rin2, where Rin2 is

approximately 62.5K. To accommodate the user who wants to externally program the

SP6122 output voltage, the SP6122 Evaluation Board has 2 external divider resistors,

R1 and R2, which can be used to program the output voltage above, but not below the

voltage set by the internal resistor divider. The relationships for the external divider

resistors are derived below:

i1 = Va/Rin2 = 1.25/62.5K = 20uA

Since Rin2 has +/-50% tolerance, ib change is +20uA/-7uA. If the SP6122 is trimmed to

1.5V output, Vb will be fixed at 1.5V in a closed loop. As a result, i2 is not affected by

the variation of the internal resistors, and the +20uA/-7uA current variation will be

passed on to i3.

Vout = Vb+i3*R1,

Therefore, DVout = Di3*R1=+20uA/-7uA*R1.

That is, the additional variation on the output voltage is caused by the internal voltage

divider. For example, with R1 selected to be 500ohm, the variation on the output

voltage will be +10mV/-3.5mV.

Rev. 5/23/01

SP6122 Evaluation Board Manual

SP612 Evaluation Board Divider Resistors: The values of R1 and R2 are selected

to program 1.9V output, with 1.5V trim voltage Vb, and R1 = 500ohm:

i3 = (Vout-Vb)/R1=(1.9-1.5)/500 = 800uA.

The external voltage divider will add only 800uA to the load. Divider Resistor R2 is:

R2 = Vb/(i3-i1)=1.5/(800uA-20uA) = 1.9K

The user of the SP6122 Evaluation Board can use the above equations for i3 and R2 to

modify R2 and change the output voltage to be any voltage from Vb (1.5V) to as high as

the input voltage. And if you want the output voltage to be the preset voltage Vb (1.5V),

just short a wire across R1.

Vout

SP6122

500

Pin3

Rin1

1.9K

Rin2

Error

Amplifier

62.5K

1.25

Figure 1. Schematic: Output Voltage Divider Resistors

POWER SUPPLY DATA

The SP6122 is engineered for size and minimum pin count, yet has a very accurate

1.5% reference over line, load and temperature. Figure 2 data shows a typical SP6122

Evaluation Board Efficiency plot, with efficiencies to 88% and output currents to 4A.

Load Regulation plot in Figure 3 shows an essentially flat response of only 3mV change

for up to 4A load. Figure 4 Line Regulation illustrates a 1.90V output that varies only

4mV or 0.2% for an input voltage change from 3.3V to 5.5V. While data on individual

power supply boards may vary, the capability of the SP6122 of achieving high accuracy

over load and line shown here is quite impressive and desirable for accurate power

supply design.

Rev. 5/23/01

SP6122 Evaluation Board Manual

SP6122 Efficiency

Iload (A)

Figure 2. SP6122 Efficiency with Vin = 3.3V, Vout = 1.93V

SP6122 Load Regulation

1.902

1.901

1.900

1.899

1.898

1.897

Iload (A)

Figure 3. SP6122 Load Regulation with Input Voltage = 3.3V

SP6122 Line Regulation

1.905

1.904

1.903

1.902

1.901

1.900

1.899

Iload (A)

Figure 4. SP6122 Line Regulation with Iload = 2A

Rev. 5/23/01

SP6122 Evaluation Board Manual

FIGURE 5: SP6122UEB COMPONENT PLACEMENT

FIGURE 6: SP6122UEB PC LAYOUT TOP SIDE

FIGURE 7: SP6122UEB PC LAYOUT BOTTOM SIDE

Rev. 5/23/01

SP6122 Evaluation Board Manual

FIGURE 8: SP6122 EVALUATION BOARD SCHEMATIC

TABLE 2: SP6122EB LIST OF MATERIALS

Ref. Qty.

Des.

Manuf.

Part Number

146-6427-00

SP6122UEB

FDS6375

STPS2L25U

Layout

Size

1"X1.5"

uSO-8

SO-8

SMB

12.9x9.4mm

1812

Component

Vendor

Phone Number

978-667-7800

310-322-3331

781-861-2650

847-639-6400

847-803-6100

978-922-6573

847-803-6100

800-DIGI-KEY

PCB

Sipex

Fairchild

STMicroelectronics

Coilcraft

SP6120 Eval PCB

5A PFET Buck Ctrl

PFET

2A Schottky 10A RMS

2.2uH Coil 5A 0.012ohm

47uF Ceramic SM 6.3V

470uF 6.3V 0.035ohm

4.7uF 10V SM X5R

DO3316P-222

C4532X5R0J476M

6TPB470M

C3216X5R1C475K

ECJ-1VB1H472K

ERJ-8ENF5000V

ERJ-8ENF1911V

ERJ-8ENF1001V

CIN

COUT

TDK

Sanyo

TDK

Panasonic

7343H

1206

0603

1206

CEN

4700pF Ceramic X7R 50V

500 OHM Thick Film Res 1%

1.91K OHM Thick Film Res 1%

1.00K OHM Thick Film Res 1%

1206

ORDERING INFORMATION

Part Number

Package Type

SP6122UEB....................................................................................... SP6122 Evaluation Board

SP6122CU..................................................................................................................8-pin mSOIC

Rev. 5/23/01

SP6122 Evaluation Board Manual

SP6122EB [SIPEX]

相关型号：

SP6122UEB

SP6122_04

SP6123

SP6123

SP6123A

SP6123A

SP6123ACN

SP6123ACN-L

SP6123ACN-L/TR

SP6123ACN.

SP6123ACN/TR

SP6123AE3