!" User’s Guide November 2001 Power Management Products SLVU056
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use.
EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of 1.8 V to 5.5 V with an output current up to 30 mA. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Contents Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1.1 Basic Operation of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 2 EVM Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Schematic of the EVM . . . . . . . . . . . . . .
Contents vi
Chapter 1 Introduction The evaluation module (EVM) for the new Texas Instruments (TI) charge pump devices REG710–25 to REG710–5 helps designers to evaluate these devices. With these EVMs it is possible to evaluate all different modes of the devices, as well as their performance. Only a dc voltage source is needed to operate the EVM. The layout of charge pumps is critical, similar to the layout of inductive dc/dc converters.
Basic Operation of the Device 1.1 Basic Operation of the Device Except for the REG710–5, the REG710 series of charge pumps work in a buck/boost fashion. They will produce a regulated output over the entire input range. The charge pump consists of switches, oscillator, bandgap, comparator, and mode control circuits. The comparator senses a divided down version of output voltage and compares that to the bandgap voltage. If the sensed output voltage is less than the bandgap voltage, the part begins pumping.
Chapter 2 EVM Description This Chapter illustrates EVM schematics, layout, and EVM setup Topic Page 2.1 Schematic of EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.2 Layout of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 2.3 Setup of the EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic of the EVM 2.1 Schematic of the EVM Figure 2–1. Schematic of the EVM C2 5 0.22 µF 4 6 VI VO C1 2.2 µF U1 REG710 3 1 C3 2.2 µF Venable GND 2 For all necessary signals there are single-pin connectors on the board. To operate the board, connect a power source with the appropriate voltage level between VIN and GND. A pullup resistor at EN may be added to ensure that the device starts without a signal applied to the EN-pin. Connect EN to GND to disable the device.
Layout of the EVM 2.2 Layout of the EVM Figure 2–2 shows the placement of the components of the EVM. The components are only placed on the top layer of the board, and the board is routed with a single layer of metal. The size of the EVM is 2 inches x 2 inches. The total space required for the IC and the capacitors on the EVM is only about 0.08 in2 (approximately 52 mm2). The capacitors are optimized for space and performance and have been laid out for 0805 sized pads. Figure 2–2.
Setup of the EVM 2.3 Setup of the EVM For proper operation of the EVM, follow these steps: 1) Connect a signal source (or a battery pack) with the appropriate voltage between the VIN and GND: REG710–25, 27, 3, 33: REG710–5: VIN >= 1.8 V VIN>= 2.7 V 2) Connect a load to the output between VOUT and GND. REG710–25, 27, 3, 33: REG710–5: Iload <= 10 mA with VIN >= 1.8 V Iload <= 10 mA with VIN >= 2.7 V REG710–25, 27: REG710–3, 33: REG710–5: Iload <= 30 mA with VIN >= 2.0 V Iload <= 30 mA with VIN >= 2.
